Let Us Learn Why Do Some Batteries Last Longer Than Others

It's Monday and you're late for work thanks to the sudden death of your alarm clock's batteries--the same ones you replaced not too long ago. Yet while they only lasted a few weeks, the hp batteries in your remote control have thrived for over a year. So what's the difference between them? Is it the brand? Do more expensive batteries really last longer? And why do some batteries, even when they're the same brand, last longer than others?

When you insert batteries into a device, they have to be positioned in the battery compartment with the positive and negative sides, or terminals, facing a certain way. When properly inserted, the terminals then line up with a wire spring inside the device. This wire acts as a bridge between the two terminals, allowing electrons to flow from the hp pavilion dv8000 battery into the wire, thereby charging the device and enabling it to function.

Batteries have a very long shelf life, typically lasting a year or more without losing power. Chances are, if a store is selling it, it has not yet expired and will work the same regardless of whether it's purchased a day or a year before its expiration date. So you really shouldn't have to be too concerned with the age of a hp 484784-001 battery and don't need to look for the pack with the latest expiration date stamped on it. However, even if they aren't ever activated, batteries can lose up to 20 percent of their original power per year if they're kept in a warm area (about 68 to 86 degrees F). Known as the battery's self discharge rate, this loss of power can be reduced if batteries are stored at lower temperatures. On the same token, however, extremely low temperatures can also reduce a hp compaq nc6000 battery's charge. So while it may help to store your batteries in a refrigerator, the freezer isn't such a great idea.

Assuming you already store your batteries at an appropriate temperature, what else determines whether or not they last a week, a month or a year? Well, contrary to what those commercials may state, it's really more about the type of the hp compaq 6910p battery rather than the brand. An AAA battery, for example, will last longer than a D battery. In addition, a battery's life is greatly influenced by the product in which it is used and the amount of energy required to make the device work. Although most products like CD players and clocks tend to use less energy, others such as MP3 players and cameras typically require more energy. Lithium, titanium and premium alkaline batteries are designed for these high-energy devices, whereas regular alkaline batteries work best with low-energy devices. In terms of brands, countless studies have been done with independent testing from companies like TechTV and Zbattery.com, but there has been no conclusive proof that any particular brand works better than any other. Rather, the factors that determine how long hp compaq 6710b battery is based on how they're stored and how they're used.

Heat, Loading and Battery Life

Heat is a killer of all batteries and high temperatures cannot always be avoided. This is the case with a apple computerbattery inside a laptop, a starter battery under the hood of a car and stationary batteries in a tin shelter under the hot sun. As a guideline, each 8°C (15°F) rise in temperature cuts the life of a sealed lead acid battery in half. A VRLA batteryfor stationary applications that would last 10 years at 25°C (77°F) would only live for five years if operated at 33°C (95°F). Once the battery is damaged by heat, the capacity cannot be restored. The life of a battery also depends on the activity and is shortened if the battery is stressed with frequent discharge.

According to the 2010 BCI Failure Mode Study, starter batteries have become more heat-resistant over the past 10 years. In the 2000 study, a change of 7°C (12°F) affected battery life by roughly one year; in 2010 the heat tolerance has widened to 12°C (22°F). In 1962, a starter battery lasted 34 months, and in 2000 the life expectancy had increased to 41 months. In 2010, BCI reports an average age of 55 months of use. The cooler North attains 59 months and the warmer South 47 months.

Cranking the engine poses minimal stress on a starter apple a1175 battery. This changes in a start-stop function of a micro hybrid. The micro hybrid turns the IC engine off at a red traffic light and restarts it when the traffic flows. This results in about 2,000 micro cycles per year. Data obtained from car manufacturers show a capacity drop to about 60 percent after two years of use in this configuration. To solve the problem, automakers are using specialty AGM and other variations that are more robust than the regular lead acid. Read more about Alternate Battery Systems. Figure 5 shows the drop in capacity after 700 micro cycles. The simulated start-stop test was performed in Cadex laboratories. CCA remains high.

Figure 5: Capacity drop of a flooded starter battery when micro cycling Start-stop function on a micro hybrid stresses the battery; the capacity drops to about 50 percent after two years of use. AGM is more robust for this application. Courtesy of Cadex, 2010

Test method:   The test battery was fully charged and then discharged to 70 percent to resemble the SoC of a micro hybrid in real life. The battery was then discharged at 25A for 40 seconds to simulate engine off condition at stoplight with the headlight on, before cranking the engine at 400A and recharging. The CCA readings were taken with the Spectro CA-12.

The cell voltages on a apple a1185 battery string must be similar, and this is especially important for higher-voltage VRLA batteries. With time, individual cells fall out of line, and applying an equalizing charge every six months or so should theoretically bring the cells back to similar voltage levels. While equalizing will boost the needy cells, the healthy cell get stressed if the equalizing charge is applied carelessly. What makes this service so difficult is the inability to accurately measure the condition of each cell and provide the right dose of remedy. Gel and AGM batteries have lower overcharge acceptance than the flooded version and different equalizing conditions apply. Always refer to the manufacturer’s specifications.

Water permeation, or loss of electrolyte, is a concern with sealed lead acid batteries, and overcharging contributes to this condition. While flooded systems accept water, a fill-up is not possible with VRLA. Adding water has been tried, but this does not offer a reliable fix. Experimenting with watering turns the VRLA into unreliable battery that needs high maintenance.

Flooded lead acid batteries are one of the most reliable systems. With good maintenance these batteries last up to 20 years. The disadvantages are the need for watering and providing good ventilation. When VRLA was introduced in the 1980s, manufacturers claimed similar life expectancy to flooded systems, and the telecom industry switched to these maintenance-free batteries. By mid 1990 it became apparent that the life for VRLA did not replicate that of a flooded type; the useful service life was limited to only 5–10 years. It was furthermore noticed that exposing the batteries to temperatures above 40°C (104°F) could cause a thermal runaway condition due to dry-out.

A new lead acid battery should have an open circuit voltage of 2.125V/cell. At this time, the apple powerbook g4 12 battery is fully charged. During buyer acceptance, the lead acid may drop to between 2.120V and 2.125V/cell. Shipping, dealer storage and installation will decrease the voltage further but the battery should never go much below 2.10V/cell. This would cause sulfation. Battery type, applying a charge or discharge within 24 hours before taking a voltage measurement, as well as temperature will affect the voltage reading. A lower temperature raises the OCV; warm ambient lowers it. 

Battery Definitions

Batteries come in all shapes and sizes and there could be as many types as there are species of dog. Rather than giving batteries unique names as we do with pets, we distinguish batteries by chemistry, voltage, size, specific energy (capacity), specific power, (delivery of power) and more. A battery can operate as a single cell to power a cellular phone, or be connected in series to deliver several hundred volts to serve a UPS (uninterruptible power supply system) and the electric powertrain of a vehicle. Some batteries have high capacity but cannot deliver much power, while a starter battery has a relatively low capacity but can crank the engine with 300A.

The largest battery systems are used for grid storage to store and delivery energy derived from renewable power sources such as wind turbines and solar systems. A 30-megawatt (MW) wind farm uses a storage battery of about 15MW. This is the equivalent of 20,000 starter batteries and costs about $10 million. One mega-watt feeds 50 houses or a super Walmart store. Let’s now examine each of the hp pavilion dv6 battery characteristics further.

Chemistry
The most common chemistries are lead, nickel and lithium. Each system requires its own charging algorithm. Unless provisions are made to change the charge setting, different battery chemistries cannot be interchanged in the same charger. Also observe the chemistry when shipping and disposing of batteries; each type has a different regulatory requirement.

Voltage
Voltage describes the nominal open circuit voltage (OCV), which varies with chemistry and number of cells connected in series. Always observe the correct voltage when connecting to a load or a charger. Do not proceed if the voltage does not agree.

Capacity
Capacity represents the specific energy in ampere-hours (Ah). Manufacturers often overrate a hp pavilion dv7 battery by giving a higher Ah rating than it can provide. You can use a battery with different Ah (but correct voltage), provided the rating is high enough. Chargers have some tolerance to batteries with different Ah ratings. A larger battery will take longer to charge than a small one.

Cold cranking amps (CCA)
CCA specifies the ability to draw high load current at –18°C (0°F) on starter batteries. Different norms specify dissimilar load durations and end voltages.

Specific energy and energy density
Specific energy orgravimetric energy density defines the battery capacity in weight (Wh/kg); energy density or volumetric energy density is given in size (Wh/l). A battery can have a high specific energy but poor specific power (load capability), as is the case in an alkaline battery. Alternatively, a battery may have a low specific energy but can deliver high specific power, as is possible with the supercapacitor. Specific energy is synonymous with battery capacity and runtime.

Specific power
Specific power or gravimetric power density indicates the loading capability, or the amount of current the hp pavilion dv8 battery can provide. Batteries for power tools exhibit high specific power but have reduced specific energy (capacity). Specific power is synonymous with low internal resistance and the delivery of power.

C-rates
C-rates specify charge and discharge currents. At 1C, the battery charges and discharges at a current that is par with the marked Ah rating; at 0.5C the current is half, and at 0.1C it is one tenth. On charge, 1C charges a good battery in about one hour; 0.5C takes 2 hours and 0.1C 10 to 14 hours. Read more about What is the C-rate?

Load
Also known as electromotive force (EMF), the load draws energy from the battery. Internal hp battery resistance and depleting state-of-charge cause the voltage to drop.

Watts and Volt-amps (VA)
Power drawn from a battery is expressed in watts (W) or volt-amps (VA). Watt is the real power that is being metered; VA is the apparent power that determines the wiring sizing and the circuit breakers. On a purely resistive load, watt and VA readings are alike; a reactive load such as an inductive motor or florescent light causes a drop in the power factor (pf) from the ideal one (1) to 0.7 or lower. For example, a pf of 0.7 has a power efficiency of 70.

The Cost of Portable Power

Electrical energy from non-rechargeable  batteries is expensive in relative terms and its use is limited to low power applications such as watches, flashlights and portable entertainment devices. Cell phones, laptops and power tools run mainly on rechargeable (secondary) batteries.

In this paper we calculate the cost to produce 1000 watts of power for one hour (1kWh) from different energy storage medias. We first look at primary and secondary batteries; then compare the energy cost derived from an internal combustion motor, the fuel cell and finally the electrical grid.

The primary battery

Figure 1 reveals the cost of energy using commercial alkaline cells. The right column shows a lithium battery for still cameras and memory backup.

It can be seen that larger cells provide a lower cost per kWh than small cells. The energy cost from the AA is more than half that of the smaller AAA. The C cell provides the lowest cost per kWh. The D cell has gone up in cost because of moderate use. Advanced systems, such as lithium, provide very high energy density at a premium cost. The energy cost of the 6-volt camera battery is more than ten times that of an alkaline C cell.

Figure 1: Cost of energy obtained by primary batteries. The energy cost from primary batteries is high and increases with smaller battery sizes and systems with high energy densities. _______________ *The nominal voltage is used to calculate the Wh. Because of falling voltage during discharge, the actual energy is less than what is shown.

Primary batteries hold more energy than secondary batteries per size and weight. Operational readiness, long storage and instant readiness are other benefits. Primary batteries contain little toxic substances and are considered environmentally friendly.

The secondary battery

Secondary batteries provide far more economical energy than primaries, as Figure 2 reveals. This analysis is based on the estimated purchase price of a commercial battery pack and on the number of discharge-charge cycles it can endure before replacement is necessary. The calculated cost does not include the electricity needed for charging, nor does it account for the purchasing cost of the charging equipment.

Figure 2: Energy and cost comparison using rechargeable cells. Older chemistries are generally cheaper in costs per kWh than newer systems. Larger batteries are more cost-effective than smaller ones.

Newer chemistries provide higher energy densities than conventional batteries per size and weight but the cost per kWh is higher. This cost is, to a large extent, governed by the number of charge/discharge cycles the battery can endure.

The low costs of nickel-cadmium can only be achieved by applying a full discharge once every 1-2 month as part of a maintenance program to prevent memory. If omitted, nickel-cadmium is on par with nickel-metal-hydride and lithium-ion in terms of cycle life. Lack of maintenance would increase the cost three-fold. Environmental conditions, such as elevated temperatures and incorrect charging, reduce the expected sony battery life of all battery chemistries. The calculated cycle life is based on best cases.

By far the lowest cost per kWh is lead-acid for wheelchairs and scooters. Running a laptop off a large lead-acid battery would reduce the energy cost twenty fold. This, however, would be a hard sell. 

The combustion engine 

Figure 3 compares the energy cost to generate 1kW of energy from the primary AA alkaline cells, a nickel-cadmium pack, a combustion engine used in a midsize car, fuel cells and the electrical grid. The cost estimation takes into account the initial investment, fuel costs where applicable and eventual replacement of the systems.

Figure 3: Cost of generating 1kW of energy. This takes into account the initial investment, fuel consumption where applicable, maintenance and eventual replacement of the equipment. The lowest cost power source is the utility; the most expensive is primary batteries

The fuel cell

The fuel cell offers the most effective means of generating electricity but is expensive in terms of cost per kWh. Fuel cells, as a fujitsu battery replacement, will only become economically viable once such units are available in compact design at a reasonable price.

Fuel cells for stationary applications are still more expensive than diesel. The least viable application in terms of cost is fuel cells for vehicles. The internal combustion motor, as we know it today, is hard to beat. According to the US Department of Energy, hydrogen is four times as expensive as gasoline and the fuel cell is ten times as expensive to build as a gasoline engine. Incentives other than cost may be needed to entice motorists to switch to the environmentally friendly fuel cell.

The lowest cost per kWh is electricity from the grid. The energy can be generated in remote locations. The transportation maintenance and costs are relatively low. All costing information is based on current estimates and assumptions.

How does Internal Resistance affect Performance?

With the move from analog to digital, new demands are placed on the battery. Unlike analog portable devices that draw a steady current, the digital equipment loads the battery with short, heavy current spikes.

One of the urgent requirements of a battery for digital applications is low internal resistance. Measured in milliohms, the internal resistance is the gatekeeper that, to a large extent, determines the runtime. The lower the resistance, the less restriction the battery encounters in delivering the needed power spikes. A high mW reading can trigger an early 'low battery' indication on a seemingly good battery because the available energy cannot be delivered in the required manner and remains in the battery

Figure 1 demonstrates the voltage signature and corresponding runtime of a battery with low, medium and high internal resistance when connected to a digital load. Similar to a soft ball that easily deforms when squeezed, the voltage of a battery with high internal resistance modulates the supply voltage and leaves dips, reflecting the load pulses. These pulses push the voltage towards the end-of-discharge line, resulting in a premature cut-off. As seen in the chart, the internal resistance governs much of the runtime.

Figure 1: Discharge curve on a pulsed load with diverse internal resistance. This chart demonstrates the runtime of 3 batteries with same capacities but different internal resistance levels.

Talk-time as a function of internal resistance 

As part of ongoing research to measure the runtime of batteries with various internal resistance levels, Cadex Electronics examined several cell phone batteries that had been in service for a while. All batteries were similar in size and generated good capacity readings when checked with a battery analyzer under a steady discharge load. The nickel-cadmium pack produced a capacity of 113%, nickel-metal-hydride checked in at 107% and the lithium-ion provided 94%. The internal resistance varied widely and measured a low 155 mOhm for nickel-cadmium, a high 778 mOhm for nickel-metal-hydride and a moderate 320 mOhm for lithium-ion. These internal resistance readings are typical of aging batteries with these chemistries.

Let's now check how the test batteries perform on a cell phone. The maximum pulse current of a GSM (Global System for Mobile Communications) cell phones is 2.5 amperes. This represents a large current from a relatively small battery of about 800 milliampere (mAh) hours. A current pulse of 2.4 amperes from an 800 mAh battery, for example, correspond to a C-rate of 3C. This is three times the current rating of the battery. Such high current pulses can only be delivered if the internal battery resistance is low.

Figures 2, 3 and 4 reveal the talk time of the three lithium-ion batteries under a simulated GSM current of 1C, 2C and 3C. One can see a direct relationship between the battery's internal resistance and the talk time. nickel-cadmium performed best under the circumstances and provided a talk time of 120 minutes at a 3C discharge (orange line). nickel-metal-hydride performed only at 1C (blue line) and failed at 3C. lithium-ion allowed a moderate 50 minutes talk time at 3C.

Figure 2: Discharge and resulting talk-time of nickel-cadmium at 1C, 2C and 3C under the GSM load schedule. The battery tested has a capacity of 113%, the internal resistance is a low 155 mOhm.

Figure 3: Discharge and resulting talk-time of nickel-metal-hydride at 1C, 2C and 3C under the GSM load schedule. The battery tested has a capacity of 107%, the internal resistance is a high 778 mOhm.
Figure 4: Discharge and resulting talk-time of a lithium-ion battery at 1C, 2C and 3C under the GSM load schedule. The battery tested has a capacity of 94%, the internal resistance is 320 mOhm. 

Internal resistance as a function of state-of-charge

The internal resistance varies with the state-of-charge of the toshiba satellite a350 battery. The largest changes are noticeable on nickel-based batteries. In Figure 5, we observe the internal resistance of nickel-metal-hydride when empty, during charge, at full charge and after a 4-hour rest period.

The resistance levels are highest at low state-of-charge and immediately after charging. Contrary to popular belief, the best battery performance is not achieved immediately after a full charge but following a rest period of a few hours. During discharge, the internal battery resistance decreases, reaches the lowest point at half charge and starts creeping up again (dotted line).

Figure 5: Internal resistance in nickel-metal-hydride. Note the higher readings immediately after a full discharge and full charge. Resting a battery before use produces the best results. References: Shukla et al. 1998. Rodrigues et al. 1999.

The internal resistance of lithium-ion is fairly flat from empty to full charge. The battery decreases asymptotically from 270 mW at 0% to 250 mW at 70% state-of-charge. The largest changes occur between 0% and 30% SoC.

The resistance of lead acid goes up with discharge. This change is caused by the decrease of the specific gravity, a depletion of the electrolyte as it becomes more watery. The resistance increase is almost linear with the decrease of the specific gravity. A rest of a few hours will partially restore the battery as the sulphate ions can replenish themselves. The resistance change between full charge and discharge is about 40%. Cold temperature increases the internal resistance on all batteries and adds about 50% between +30°C and -18°C to lead acid batteries. Figure 6 reveals the increase of the internal resistance of a gelled lead acid toshiba satellite a200 battery used for wheelchairs. 

Figure 6: Typical internal resistance readings of a lead acid wheelchair battery. The battery was discharged from full charge to 10.50V. The readings were taken at open circuit voltage (OCV). Cadex battery laboratories.

Batteries for Transportation, Aerospace

Battery-powered Vehicles

Batteries for propulsion systems have been in use for over 100 years, and today electric powertrains drive robots, bicycles, wheelchairs, golf cars, forklifts, EVs and underwater vessels. This power source has one thing in common; it is pollution-free and can be used indoors and underwater. For reasons of battery size, propulsion systems for heavy outdoor equipment such as earthmoving machines, non-electrified trains, aircraft and large ships must continue to rely on fossil fuel.

Most electric bicycles in developing countries run on lead acid batteries. While inexpensive, lead acid for deep-cycle use is ill suited and the batteries last for only 9 to 12 months on a daily commute. Nickel- or lithium-based batteries with twice and three-times the specific energy offer better cycle performance and shorter charge times but are expensive. While lead acid comes in at less than $100 a pack, a nickel-based battery costs $400–500, and a high-end Li-ion goes for $800–1,200. At a capacity of 280–480Wh, the battery has a range of 20–40km. With flat terrain and good wind conditions, the battery power with 70 percent pedal assist is only 1kW per kilometer (1.6kW per mile). Uphill propulsion consumes up to 10Wh/km (16kW per mile).

The battery cost dictates the developing world to choose lead acid. If the commuter had a bit more money he would likely buy a motorcycle. In the wealthy West, bicycle owners use their bicycles more as a form of recreation than a necessity. They have the means to go for a better battery, and advanced e-bikes with NiMH and Li-ion batteries sell for several thousand dollars. Europe is leading in the up-scale electrical bicycle and the trend is spreading.

Wheelchairs, scooters and golf cars use mostly lead acid batteries. Even though heavy, lead acid works reasonably well and alternative chemistries would be too expensive. While wheelchair batteries tend to have a short service life span of about two years, a similar battery in a golf car can last for 4 to 5 years. This, I believe, is due to charging practices. The lead acid battery needs a fully saturated charge of 14–16 hours to prevent sulfation, and the time is not always available for the daily wheelchair user who may only charge the battery for eight hours while asleep. Golf car batteries, on the other hand, typically receive the needed 14–16 hours in a full overnight charge.

Ever since the starter motor was invented in 1912, lead acid batteries began cranking engines and providing power for lighting and ignition. Low cost and high current loading make lead acid an almost perfect candidate for starter applications. A typical starter battery has about 720 watts, and one of its unique qualities is good cranking ability even when the capacity fades to 25 percent or less.
Hybrids, plug-ins and electric vehicles use larger batteries, and Figure 1 compares the battery sizes. While the hybrid can get by with a battery twice the size of a starter battery, plug-in vehicles carry batteries in the 5–15kWh range, and the pure EV includes a monster battery ranging from 20 to 50kWh. Read more about the Electric Vehicle.




Figure 1: Typical battery wattages of vehicle batteries. While starter and hybrid batteries are tolerant to capacity fade, a weak EV battery travels shorter distances.
Courtesy of Cadex

The automotive industry is very conservative, and the choice of toshiba pa3819u-1brs battery for most modern electric powertrains is lithium-ion with a nickel-manganese-cobalt mix (NMC). These cells provide stable service for many years and have low self-discharge, even when aging. NMC is also a desirable battery for power tools. Another strong candidate is Li-phosphate, a battery that delivers the best cycle life and is safe but has higher self-discharge than NMC. This complicates battery management, especially if the cells age differently.

University students converting an old Volkswagen Beetle to an electric powertrain to drive around the globe would shop for a lower-priced alternative and likely find a source in China. China offers Li-ion mono-blocks in 40–800Ah sizes at attractive prices. These batteries work well for less demanding applications and are great for experimental uses. There is, however, concern about safety and reliability when placed into the hands of common consumers.

The need of a battery management system becomes evident. It prevents any cell from exceeding 4.25V/cell on charge and dropping below 3.00V on discharge. As the cells age, cell capacities diverge and this affects charge and discharge times. On charge, a weak cell reaches full charge first, and without limit the voltage would rise further. On discharge, the weak cell discharges first and needs protection from voltage depletion. Weak cells are at a disadvantage; they get stressed the most and lose capacity quicker than the strong cells in a pack.

Forklifts use mostly lead acid batteries. Here, the weight is of little concern, however, long charging times is a disadvantage for warehouses operating 24 hours a day. This limits the fleet operation to only one shift. Fuel cell makers are gaining inroads by offering charging while the vehicle is in use. The addition of a fuel cell serving as onboard charger reduces battery size, but eliminating the battery entirely is not possible. The fuel cell has poor response characteristics on power demand and lacks the needed power bandwidth; the toshiba pa3450u-1brs battery fills in for these shortcomings. Read more about the fuel cell.

The heavier the wheeled application, the more difficult it becomes to use batteries as the main powertrain. This does not prevent engineers from looking into alternate power sources to replace polluting diesel engines. One application under consideration is to use batteries for the Automatic Guided Vehicle (AGV) systems at ship ports, but battery size and charging times make this unfeasible. AGVs run 24 hours a day and the vehicles cannot be removed for lengthy charging. An automated battery exchange is being considered by removing the 10-ton, 300kWh lead acid battery from the vehicle and putting it on charge. Cost and impracticality may limit such an approach.

A German firm looked at using lithium-ion batteries for AGVs to speed up charging and reduce weight. While many smaller applications have switched to this new battery system, Li-ion is not yet ready for very large applications; the cost is prohibitive and the safety of such systems remains in issue.

On large-scale applications, batteries continue to have a hard time competing with fossil fuel in terms of specific energy. While a modern Li-ion battery produces about 120Wh/kg of energy, the net calorific value (NCV) of fossil fuel is 12,000Wh/kg, or one liter, an energy that is one hundred times higher. Even at a low efficiency of 25 percent, which an IC engine delivers, batteries don’t come close to this delivery of power.

Will Li-ion advance to take this spot? Perhaps not in our lifetime. Even if modern technology enabled large energy storage devices, charging these mega-batteries in an hour could dim a city. Replacing large diesel engines with batteries does not make commercial sense for now, nor can the fuel cell fill the spot. We need to breathe diesel-polluted air a little longer.

Batteries for Aviation

The duty of batteries on board aircraft is to run navigation and emergency systems when the Auxiliary Power Unit (APU) is off or if an emergency occurs. In the event of an engine failure, the batteries must supply energy from 30 minutes to three hours. Each aircraft must also have enough toshiba pa3594u-1brs battery power to facilitate a safe landing.

Starting a large aircraft involves two stages. Most commercial jet aircraft use flooded nickel-cadmium to first engage the APU located at the tail end of a plane. The APU takes significantly longer to start and requires more energy than cranking the reciprocating engine in a vehicle. The spooling speed of the APU must be sufficiently high to attain compression for self-sustained ignition. This takes about 15 seconds and consumes 15kW of energy. Once running, an air compressor or hydraulic pump jumpstarts the large jet engines. On smaller aircraft, the battery must spool each engine for 25–40 seconds at high current. This puts far more stress on a battery than starting a car, and the batteries must be built accordingly.

Smaller aircraft may use a sealed lead-tin battery that is heavier than NiCd but has lower maintenance. The 12 and 24V aviation batteries are rated in IPP and IPR rather than CCA, as is common in the auto industry. Modern jet fighters spool the engines with lithium-ion batteries.

Durability and good performance at low temperature are the main reasons for the continued use of nickel-cadmium batteries in aviation. Most are flooded and require high maintenance that includes exercising to eliminate memory. The service consists of totally discharging the battery and placing a shortening strap across each cell for 24 hours. Each toshiba satellite a200 battery is also checked for capacity with a battery analyzer.

Although aircraft carry many batteries aboard, their sole purpose is to provide starting and backup power. No passenger would dare fly to Europe or Asia on battery power alone. One can clearly see the limitations of batteries for large engines, and we need to rely on fossil fuel a little bit longer. (Let’s not give away this precious nonrenewable resource too cheaply by allowing people to squander the oil, especially if alternative energy storage devices, i.e. the batteries, can be used for ground transportation.)

Batteries for Aerospace

Early satellites used exclusively NiCd batteries. This, by the way, exposed the “memory” phenomenon in that NiCd could remember the amount of energy that was used on a tightly regulated discharge schedule. If the discharge lasted longer than normal, the battery would suffer a mysterious voltage drop. Today, most modern satellites, including the Hubble, use nickel-hydrogen cells. One of the enduring qualities of nickel-hydrogen is long cycle life. To optimize longevity, engineers over-design the batteries to achieve a small depth of discharge of only 6 to 10 percent.

High price and large size limit nickel-hydrogen batteries for satellite applications. Each cell has the appearance of a small steam engine and costs about a thousand dollars. These batteries are specially made for the application.

Satellites designed with a life span of five years or less often use lithium-ion. A new breed of Li-ion is being developed that promises to last 18 years. This would satisfy most satellite requirements and replace the heavier nickel-based systems. The battery in development is a large 140Ah cell. Li-ion is lighter in weight, is easier to charge and has a lower self-discharge than the nickel-based toshiba satellite a350 battery systems of old. Furthermore, industrial versions of Li-ion promise to exceed the life span of nickel.

Low Voltage Cut-off

Li-ion batteries contain a protection circuit that shields the battery against abuse. This important safeguard has the disadvantage of turning the battery off if over-discharged. Storing a discharged battery for any length of time can do this. The self-discharge during storage gradually lowers the voltage of the already discharged battery and the protection circuit cuts off between 2.20 and 2.90V/cell.
Some battery chargers and analyzers, including those made by Cadex, feature a wake-up feature or “boost” to allow charging batteries that have fallen asleep. Without this feature, a charger would read these batteries as unserviceable and the packs are discarded. The boost feature applies a small charge current to activate the protection circuit to 2.20–2.90V/ cell, at which point a normal charge commences. Caution should be applied not to boost lithium-based batteries back to life that have dwelled below 1.5V/cell for a week or longer.Copper shunts may have formed inside the cells that can lead to a partial or total electrical short. If trying to recharge, such a damaged cell might become unstable, causing excessive heat or showing other anomalies.

Figure 1: Sleep mode of a lithium-ion battery Some over-discharged batteries can be “boosted” to life again. Discard pack if the voltage does not rise to a normal level within a minute while on boost.

A study of failed batteries done by Cadex reveals that three out of ten batteries die due to over-discharge. If serviced within a year or so, batteries that have fallen asleep can be revived without noticeable loss on performance. Lack of service squanders many good batteries, so much so that 90 percent of returned batteries have no fault and can be reused. The cellular industry estimates the cost of needless acer extensa 5220 battery replacement at $10 million a year. Refurbishing batteries has the added benefit of protecting the environment and keeping our planet green.

The Best Rechargeable Batteries and Chargers Of 2011

Today, the best rechargeable batteries are the new hybrid Nickel-Metal Hydride (Ni-MH) cells. These hybrid batteries have a lot going for them: they come fully charged (like alkaline batteries), and they can hold their charge over may months (unlike regular Ni-MH rechargeables). Because they can hold their charge for so long, they are suitable for low-drain devices like remote controls and flashlights. But they are also ideal for use in high-drain electronic devices like digital cameras.

So, basically, these new hybrid Ni-MH cells offer the convenience and shelf-life of alkalines, and the high-drain performance of older Ni-MH batteries. Here’s a list of the hybrid batteries available: Eneloop, E8DE 1000 and Hybrio.

If, however, being able to recharge batteries quickly is your priority, you may want to look at Rayovac’s IC3 Ni-MH batteries, which have the advantage of being able to be recharged in 15 minutes (see more information below).

We also review some of the best battery chargers at the end of this article.

Eneloop Rechargeable Batteries by Sanyo

Eneloop batteries are Ni-MH batteries made by Sanyo in Japan. Sanyo says Eneloops can be recharged up to 1000 times, and they will retain their charged capacity even after 6 or 12 months of storage. (According to Sanyo the specs are: 90% of charged capacity retained after 6 months, and 85% capacity after 12 months at 20 degree Celsius). The AA-sized (R6) batteries are rated at 2000 mAh, and the AAA-sized (R03) cells are rated at 800 mAh. A pack of four AA Eneloops costs about $12. The charge times are as follows: AA Eneloops charge in 230 minutes, and AAA Eneloops charge in 135 minutes.
You can get packs of Eneloop batteries from Amazon.

Eneloop batteries are also available with a USB Charger, or a Universal Charger with 8 Eneloop Batteries included.

E8GE 1000 Hybrid Rechargeable Batteries

E8GE Rechargeable Hybrid Batteries

The E8GE 1000 batteries are the newest hybrid batteries to be introduced, and they are also the highest rated at 2100 mAh (this stands for milli Amp hour, and indicates a battery’s energy storage capacity). Eneloops, by comparison, have a lower rated capacity — 2000 mAh (or 1980 mAh according to my informal tests).

E8DE batteries are rechargeable up to 1000 cycles, and they are “ultra-low self-discharging” batteries.
E8GE 1000 batteries are available from Amazon.

Hybrio Rechargeable Batteries by Uniross

Uniross, a French acer battery company, Ni-MH battery called the Hybrio. Like disposable alkaline batteries, they come fully charged when you buy them. Hybrios are said to keep 70% of their charge after a year.
You can recharge the Hybrios in any standard Ni-MH charger, and they can be recharged up to 500 times. A pack of four Hybrio cells costs about $12. The AA-sized Hybrios are rated at 1900 mAh. Uniross offers a three year limited warranty on these cells. They are also branded as: Ultralast, Again and Again, and Uniross.

Hybrio batteries are available from Amazon

I-C3 Rechargeable Batteries by Rayovac

In 2004, Rayovac introduced a new line of Ni-MH batteries called I-C3s, that can be recharged in 15 minutes. The I-C3 term stands for “In-Cell Charge Control”, meaning the cells have some circuitry inside them that assists with recharging, allowing for a much quicker charging time. Rayovac says the cells can be recharged “up to a thousand times”. The AA sized batteries are rated at 2000mAh. A four pack of the AA-sized batteries costs about $10. Unfortunately, Rayovac has discontinued these batteries in favor of their own line of hybrid Ni-MH batteries.

I-C3 batteries come with a special charger that features a cooling fan to keep the batteries from getting too hot during the fast charging. There are two charger models: the PS6, which can charge four AA or AAA batteries, and comes with a plug-in 110-120V AC power supply (or optionally, a 12V DC car cord). The PS5 charger model can charge two AA or AAA batteries, and plugs directly into a wall outlet. The PS5 can be used in countries with 220V using an adapter for the outlet.

Ordinary Ni-MH and Ni-CD type batteries can be charged in the I-C3 chargers, but it will act like an overnight charger with these batteries.
Rayovac IC3 Batteries are available from Amazon.

Best Battery Chargers

How about some good battery chargers to go with these batteries?
The chargers featured below are some of the smartest out there — they have built-in protection to prevent overcharging or undercharging. They can also handle most battery sizes.

LaCrosse Technology BC-900 Alpha Battery Charger and Recovery System

The LaCrosse Alpha Charger is a “smart” charger. It has sophisticated monitoring circuitry that controls the charging process, and it is also capable of “renewing” batteries by running full controlled discharge-recharge cycles.

The charger shows acer extensa 5220 battery voltage and charge status on its digital display. It has four separate charge channels so you can charge one, two three or four batteries at a time – even on individual charge programs. This allows you to test one battery while charging the others. It comes with four AA and four AAA batteries, four battery adapters (which convert AA sized battery to C and D sizes) and a carry case. It available from Amazon for about $40.
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Ansmann Deluxe “Energy 16″ Charger

Ansmann is a German company known for their range of high-end, intelligent battery chargers. Ansmann’s “Energy 16″ charger can handle both NiCad and NiMH (Nickel Metal Hydride) rechargeable batteries. When the batteries are inserted into the charger, they are analysed, and batteries needing reconditioning are automatically restored by several cycles of charging and discharging. The charger will also indicate if a acer aspire 5536 battery has been damaged and cannot be charged.

This charger has ten charging positions: six for AAA, AA, C or D sized cells, and four for 9V cells. The six top positions can handle two AAA or two AA cells or one each of the larger C or D cells.
A LED display shows the state of charging for each cell.

This charger can be used worldwide — it accepts 100-240V 50-60Hz AC.
It’s available from Amazon for around $120.

Ansmann Deluxe “Energy 8″ Charger

Ansmann’s “Energy 8″ charger has all the features of the “Energy 16″ charger, but has 8 charging points instead of 16. It has four AAA/AA/C/D and two 9V positions.
It’s available from Amazon for around $70.

Maha PowerEx “Ultimate Professional” Charger

The Maha’s Ultimate Professional Charger almost lives up to its hyperbolic name. This compact charger can charge any combination of 1 to 8 batteries. You can mix and charge AA, AAA, C and D sized cells at the same time on individual charging circuits. Each acer aspire 5920 battery size also has its own fixed contact charging points (i.e. not a spring). An LCD display shows charging and conditioning status of each rechargeable battery.

Like the Ansmann chargers, Maha’s chargers can restore batteries to their optimal performance level by repeatedly charging and discharging them. It also has intelligent charging technology and overcharge protection. It also comes with an international AC adapter, and short-circuit protection.

What is the C-rate?

In the late 1700s, Charles-Augustin de Coulomb ruled that a battery that receives a charge current of one ampere (1A) passes one coulomb (1C) of charge every second. In 10 seconds, 10 coulombs pass into the battery, and so on. On discharge, the process reverses. Today, the battery industry uses C-rate to scale the charge and discharge current of a battery.

Most portable batteries are rated at 1C, meaning that a 1,000mAh battery that is discharged at 1C rate should under ideal conditions provide a current of 1,000mA for one hour. The same battery discharging at 0.5C would provide 500mA for two hours, and at 2C, the 1,000mAh battery would deliver 2,000mA for 30 minutes. 1C is also known as a one-hour discharge; a 0.5C is a two-hour, and a 2C is a half-hour discharge.

The battery capacity, or the amount of energy a battery can hold, can be measured with a battery analyzer. The analyzer discharges the battery at a calibrated current while measuring the time it takes to reach the end-of-discharge voltage. An instrument displaying the results in percentage of the nominal rating would show 100 percent if a 1,000mAh test battery could provide 1,000mA for one hour. If the discharge lasts for 30 minutes before reaching the end-of-discharge cut-off voltage, then the battery has a capacity of 50 percent. A new battery is sometimes overrated and can produce more than 100 percent capacity; others are underrated and never reach 100 percent even after priming.

When discharging a battery with a battery analyzer capable of applying different C‑rates, a higher C‑rate will produce a lower capacity reading and vice versa. By discharging the 1,000mAh battery at the faster 2C, or 2,000mA, the battery should ideally deliver the full capacity in 30 minutes. The sum should be the same as with a slower discharge since the identical amount of energy is being dispensed, only over a shorter time. In reality, internal resistance turns some of the energy into heat and lowers the resulting capacity to about 95 percent or less. Discharging the same battery at 0.5C, or 500mA over two hours, will likely increase the capacity to above 100 percent.

To obtain a reasonably good capacity reading, manufacturers commonly rate lead acid at 0.05C, or a 20-hour discharge. Even at this slow discharge rate, the battery seldom attains a 100 percent capacity. Manufacturers provide capacity offsets to adjust for the discrepancies in capacity if discharged at a higher C‑rate than specified. Figure 1 illustrates the discharge times of a lead acid battery at various loads as expressed in C-rate.

Figure 1: Typical discharge curves of lead acid as a function of C-rate
Smaller batteries are rated at a 1C discharge rate. Due to sluggish behavior, lead acid is rated at 0.2C (5h) and 0.05C (20h).

While lead- and nickel-based batteries can be discharged at a high rate, a safety circuit prevents Li-ion with cobalt cathodes from discharging above 1C. Manganese and phosphate can tolerate discharge rates of up to 10C and the current threshold is set higher accordingly.

Comparing the Battery with other Power Sources

This article begins with the positive traits of the battery, and then moves into the limitations when compared with other power sources.

Energy storage
Batteries store energy well and for a considerable length of time. Primary batteries (non-rechargeable) hold more energy than secondary (rechargeable), and the self-discharge is lower. Alkaline cells are good for 10 years with minimal losses. Lead-, nickel- and lithium-based batteries need periodic recharges to compensate for lost power.

Specific energy (Capacity)
A laptop battery may hold adequate energy for portable use, but this does not transfer equally well for large mobile and stationary systems. For example, a 100kg (220lb) battery produces about 10kWh of energy — an IC engine of the same weight generates 100kW.

Responsiveness
Batteries have a huge advantage over other power sources in being ready to deliver on short notice — think of the quick action of the camera flash! There is no warm-up, as is the case with the internal combustion (IC) engine; the power from the battery flows within a fraction of a second. In comparison, a jet engine takes several seconds to gain power, a fuel cell requires a few minutes, and the cold steam engine of a locomotive needs hours to build up steam.

Power bandwidth
Rechargeable batteries have a wide power bandwidth, a quality that is shared with the diesel engine. In comparison, the bandwidth of the fuel cell is narrow and works best within a specific load. Jet engines also have a limited power bandwidth. They have poor low-end torque and operate most efficiently at a defined revolution-per-minute (RPM).

Environment
The battery runs clean and stays reasonably cool. Sealed cells have no exhaust, are quiet and do not vibrate. This is in sharp contrast with the IC engine and larger fuel cells that require noisy compressors and cooling fans. The IC engine also needs air and exhausts toxic gases.

Efficiency
The battery is highly efficient. Below 70 percent charge, the charge efficiency is close to 100 percent and the discharge losses are only a few percent. In comparison, the energy efficiency of the fuel cell is 20 to 60 percent, and the thermal engines is 25 to 30 percent. (At optimal air intake speed and temperature, the GE90-115 on the Boeing 777 jetliner is 37 percent efficient.)
Installation

The sealed battery operates in any position and offers good shock and vibration tolerance. This benefit does not transfer to the flooded batteries that must be installed in the upright position. Most IC engines must also be positioned in the upright position and mounted on shock- absorbing dampers to reduce vibration. Thermal engines also need air and an exhaust.

Operating cost
Lithium- and nickel-based batteries are best suited for portable devices; lead acid batteries are economical for wheeled mobility and stationary applications. Cost and weight make batteries impractical for electric powertrains in larger vehicles. The price of a 1,000-watt battery (1kW) is roughly $1,000 and it has a life span of about 2,500 hours. Adding the replacement cost of $0.40/h and an average of $0.10/kWh for charging, the cost per kWh comes to about $0.50. The IC engine costs less to build per watt and lasts for about 4,000 hours. This brings the cost per 1kWh to about $0.34. Read more about the Battery Against Fossil Fuel.

Maintenance
With the exception of watering of flooded lead batteries and discharging NiCds to prevent "memory," rechargeable batteries require low maintenance. Service includes cleaning of corrosion buildup on the outside terminals and applying periodic performance checks.

Service life
The rechargeable battery has a relatively short service life and ages even if not in use. In consumer products, the 3- to 5-year lifespan is satisfactory. This is not acceptable for larger batteries in industry, and makers of the hybrid and electric vehicles guarantee their batteries for 8 to 10 years. The fuel cell delivers 2,000 to 5,000 hours of service and, depending on temperature, large stationary batteries are good for 5 to 20 years.

Temperature extremes
Like molasses, cold temperatures slow the electrochemical reaction and batteries do not perform well below freezing. The fuel cell shares the same problem, but the internal combustion engine does well once warmed up. Charging must always be done above freezing. Operating at a high temperature provides a performance boost but this causes rapid aging due to added stress. Read about Discharging at High and Low Temperatures.

Charge time
Here, the battery has an undisputed disadvantage. Lithium- and nickel-based systems take 1 to 3 hours to charge; lead acid typically takes 14 hours. In comparison, filling up a vehicle only takes a few minutes. Although some electric vehicles can be charged to 80 percent in less than one hour on a high-power outlet, users of electric vehicles will need to make adjustments.

Disposal
Nickel-cadmium and lead acid batteries contain hazardous material and cannot be disposed of in landfills. Nickel-metal-hydrate and lithium systems are environmentally friendly and can be disposed of with regular household items in small quantities. Authorities recommend that all batteries be recycled.

IE9 Best Browser For Laptop Battery Life

IE 9 looks set to roll out to users via the Windows Update in late June and for many that could see improvements in their laptop battery life performance, at least that’s if the latest tests from Microsoft are true. Some may consider this a biased study since Microsoft carried out the tests, and inevitably IE came out on top.

However, I’m going to be the middle man in this case, and assume that the test was carried out fairly. Microsoft compared Internet Explorer 9, their latest browser with Opera 11, Firefox 4, Chrome 10 and Safari 5 on an Intel powered laptop. They then measure just how many watts the machine consumed with the browser idling, showing a news site and then running some graphic intensive web tasks.
The results? Well Internet Explorer came out as the most efficient web browser.


Obviously Microsoft were proud of this achievement, as IE 9 is said to be a big change from it’s predecessors, and that it is.toshiba laptop battery

However there is plenty of factors which could affect the result. The tests were carried out on a Windows 7 machine with an Intel chip, both of which Internet Explorer is designed to run best on. If you we’re to try Safari on the Mac, a platform which Safari is optimised to run on, I think you could find some different results.

Also the test sites that Microsoft used may not be ones anyone else would care to use and all laptops have different rates of power consumption, in fact there is an awful lot of variables in this test which aren’t factored in.

In fairness to Microsoft though, we appreciate you for caring about power consumption and the environment, and I’m sure we’d all love to have a bit of extra dell battery life from our laptops

Laptop Battery Is Indeed Too Good to Be True

The technology is actually quite fascinating. It’s a “betavoltaic” power source. These actually exist. And they work by getting together a lump of radioactive material battery(like tritium) that emits beta particles and then converting the beta particles to electricity. It’s just like photovoltaics…except instead of photons, it’s beta particles.

This device isn’t a battery, it’s actually a power source, and it will indeed continue producing power for 30 years (the half-life of tritium is 12 years, so it will be producing roughly 25% of its power 30 years from now.) But the article doesn’t point out that there are significant problems with the technology, specifically when using it as a laptop battery such as a dell laptop battery.

So what are the problems?
1. To power a laptop, you’d need about 50 lbs of tritium. Researchers plan on surmounting this by trickle charging a battery with the betavoltaic. This way, when the laptop is not in use, the battery would be recharged by the betavoltaic power source. But while using the laptop, you’d experience nothing more than an increase in life…not a 30 year battery.

2. While the article states that these laptops would run cooler than Li-ion laptops, that’s quite wrong. Betavoltaics lose about 75% of their energy as heat, and as designers will be required to include Li-ion batteries anyway, I imagine, if anything they’d be hotter.

3. At the end of its, life the power source would be completely innert, but during use, it wouldn’t be. Moderate shielding can easily block beta waves, but if the battery were damaged, and then you placed it on your “lap” I would hate to think of the consequnces. I’m not saying that this technology isn’t useful. In fact, it’s very useful, particularly for space missions requiring low but constant power. Or for any device that needs a low voltage for a long period of time and is difficult to access.

The possibility of trickle charging a Li-ion battery for increased life is intriguing, and certain low-power cell phones may someday be able to run 100% on betavoltaics. But a 30-year laptop battery, I’m afraid, doesn’t look likely.

Battery as a buffer

The main purpose of a stationary battery is to provide power during power outage. A battery bank can also provide supplementarypowerduring high-traffic periods. In essence, the battery acts as a buffer to assist the AC power supply when so needed. The term “AC power supply” refers to the unit that provides electrical power to the system and charges stationary batteries.

Cellular repeater towers are an example where the battery serves as a buffer to bridge heavy usage times. During off-peak periods, the toshiba batteries are fully charged, and at peak times when the load exceeds the capacity of the power supply, the batteries kick in to provide the extra power. A starter battery in a vehicle works in a similar way. While the motor is on idle at a traffic light, the battery complements the power to run the lights, windshield wipers and other accessories. Driving at highway speed replenishes the borrowed power.

When relying on the battery as buffer, make certain that the battery has enough time to charge between peak periods. The net charge must always be greater than what was drawn from the battery. Avoid deep discharges and make sure that the float charge voltage is set correctly. Stationary and starter batteries are not made for deep cycling. If excessively cycled, the dell laptop battery will experience unwanted stresses that will shorten the life.

Global battery markets

The battery market is expanding, and the global revenue in 2009 was a whopping $47.5 billion.* With the growing demand for portable electronics and the desire to connect and work outside the confines of four walls, experts predict that this figure will reach $74 billion in 2015. These numbers are speculative and include batteries for the electric powertrain of cars.

An Overview of Battery Types

Batteries are divided into two categories: primary and secondary. In 2009, primary batteries made up 23.6 percent of the global market. Frost & Sullivan (2009) predict a 7.4 percent decline of the primary battery in revenue distribution by 2015. Primary batteries are used in watches, electronic keys, remote controls, children’s toys, light beacons and military devices.

The real growth lies in secondary batteries. Frost & Sullivansay that rechargeable batteriesaccount for 76.4 percent of the global market, a number that is expected to increase to 82.6 percent in 2015. Batteries are also classified by chemistry and the most common are lithium-, lead-, and nickel-based systems. Figure 1 illustrates the distribution of these chemistries.

Figure 1: Revenue contributions by different battery chemistries

Courtesy of Frost & Sullivan (2009)

Lithium-ion is the battery of choice for consumer products, and no other systems threaten to interfere with its dominance at this time. The lead acid market is similar in size to Li-ion. Here the applications are divided into SLI (starter battery) for automotive, stationary for power backup, and deep-cycle for wheeled mobility such as golf cars, wheelchairs and scissor lifts. Lead acid holds a solid position, as it has done for the last hundred years. There are no other systems that threaten to unseat this forgiving and low-cost chemistry any time soon.

High specific energy and long storage has made alkaline more popular than carbon-zinc, which Georges Leclanché invented in 1868. The environmentally benign nickel-metal-hydride (NiMH) continues to hold an important role, as it replaces many applications previously served by nickel-cadmium (NiCd). However, at only three percent market share, NiMH is a minor player in the battery world and will likely relinquish more of its market to Li-ion by 2015.

Developing nations will contribute to future battery sales, and new markets are the electric bicycle in Asia and storage batteries to supply electric power to remote communities in Africa and other parts of the world. Wind turbines, solar power and other renewable sources also use storage batteries for load leveling. The large grid storage batteries used for load leveling collect surplus energy from renewable resources during high activity and supply extra power on heavy user demand. Read more about Batteries for Stationary, Grid Storage.

A major new battery user might be the electric powertrain for personal cars. However, battery cost and longevity will dictate how quickly the automotive sector will adopt this new propulsion system. Energy from oil is cheap, convenient and readily available; any alternative faces difficult challenges. Government incentives may be provided, but such intervention distorts the true cost of energy, shields the underlying problem with fossil fuel and only satisfies certain lobby groups through short-term solutions.

During the last five years or so, no new battery system has emerged that can claim to offer disruptive technology. Although much research is being done, no new concept is ready to enter the market at the time of writing, nor are new developments close to breakthrough point. There are many reasons for this apparent lack of progress: few products have requirements that are as stringent as the battery. For example, battery users want low price, long life, high specific energy, safe operation and minimal maintenance. In addition, the battery must work at hot and cold temperatures, deliver high power on demand and charge quickly. Only some of these attributes are achievable with various dell battery technologies.

Most consumers are satisfied with the battery performance on portable devices. Today’s battery technology also serves power backup and wheeled mobility reasonably well. Using our current battery technology for electric powertrains on cars, however, might prove difficult because the long-term effects in that environment are not fully understood. The switch to a power source offering a fraction of the kinetic energy compared to fossil fuels will be an eye-opener for motorists who continually demand larger vehicles with more. Read more about Batteries Against Fossil Fuel.

Advancements in Batteries

Batteries advance on two fronts, and these developments reflect themselves in increasedspecific energy for longer runtimes and improved pacific power for good power delivery on demand. Figure 2 illustrates the energy and power densities of lead acid, nickel-cadmium (NiCd), nickel-metal-hydride (NiMH) and the Li-ion family (Li-ion).

Figure 1-8: Specific energy and specific power of rechargeable batteries.Specific energy is the capacity a battery can hold in watt-hours per kilogram (Wh/kg); specific power is the battery’s ability to deliver power in watts per kilogram (W/kg).

Rechargeable lithium-metal batteries (Li-metal) were introduced in the 1980s, but instability with metallic lithium on the anode prompted a recall in 1991. Its high specific energy and good power density are challenging manufacturers revisit into this powerful chemistry again. Enhanced safety may be possible by mixing metallic lithium with tin and silicon. Experimental Li-metal batteries achieve 300Wh/kg, a specific energy that is of special interest to the electric vehicle. Read more about Experimental Rechargeable Batteries.

Use the AC power adapter switched on when the power is 96 ~ 100% or the battery removed from the machine

Using the AC power adapter, when the AC power plug to plug it into 220V ~ socket, while the power status indicator on the machine yet, gave the former (Note: During this period of about 5 seconds time), please press the power button to turn; dell Inspiron 9300 battery shutdown or go to sleep, in addition to green power status indicator lights have been extinguished all the other things, make a timely manner from 220V ~ unplug the AC power outlet plug, AC power plug pulled out after about 5 seconds, the green power status indicator light turns off ; (if necessary, may from time to unplug from the machine on AC power adapter's DC output plug, this time the battery will discharge through the AC power adapter reverse.) Otherwise the battery will overcharge and damage caused by the battery. Off state due to AC power adapter is still non-unloaded state, it will recharge the battery.

"With the power lithium-ion battery industry, more and more to high-end battery product development, in order to adapt to this change, the concept of battery manufacturers are also changing, lithium-ion battery production environment,IBM Thinkpad 290 Ac Adapter, IBM Thinkpad 365 Ac Adapter, IBM Thinkpad 390 Ac Adapter, IBM ThinkPad 600 Ac Adapter, IBM Thinkpad A20 Ac Adapter, IBM ThinkPad A21 Ac Adapter process support equipment, testing equipment, quality of management types of equipment needed, and so more and high-end. These domestic equipment companies to create a good market demand. "Beijing Sevenstar Electronics Co., Ltd.IBM Thinkpad 290 Ac Adapter, electronic automation equipment, general manager of King Road branch , said in an interview. In the field of lithium-ion battery, investment in equipment investment in fixed assets should be accounted for about 2 / 3 or more. To this end, domestic enterprises have increased the lithium-ion battery powered equipment in the field of investment.

Opportunities faced by domestic equipment
Lithium-ion battery manufacturing systems integrate key technologies

, equipment and product research process is to protect the safe operation of the battery pack important support conditions.

If the suspension of work in order to wait for the machine to enter, or suspend state, not from 220V ~ socket unplug the AC power plug; so when the machines still have the power to maintain. (Not recommended for a long time to make the dell Inspiron 9400 battery machine enters a wait or suspend state, in order to care for your machine.)

Double-check notebook CPU, hard drives, memory and other components, buy the best you can when you open the machine to go and see. In addition, we must guard against the use of second-hand books of the profiteers CPU desktop replacement notebook CPU despicable practice. Since the same frequency of the CPU general users will not notice, but the use of desktop CPU and notebook CPU is totally different, due to heat different issues, making CPU issue comes in the notebook can not shed heat, resulting in system does not stable. So in the process of buying as much as possible on-site inspection request to the CPU. For hard drives, due to visual observation can not understand the pros and cons of the hard disk, and only be detected by means of software, testing battery software available DM, NORTON and so on, through the DM, NORTON scanned, DM with a longer time, NORTON shorter time-consuming. Scanning process must be smooth uniform, if the cluster region which, when used too long, stating that the cluster region there must be problems. With regard to memory, second-hand laptop memory from 32M to 256M are, we should try to select more than 64M of memory, preferably more than 128M. Memory buy when to add a little, because some of the notebook computer's memory is rather special, and now long discontinued and can not reprovision. In addition, other houses, such as graphics card, we should also see a clear face to face.

It is understood that the production of lithium-ion toshiba battery materials, batteries need to prepare the main equipment, the battery pole piece manufacturing equipment, assembly equipment batteries, batteries charging and discharging and testing equipment. Apart from individual key equipment, the basic realization of the domestic. Shenzhen Ji Yang Yang as president of Automation Technology Co., Ltd. Kun said that the current equipment, the domestic lithium-ion battery technology is facing the rapid development of the historic opportunity to increase market capacity year after year, in the past 5 years, average annual growth in equipment demand 100% above. At the same time supporting the emergence of a group of domestic capacity lithium strong independent production companies to increase R & D efforts, and gradually have the level of independent research and advanced equipment to help speed up the lithium-ion battery equipment made the process to ensure the realization of lithium-ion cell manufacturing domestic innovation. "Equipment is the foundation of the industry, only the power lithium-ion battery lead in the development of equipment, and can we talk about the scale of production, can we talk about battery safety, consistency, efficiency, stability, and ultimately to achieve high-quality, low cost manufacturing objectives. "Yang Ru-Kun said. ACER travelmate 230 Battery ACER travelmate 240 Battery

Power is not fully depleted before (ie electricity in the 5-100%), not to recharge the battery, otherwise it will shorten the battery life.
When the power is 5 ~ 95% battery should be used, so the use of AC power adapter will charge the battery (charging side by side state).

4. When the power is 96 ~ 100% or the dell battery removed from the machine can use the AC power adapter switched on, use the AC power adapter AC power adapter when you please put the DC output plug on the plug into the machine, and then AC power plug to plug it into 220V ~ socket; removed when the AC power adapter should be first, and then unplug the AC power plug from the machine, unplug the AC power adapter DC output plug. Otherwise, they might damage your equipment

Get The Best Life Out of a Cell Phone Battery

In previous years, cell phone batteries had a better life if they were completely drained and then recharged completely. On most newer models this is no longer true.

If your phone does not have a full charge when you get it you will need to plug it in and charge it completely. This usually takes between two to four hours and will be indicated on most phones when the charge is complete.

2.When you are not using your phone, plug it in and charge it. It is best to try to plug it in every couple of hours and keep a consistent charge.

3.You can also plug your cell phone is with a car charger or even a computer charger so it doesn't run completely out of charge.

4.Texting and playing games on your cell phone will drain the battery faster. If you are running low on charge, moderate these cell phone activities.

Tips & Warnings

When purchasing a cell phone, ask your salesperson what the best procedure is for charging your phone. Every phone is different and someone with experience in the field is usually up to date on the new technology of cell phone batteries and charging.

Check your manual to see how long you will need to charge your battery.




How Long Do Cell Phone Batteries Last?
The exact amount of time cell phone batteries can last depends greatly on the amount of time the phone is talked on compared to the time it lies idle. Using the phone frequently consumes the battery at a much greater rate, and factors such as how often the battery is fully recharged are also very important.

Time Frame
Most phone batteries have an average talk time of two hours with a standby (idle) time of seven days.

History
The first widely used cell phones, which became mainstream in the 1990s, had an average life of 30 minutes of talk time and 24 hours of standby time.

Geography
A digital phone used in an area with analog service will drain its battery faster as it works to translate the analog signal. Searching for a signal in a no-service area will also drain the battery.

Warning
Some batteries might have their life shortened because they don't recharge fully due to a "memory effect," which causes them to only charge up to a certain level.

Prevention/Solution
The memory effect can be solved by allowing the nokia battery to completely discharge before completely charging it back up.

Rapid testing portable batteries

When studying the characteristics relating to battery state-of-health (SoH) and state-of-charge (SoC), some interesting and disturbing effects can be observed - the properties are cumbersome and not linear. Worst of all, the parameters are unique for every battery type. This inherent complexity makes it difficult to create a formula for rapid testing that works for all batteries.

In spite of these seemingly insurmountable odds, battery rapid testing is possible. But the questions are asked, how accurate will the test results be and how will the system adapt to different battery types. Instrument cost and ease-of-use are also concerns. This paper evaluates currently used methods, which include the load test, AC conductance test and the six-point test developed by Cadex.

The load test

The load test provides important battery information consisting of open battery voltage, voltage under load and internal resistance. nickel-based batteries should always indicate an open terminal voltage of about 1.1V/cell, even if empty. The electro-chemical reaction of the different metals in the cell generates this voltage potential. A depressed voltage may indicate high self-discharge or a partial electrical short.

A lead-based battery must always have a charge and the open terminal voltage should read 2.0V/cell and higher. If below 2 volts, a sulfation layer builds up that makes a recharge difficult, if impossible. An open terminal voltage of 2.10V/cell indicates that the battery is roughly 50% charged.

The voltage of a lithium-based battery can, to some extent, indicate SoC. A fully charged cell reads about 4.0V/cell and a partially charged cell measures between 3.0 and 4.0V/cell. The load test applies a momentary load, during which the voltage is measured. Voltage over current equals the resistance. More accurate results are obtained by applying a two-stage load. Figure 1 illustrates the voltage pattern of such a two-stage load test.

Figure 1: DC load test. The DC load test measures the battery's internal resistance by reading the voltage drops of two loads of different strength. A large drop indicates high resistance.

The AC conductance test

An alternative method of measuring the internal battery resistance is the AC conductance test. An alternating current of 50 to 1000 Hertz is applied to the battery terminals. The battery's reactance causes a phase shift between voltage and current, which reveals the condition of the hp pavilion dv6400 battery. AC conductance works best on single cells. Figure 2 demonstrates the relation of voltage and current on a battery.
Figure 2: AC load test. The AC method measures the phase shift between voltage and current. The battery's reactance and/or voltage deflections are used to calculate the impedance.

Some AC resistance meters evaluate only the load factor and disregard the phase shift information. This technique behaves similar to the pulse method in that the AC voltage is superimposed on the battery's DC voltage and acts as brief charge and discharge pulses. The amplitude of the ripple is utilized to calculate the internal battery resistance.

There are some discrepancies in the resistance readings between the 'load test' and 'AC conductance test'. The differences are more apparent on marginal than on good batteries. So which reading is correct? In many aspects, the AC conductance is superior to the load test, however, one single frequency cannot provide enough data to evaluate the battery adequately. Multi-frequency devices are being developed but their complexity rises exponentially with the number of frequencies used.

Resistance measurement, as a whole, provides only a rough sketch of the battery's performance because various battery conditions affect the readings. For example, a battery that has just been charged shows a higher resistance reading than one that has rested for a few hours. An empty or nearly empty battery also exhibits elevated internal resistance. To obtain reliable readings, a battery must be at least 50% charged.

Temperature further affects the internal resistance readings. A hot battery reads a lower resistance than one at ambient temperature or one that is cold. In addition, the chemistry, the number of cells connected in series and the current rating (size in mAh) of a battery influence the results. Many batteries also contain a protection circuit that further distorts the readings.

The Cadex QuickTest™

Cadex Electronics has developed a method to measure the state-of-health (SoH) of a hp compaq 381374-001 battery in 3 minutes. QuickTest™ uses a patent-pending inference algorithm to fuse data from 6 variables, which are: capacity, internal resistance, self-discharge, charge acceptance, discharge capabilities and mobility of electrolyte. The data is combined with a trend-learning algorithm to provide an accurate SoH reading in percent. Figure 3 illustrates general structure of such a network.

Figure 3: General structure of the Cadex QuickTest™ Multiple variables are fed to the micro controller, 'fuzzified' and processed through parallel logic. The information is averaged and weighted according to the battery application.

QuickTest™ is built into the Cadex C7000-Series battery analyzers and services nickel, lithium and lead-based batteries for two-way radios, cell phones, laptops, scanners and medical devices. The analyzers are user-programmable and also perform battery priming, reconditioning, fast-charging, life-testing and boosting functions.

QuickTest™ uses Pavilion dv3500 Series battery specific matrices that are obtained with the analyzer's trend learning process. The ability to learn allows adapting to new batteries in the field. The matrices are stored in the battery adapters and automatically configure the analyzer to the correct battery setting. The adapters commonly include the matrix at time of purchase. If missing, the matrix can be added in the field by scanning two or more batteries on the analyzer's Learn program. The required charge level to perform QuickTest™ is 20-90%. If outside this range, the analyzer automatically applies a brief charge or discharge.

What is the definition of state-of-health and when should a battery be replaced? SoH reveals the overall battery conditions based on the above mentioned variables, which are capacity, internal resistance, self-discharge, charge acceptance, discharge capabilities and mobility of electrolyte. If any of these variables provide marginal readings, the end result will be affected. A battery may have a good capacity but the internal resistance is high. In this case, the end SoH reading will be lowered accordingly. Similar demerit points are added if the battery has high self-discharge or exhibits other chemical deficiencies. The toshiba laptop battery should be replaced if the SoH falls below 80%.

How to Disassemble a Laptop Battery

Since buying a new laptop battery is so expensive, replacing the old cells inside a battery pack has become an attractive alternative for some laptop owners. Also, if the battery casing or housing becomes damaged, putting the good cells in a different battery housing can save a lot of money. Taking a laptop battery apart is not that difficult, and can be a fun learning experience for both children and adults.

1.Allow the battery to discharge. Turn off your laptop (if necessary), then remove the battery.

2.Pry open a small section of the battery pack seam with a screwdriver or craft knife. Continue to pry the case cover loose by moving around the edge until the entire top is free. This may take a bit of force. Lay the cover aside.

3.Carefully remove each HP compaq Pavilion dv3500 Series battery cell and its wire connectors using a craft knife and wire cutters. Each battery pack is different, but the cells are usually wrapped in a plastic casing with metal contacts attached to one end.

4.Put the cells, metal contacts, plastic casings, wires, and any other materials in a safe place if you plan to reuse them. Remove any adhesive residue or tape from the cells and metal contacts.

5.Remove any tape or screws that attach the circuit board to the battery housing, then lay it aside. Depending on the battery type, the circuit board may be attached to the cell pack, and not the battery housing. Clean any remaining residue from the plastic housing.

Tips & Warnings

If you decide to rebuild the HP compaq 381374-001 battery, watch it carefully while you charge for the first time. If the contacts are not connected properly, the battery may overheat and cause damage to the laptop.

How to transport batteries

Many battery types fall under strict transportation regulation. This is done for the safety of those handling them and the passengers traveling on a common carrier. Here are the rules in short.

Lead Acid

Most countries set strict rules for transporting lead acid batteries. Failure to comply with the regulations is a civil or criminal offense that can bring a stiff penalty on the carrier and/or shipper. The transport regulations require the following precautions.

• The vehicle transporting batteries can carry only one type of hazardous material. Brace the batteries securely to prevent damage and short circuits in transit. Non-hazardous goods on the same vehicle must be secured to prevent damaging the batteries.
   
• Batteries must be stacked upright, pole side outwards and placed on a wooden pallet. Place honeycomb cardboard between the layers and limit the stack to three layers on a single pallet. Wrap the package several times with shrink-wrap.
   
• Identify hazardous material with labels marked “Corrosive” using the appropriate symbols and colors. Stickers must conform to regulatory specifications.
   
• Mark all packages, i.e., batteries, wet, filled with acid, identification number (UN 2794).
   
• Provide a bill of lading document that includes the name of the company and shipper, contents of package, description of hazardous material and shipper’s certification.
   
• When shipping by air, restrict the weight per package to 25kg gross (55lb) on passenger air carriers. There is no limit on the number of packages per flight.

Different rules apply when shipping damaged batteries. A lead acid battery is considered damaged if there is a possibility of leakage due to a crack, or if one or more caps are missing. Transportation companies and air carriers may require that the batteries be drained of all acid prior to transport. Place damaged batteries in an acid-resistant container and add soda ash to neutralize any acid that might spill. Separate damaged and intact batteries.

Nickel-based Batteries

Nickel-based batteries have no transport limitations, however, some of the same precautions apply as for lead acid in terms of packaging to prevent electrical shorts and safeguard against fire. Regulations prohibit storing and transporting smaller battery packs in a metal box. If there is a danger of an electrical short, wrap each battery individually in a plastic bag. When carrying small batteries in your pocket, do not mix them with coins and house keys.

Lithium-based Batteries

In 2009, 3.3 billion Li-ion batteries were transported by air. Such air shipment is an ongoing concern, and an airline-pilot union has asked the Federal Aviation Administration (FAA) to ban them on passenger aircraft. From March 1991 to August 2010, batteries and battery-powered devices caused 113 recorded incidents with smoke, fire, extreme heat or explosion on passenger and cargo planes. The Portable Rechargeable Battery Association (PRBA) is aware of possible hazards and opposes any revisions in transportation rules, arguing that the restrictions would cost shippers and manufacturers billions of dollars.
PRBA is made up of major battery manufacturers, including Energizer, Panasonic, SAFT America, Sanyo and Varta Batteries. These manufacturers do not want to disrupt air shipments, especially batteries for critical medical and military missions. They argue that the batteries causing problems do not meet US hazardous material handling regulations and ask the FAA to enforce stricter manufacturing rules. The manufacturers tell the aviation industry further that, as a result of the well-publicized 2006 recall, a safer generation of Li-ion batteries has emerged. According to U.S. Census Bureau (2010), airfreight transports roughly 364 million cell phones, 142 million cameras and 47 million laptops as part of just-in-time delivery to stores. No deaths and only 26 injuries are attributed to shipping billions of lithium batteries every year.
The estimated failure rate of Li-ion is one per 10 million. Examining the 113 recorded incidents of transporting batteries by air in 19 years reveals that most failures occurred due to inappropriate packaging or handling, which caused damage or electrical short. Most incidents happened at airports or in cargo hubs. Problem batteries include primary lithium (lithium-metal), lead, nickel and alkaline systems, and not just lithium-ion, as is perceived. Newer consumer products have very few surprise failures caused by Li-ion batteries.
There are, however, restrictions with lithium-ion batteries on airplanes and travelers are reminded how many batteries can be carried on board in portable devices and as spare packs. Since January 2008, people can no longer pack spare lithium batteries in checked baggage, but airlines allow them as carry-on. The passenger compartment enables better safety monitoring with access to fire extinguishers. In one incident, a coffee pot served as extinguishing device for a flaming laptop battery on board of a plane. This would be impossible in the cargo bay below.
In terms of transportation, lithium-based batteries are divided into non-rechargeablelithium-metal batteries that are typically used in film cameras, and the rechargeable lithium-ion battery found in cell phones and laptops. Airlines allow both types as carry-on either installed or carried as spare packs as long as they don’t exceed the following limitation of lithium or equivalent of:

• 2 grams for primary lithium batteries
   
• 8 grams for a secondary lithium-ion. This amounts to a 100Wh battery.
   
• 25 grams for all Li-ion combined. This amounts to 300Wh worth of Li-ion batteries.

The lithium content of the primary lithium batteries is often printed on the label. Li-ion, on the other hand, has no metallic lithium and uses the equivalent lithium content (ELC) instead. To calculate the ELC, multiply the rated capacity (Ah) times 0.3. As an example, a 1Ah cell has 0.3 grams of lithium. The 8-gram ELC limitation allows a 100Wh battery.
A laptop battery commonly uses 2Ah cells containing 0.6 grams of ELC each. The battery pack may have eight cells (4 in series; 2 in parallel), which brings the ELC to 4.8 grams, well below the 8-gram limit allowed by a single pack. To derive the watt-hour, multiply the battery voltage by the ampere-hours (Ah). The battery in question has a voltage of 14.40V (4 x 3.6V) and a rating of 4Ah (2 x 2A). In summary, 14.4 x 4 = 57.6Ah, or roughly 60Wh.
While regulations limit the Li-ion battery to no larger than 100Wh, each passenger and travel companion is allowed to carry spare packs of up to 25 grams of ELC, or 300Wh. The airlines recommend placing each battery in a clear plastic bag or covering the contacts with a tape to prevent an electric short. Although current rules forbid passengers from carrying lithium-ion batteries in checked luggage, devices with non-removable batteries, such as the iPhone, iPad and certain brand of laptops, are exempt from the rules.
 Anyone shipping lithium-ion batteries in bulk must meet transportation regulations and this applies to domestic and international shipments by land, sea and air. Lithium-ion cells whose equivalent lithium content exceeds 1.5 grams or 8 grams per battery pack (100Wh) must be shipped as “Class 9 miscellaneous hazardous material.” Film crew often carry larger batteries for professional video cameras, and these are handled as hazardous material. If a shipment in the US contains more than 24 lithium cells or 12 lithium-ion packs, special markings and appropriate shipping documents are required. Each package must be clearly marked to inform the airline that lithium batteries are involved. Open cells and packs must be separated to prevent electrical short. The packages must be strong to allow stacking.

Frequently Asked Questions about Transporting Lithium Ion Batteries by Air

• Must consumer-type lithium ion batteries always be shipped as Class 9 dangerous good?

No. Almost all small Li-ion (less than 100Wh) in consumer products are except from dangerous goods regulations and do not require Class 9 labeling, marking or packaging.

• In what quantities can lithium ion batteries be shipped?

Lithium ion asus a32-f5 battery can be shipped in small and large quantities. A single package may contain as few as five batteries, while a pallet may contain more than 1,000 packs.

• Why do some packages of Li-ion batteries contain a "Caution" marking and include shipping papers when most consumer lithium ion batteries are except from regulation?

In the US, the marking is mandatory for packages of more than 24 Li-ion cells or 12 Li-ion packs. The documents identify the goods and tell what to do if the package is damaged.

• Must lithium ion batteries be tested according to the UN Manual of Tests and Criteria?

Yes, all Li-ion cells and packs shipped internationally must be tested. In the US, UN testing also includes small, consumer-size lithium ion cells and packs. Read about Building a Lithium-ion Pack.

To assure lithium-based batteries are designed and packaged to withstand transportation conditions, the US Department of Transportation (DOT) proposes new regulations. While the Airline Pilots Association supports tighter restrictions and has called for lithium batteries to be “fully regulated dangerous goods” as airline cargo, PRBA recommends dropping the proposed rules in favor of the International Civil Aviation Organization requirement (ICAO), which has been in effect since 2009 but was never applied in the US. Industry lobbyists say that the government has enough rules to ensure safe toshiba pa3399u-1bas battery shipments and express concern that some shippers do not follow packaging requirements. They recommend stronger enforcements there.

Proposed changes by the US Department of Transportation (DOT

• Mandate that all batteries pose a hazard when transported.
   
• Mandate transport documentation to accompany a shipment of small lithium batteries, including notifying the pilot of the location of Li-ion being shipped on the aircraft.
   
• Require manufacturers to retain UN-specified tests for all lithium battery types transported.
   
• Make cargo locations accessible to crew, place cargo in locations equipped with an FAA-approved fire suppression system, or transport cargo in an FAA-approved container.
   
• Adopt watt-hours formula in place of equivalent lithium content.
   
• Put Li-ion not exceeding 100Wh in inner package of 10kg (22lb) limit; attach caution label.
   
• Divert the transportation of defective or damaged batteries to highway, rail and boat. 

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