And the battery's long life may outweigh any lack in the energy-density

July 09 [Tue], 2013, 10:25
A new lithium ion battery technology may finally make the devices cheap enough and durable enough to turn electric cars from a niche product into a mass-market mode of transport. Waltham, Mass.–manufacturer A123 A32-F52 laptop battery Systems has produced a cell that delivers 20 percent more power, works at temperatures as low as –30 degrees Celsius and as high as 60 degrees C, and should be just as easy as current batteries to manufacture.

"There's no 'unobtainium' in this battery," says company co-founder, Massachusetts Institute of Technology materials scientist Yet-Ming Chiang. "It's not based on a very expensive new chemistry."

Independent scientists have been scrutinizing the company's claims and say they are impressed. From the few details the company will reveal, the new battery, known as the Nanophosphate EXT, appears to be based on the exact same lithium–iron phosphate chemistry found in other A123 batteries that appear everywhere from electronics to hybrid electric buses, but with improved properties.

The improved power and expanded temperature range suggest that A123 scientists have improved the way that electrons and ions shuffle through the battery system. "The ions and electrons have to move faster," explains chemist Jeffrey Chamberlain, who leads the Energy Storage Initiative at Argonne National Laboratory and was not involved in this research. That, in turn, suggests an improvement in one of three places: the electrolyte (the ion-carrying guts of the battery); the interface between the electrolyte and the electrodes (the charge-collecting plates); the electrodes themselves; or all of the above. Manufacturing innovations may also contribute. Although the specifics of the Nanophosphate EXT improvements remain unclear, A123 does hold patents relating to work on novel electrode and electrolyte materials as well as battery structures. "If this is real, it's a major breakthrough," Chamberlain adds.

A123's internal results have been independently verified by the Center for Automotive Research at The Ohio State University. "We perceive only positive characteristics for this remarkable technology," says O.S.U. mechanical engineer Yann Guezennec, who led testing of the new cell. Those characteristics include charge/discharge cycle-lives at least twice as long as a competitor "currently in use in a vehicle that is on the road today," says A123 spokesman Dan Borgasano, and 10 times longer than existing lead–acid batteries.

One downside is that A123's iron phosphate technology only offers roughly 160 watt-hours per kilogram, an energy density less than some other lithium ion technologies (not to mention liquid fuels like gasoline). On the plus side, it is not prone to bursting into flame, as some lithium cells are. "One big benefit of A32-F82 laptop battery iron phosphate is its stability and safety," Chamberlain says. "Things you find in nature when you dig up dirt tend to be pretty stable."

And the battery's long life may outweigh any lack in the energy-density department; it retains 90 percent of its capacity even after 2,000 chargings and dischargings. The batteries in current electric cars, on the other hand, fade over time, requiring car manufacturers to include batteries that are bigger than necessary. Plus, A123's new battery can be air-cooled rather than liquid-cooled, thanks to its wide temperature range, offering savings in both cost and weight.

This enables moderate to heavy loads and is ideal for digital cameras

July 09 [Tue], 2013, 10:23
Rechargeable batteries are gaining such high media attention that some consider non-rechargeables as old technology. Primaries still play an important role, especially when charging is impractical or impossible such as in military combat, rescue missions and forest-fire services. Other applications for primaries are pacemakers for heart patients, tire pressure gauges in cars and trucks, transmitters for A32-F80 laptop battery bird tracking, intelligent drill bits in mining, light beacons in oceans, not to forget our wristwatches, remote controls, electric keys and children’s toys. High specific energy, long storage times and instant readiness give the primary battery a unique advantage over other power sources. Primary batteries are generally inexpensive, readily available and environmentally friendly.

Carbon-zinc, also known as the Leclanché battery, is one of the least expensive primary batteries and often comes with consumer devices when the batteries are included. Alkaline-manganese, known as Alkaline, is an improved version of the old carbon-zinc. Lewis Urry invented it in 1949 while working with the Eveready Battery Company Laboratory in Parma, Ohio. Alkaline delivers more energy at higher load currents than carbon-zinc and does not leak when depleted, although it is not totally leak-proof. A discharging Alkaline generates hydroxide gases. Pressure buildup can rupture the seal and cause corrosion in form of a feathery crystalline structure that can spread to neighboring parts and cause damage. All primary batteries produce gas on discharge and the portable device must have provision for venting.

Lithium Iron Disulfide (Li-FeS2) is a newcomer to the primary battery family and offers improved performance. Lithium batteries normally deliver 3 volts and higher, but Li-FeS2 produces 1.5 volts to be compatible with the AA and AAA formats. It has a higher capacity and a lower internal resistance than Alkaline. This enables moderate to heavy loads and is ideal for digital cameras. Further advantages are improved low temperature performance, superior leakage resistance and low self-discharge, allowing 15 years of storage at ambient temperatures. Low weight and minimal toxicity are added benefits.

Litium Iron Disulfide is a newcomer to the primary battery family and offers improved performance.Lithium batteries normally deliver 3 volts and higher ,but Li-FeS2
prodduces 1.5 volts to be compatible A32-1015 laptop battery with the AA and AAA formats.It has a higher capacity and a lower internal resistance than



The disadvantages of the Li-FeS2 are a higher price and transportation issues because of the lithium metal content in the anode. This causes restriction in air shipment. In 2004, the US DOT and the Federal Aviation Administration (FAA) banned bulk shipments of primary lithium batteries on passenger flights, but airline passengers can still carry them on board or in checked bags. Each AA-sized Li-FeS2 contains 0.98 grams of lithium; the air limitation of primary lithium batteries is 2 grams (8 grams for rechargeable Li-ion). This restricts each passenger to two cells but exceptions have been made in which 12 sample batteries can be carried.

Li-ion with high energy densities are reserved for consumer products

May 21 [Tue], 2013, 10:34
New hydride alloys discovered in the 1980s offered better stability and the development of NiMH advanced in earnest. Today, NiMH provides 40 percent higher specific energy than a standard NiCd, but the decisive advantage i L08O6C02 cheaps the absence of toxic metals.

The advancements of NiMH are impressive. Since 1991, the specific energy has doubled and the life span extended. The hype of lithium-ion may have dampened the enthusiasm for NiMH a bit but not to the point to turn HEV makers away from this proven technology. Batteries for the electric powertrain in vehicles must meet some of the most demanding challenges, and NiMH has two major advantages over Li-ion here. These are price and safety. Makers of hybrid vehicles claim that NiMH costs one-third of an equivalent Li-ion system, and the relaxation on safety provisions contribute in part to this price reduction.

Nickel-metal-hydride is not without drawbacks. For one, it has a lower specific energy than Li-ion, and this is especially true with NiMH for the electric powertrain. The reader should be reminded that NiMH and Li-ion with high energy densities are reserved for consumer products; they would not be robust enough for the hybrid and electric vehicles. NiMH and Li-ion for the electric powertrain have roughly one-third less capacity than consumer batteries.

NiMH also has high self-discharge and loses about 20 percent of its capacity within the first 24 hours, and 10 percent per month thereafter. Modifying the hydride materials lowers the self-discharge and reduces corrosion o 43R1967 cheapf the alloy, but this decreases the specific energy. Batteries for the electric powertrain make use of this modification to achieve the needed robustness and life span.

There are strong opinions and preferences between battery chemistries, and some experts say that NiMH will serve as an interim solution to the more promising lithium systems. There are many hurdles surrounding Li-ion also and these are cost and safety. Li-ion cells are not offered to the public in AA, AAA and other popular sizes in part because of safety. Even if they were made available, Li-ion has a higher voltage compared to nickel-based batteries.

AGM batteries are commonly built to size

May 21 [Tue], 2013, 10:29
AGM technology was developed in 1985 for military aircraft to reduce weight, increase power handling and improve reliability. The acid is absorbed by a very fine fiberglass mat, making the battery spill-proof. This enables shipment 51J0497 cheapwithout hazardous material restrictions. The plates can be made flat to resemble a standard flooded lead acid pack in a rectangular case; they can also be wound into a cylindrical cell.

AGM has very low internal resistance, is capable to deliver high currents on demand and offers a relatively long service life, even when deep-cycled. AGM is maintenance free, provides good electrical reliability and is lighter than the flooded lead acid type. It stands up well to low temperatures and has a low self-discharge. The leading advantages are a charge that is up to five times faster than the flooded version, and the ability to deep cycle. AGM offers a depth-of-discharge of 80 percent; the flooded, on the other hand, is specified at 50 percent DoD to attain the same cycle life. The negatives are slightly lower specific energy and higher manufacturing costs that the flooded. AGM has a sweet spot in midsize packs from 30 to 100Ah and is less suitable for large UPS system.

AGM batteries are commonly built to size and are found in high-end vehicles to run power-hungry accessories such as heated seats, steering wheels, mirrors and windshields. NASCAR and other auto racing leagues choose AGM products because they are vibration resistant. AGM is the preferred battery for upscale motorcycles. Being sealed, AGM reduces acid spilling in an accident, lowers the weight for the same performance and allows installation at odd angles. Because of good performance at cold temperatures, AGM batteries are also used for marine, motor home and robotic applications.

Ever since Cadillac introduced the electric starter motor in 1912, lead acid became the natural choice to crank the engine. The classic flooded type is, however, not robust enough for the start-stop function and most batteries in a micro-hybrid car are AGM. Repeated cycling of a regular flooded type causes a sharp capacity fade after two years of use. See Heat, Loading and Battery Life.

As with all gelled and sealed units, AGM batteries are sensitive to overcharging. These batteries can be charged to 2.40V/cell (and higher) without problem; however, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages). Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell), and a 51J0499 cheapdirect replacement with a sealed unit could spell trouble by exposing the battery to undue overcharge on a long drive. See Charging Lead Acid.

AGM and other sealed batteries do not like heat and should be installed away from the engine compartment. Manufacturers recommend halting charge if the battery core reaches 49°C (120°F). While regular lead acid batteries need a topping charge every six months to prevent the buildup of sulfation, AGM batteries are less prone to this and can sit in storage for longer before a charge becomes necessary. Table 1 spells out the advantages and limitations of AGM.

In terms of appearance it is a white and free flowing powder

February 19 [Tue], 2013, 15:13
If you drove 211 miles north of Las Vegas off the I-95 you would come to a small town called Goldfield, Nevada. It is a very small town whose population counts at the 2000 census was only 440 people. What makes Goldfield very 6 cell Vostro 1400 important to the US and the world is its close proximity to Silver Peak Nevada (home of 80 full time residents). Silver Peak is home to Chemetall Foote Corporation's local lithium mine, the area's largest employer and the only lithium producing mine in the United States.

Chemetalls’s net sales from mining operation are just over $1 Billion. Not too shabby! In August of 2009 Chemetall was awarded $28.4 million in the Federal Recovery and Reinvestment Act funds to expand and upgrade the production of lithium materials for advanced transportation batteries. The funds will be used by Chemetall in part to expand and upgrade the production of lithium carbonate at the company’s Silver Peak, Nevada, site. Again it should be noted that Chemetall is the only U.S. domestic source of lithium raw material and the largest global producer of lithium and lithium compounds used in batteries, pharmaceuticals and many other industries. Chemetall is a very important partner in the U.S., economy due to the fact that over the past 7 years about 2.4 Billion batteries are in use and are utilizing approximately 35 million pounds of battery grade lithium.

So what is standard battery grade lithium? Standard battery grade lithium is a lithium carbonate manufactured for solid ion conductors and monocrystals used in the electronics industry. Such carbonate is a source of a raw material for the production of cathode material used in lithium ion batteries (lithium cobalt oxide, lithium manganese oxide).

In terms of its chemical composition standard battery grade lithium, or Lithium bis-(oxalato)borate – LiBOB. LiBOB is a conductive agent for the use in high performance lithium (Li) batteries and lithium ion (Li-ion) batteries and lithium polymer (Li-po) batteries.

In terms of appearance it is a white and free flowing powder. It’s chemical formula is C4BO8Li. Its molecular weight is 193.79 g/mol. Its density is 0,8 - 1,2 g/ccm (at 20°C). Its thermal stability is decomposition > 290°C; hygroscopic; decomposes slowly on contact with water. Its solubility is 17 % in propylene carbonate (25°C) about 35 wt.-% in water; (hydrolysis) good solubility in carbonate mixtures, carboxylic esters, glymes, ketones, and lactones.

A chemical analysis reveals that C4BO8Li is 97.4% assay (a procedure for measuring the molecular structure of an organic sample); 0.03% water; 2.5% insolubles; 10 ppm of Cyanoacrylate; 10 ppm of Iron; 20 ppm of Sodium; 20 ppm of Chlorine.

So how important is C4BO8Li and is there enough available resource? Current available lithium reserves is estimated at 28,000,000 6 cell KM742 tonnes. Current worldwide demand is estimated at 23,000,000 tonnes. So there is enough no and for the foreseeable future as long as mines like the Silver Peak mine in Nevada continues to operate.

Include a temperature sensor that disrupts the current on high heat

February 19 [Tue], 2013, 15:11
Batteries for power tools and other industrial devices can often be repaired by replacing one or all cells. Finding a NiCd and NiMH cell is relatively easy; locating the correct Li-ion cell can be more difficult. Naked Li-ion cells are not readily available off the shelf and a reputable battery manufacturer may only sell to 6 cell Inspiron-1320 certified pack assemblers. Incorrect use or lack of an protection circuit could cause stress and disintegration of the replaced cell. When repairing a Li-ion pack make certain that each cell is properly connected to a protection circuit. Read about Safety Concerns and Protection Circuits.

If a relatively new pack has only one defective cell, you may replace only the affected cell. On an aged battery, it’s best to replace all cells. Adding a new cell with full capacity in between neighboring cells that have faded would cause a cell mismatch. Matching the replacement cell with one of a lower rating may work but this fix is often of short duration. Always replace with the same chemistry cell.

A well-matched battery pack means that all cells have similar capacities. An anomaly can be drawn with a chain in which the weakest link determines the performance of the battery. Read more about Can Batteries Be Restored?.

When replacing all cells, the rating is less important as long as the differences are not too large for the charger to handle. Cells with higher Ah will simply take a bit longer to charge. The state-of-charge of all cells being charged for the first time should have a similar charge level, and the open-circuit voltages should be within 10 percent of each other

Many visitors of BatteryUniversity.com ask if NiCd can be replaced with NiMH? Theoretically, this should be possible but charging may be an issue. NiMH uses a more defined charge algorithm than NiCd. A modern NiMH charger can charge both NiMH and NiCd; the old NiCd charger could overcharge NiMH by not properly detecting full charge state and applying a trickle charge that is too high.

Welding the cells is the only reliable way to get dependable connection. Limit the heat transfer to the cells during welding to prevent excess heat buildup.
Simple Guidelines when Repairing Battery Packs
Only connect cells that are matched and have the identical state-of-charge. Do not connect cells of different chemistry, age or capacity.

Never charge or discharge Li-ion batteries without a working protection circuit unattended. Each cell must be monitored individually.

Include a temperature sensor that disrupts the current on high heat.

Apply a slow charge only if the cells have different state-of-charge.

Pay special attention when using an unknown brand of cells. Some may not contain a high level of intrinsic safety.

Li-ion is sensitive to reverse 6 cell Vostro 1710 batterypolarization. Observe correct polarity.

Do not charge a Li-ion battery that exhibits physical damage or has dwelled at a voltage of less than 1.5V/cell.

When repairing Li-ion, assure that each cell is connected to a protection circuit.

Your battery will still be useful when you're looking for a new laptop

December 18 [Tue], 2012, 11:05
This isn't, strictly speaking, the case. You can't make old lithium hold more electrons than it can currently manage.

But if the battery is running out unexpectedly fast, or if your laptop is having trouble figuring out how much power it has left, youbuy Vostro 1310 battery might be able to fix the battery's "gas gauge," so it at least gives a more accurate reading.

If you suspect the battery can't tell if it's charged or not, run it through a couple of cycles. Drain it of all its power (yes, this is the exception to the "don't drain the battery" rule mentioned above), recharge it to 100 percent, and then repeat.

But how do you drain the battery when Windows won't let you do just that? Don't bother with the settings described above. They're not safe (you might forget to change them back), they may not be getting an accurate reading, and they quite possibly won't let you set the critical battery level to 0 percent. (If they did, it would crash Windows.)

Instead, unplug your AC power and keep your laptop running (you can work on it if you like) until it automatically hibernates. Then reboot your PC back and go directly to the system setup program.

I can't tell you exactly how to get there; each computer is different. Turn on your PC and look for an onscreen message (one of the first you'll see) that says something like "Press the X key for setup." Immediately press the designated key.

It may take a couple of times to get the timing right. If there isn't enough power to let it boot, plug in AC until you're at the setup program, then unplug it.

Leave the notebook on until it shuts off. This can take some time (45 minutes on my laptop); setup uses a lot less power than Windows.

Once the PC is off, plug in the AC power, then wait a few hours before rebooting to Windows and making sure you've got a full6cells Inspiron 1750 battery recharge.

Repeat the process once or twice.

With luck and proper care, your battery will still be useful when you're looking for a new laptop.

Some people recommend you store it in the refrigerator

December 18 [Tue], 2012, 11:03
Laptop batteries are like people--eventually and inevitably, they die. And like people, they don't obey Moore's Law--You can't expect next year's batteries to last twice as long as this year's. Battery technology may improve a bit over time (after all, there's plenty of financial incentive for better batteries), but, while Brand new rn873 Studio 1555 batteryinteresting possibilities may pop up, don't expect major battery breakthroughs in the near future.

Although your battery will eventually die, proper care can put off the inevitable. Here's how to keep your laptop battery working for as long as possible. With luck, it could last until you need to replace that aging notebook (perhaps with a laptop having a longer battery life).

I've also included a few tips on keeping the battery going longer between charges, so you can work longer without AC power.


Squeezing every drop of juice out of a lithium ion battery (the type used in today's laptops) strains and weakens it. Doing this once or twice won't kill the battery, but the cumulative effect of frequently emptying your battery will shorten its lifespan.

(There's actually an exception to this rule--a circumstance where you should run down the battery all the way. I'll get to that later.)

The good news: You probably can't run down the battery, anyway--at least not without going to a lot of trouble to do so. Most modern laptops are designed to shut down before the battery is empty.

In fact, Vista and Windows 7 come with a setting for just this purpose. To see it, click Start, type power, and select Power Options. Click any one of the Change plan settings links, then the Change advanced power settings link. In the resulting dialog box, scroll down to and expand the Battery option. Then expand Critical battery level. The setting will probably be about 5 percent, which is a good place to leave it.

XP has no such native setting, although your laptop may have a vendor-supplied tool that does the same job.

Myth: You should never recharge your battery all the way.

There's considerable controversy on this point, and in researching this article I interviewed experts both for and against. But I've come down on the side of recharging all the way. The advantages of leaving home with a fully-charged battery--you can use your PC longer without AC power--are worth the slight risk of doing damage.

Keep It Cool

Heat breaks down the battery, and reduces its overall life.

When you use your laptop, make sure the vents are unblocked. Never work with the laptop on pillows or cushions. If possible, put it on a raised stand that allows for plenty of airflow.

Also, clean the vents every so often with a can of compressed air. You can buy this for a few dollars at any computer store. Be sure to follow the directions on the can, and do this only when the notebook is off.

Give It a Rest

If you're going to be working exclusively on AC power for a week or more, remove the battery first.

Otherwise, you'll be wearing out the battery--constantly charging and discharging it--at a time when you don't need to use it at all. You're also heating it up (see "Keep It Cool," above).

You don't want it too empty when you take it out. An unused battery loses power over time, and you don't want all the power to drain away, so remove it when it's at least half-charged.

Never remove the battery while the computer is on, or even in standby or sleep mode; doing so will crash your system and possibly damage your hardware. Even inserting a battery into a running laptop can damage the system. So only remove or reinsert the battery when the laptop is completely off or hibernating.

If you've never removed your laptop's battery and don't know how, check your documentation. (If you don't have it, you can probably find it online.) The instructions generally involve turning the laptop upside-down and holding down a button while you slide out the battery.

Myth: Refrigerate your battery.

Some people recommend you store it in the refrigerator, inside a plastic bag. While you should keep a battery cool, the last thing you want is a wet battery, and condensation is a real danger in the fridge. Instead, store it in a dry place at room temperature. A filing cabinet works fine.

You don't want the battery to go too long without exercise or let it empty out entirely. If you go without the battery for more thanreplacement rn873 RM791 two months, put it in the PC and use it for a few hours, then remove it again.

Also, before you take the laptop on the road, reinsert the battery and let it charge for a few hours before unplugging the machine. Allow the battery time to get a full charge before you remove the AC power.

A strong arm resembling a good battery remains firm

October 29 [Mon], 2012, 14:46
With the large number of lithium-ion batteries in use and the population growing rapidly, developing an effective testing method has become an urgent task. QuickSort™ (Cadex) is a further development of QuickTest™ using a generic matrix. The simplification was made possible by limiting the battery population Dell Vostro 1400 laptop batteryto single-cell Li-ion from 500 to 1,500mAh. (Larger cells and higher voltages will need a different generic matrix.) Rather than capacity readout in percentage, QuickSort™ classifies the battery health as Good, Low or Poor.

Electrochemical dynamic response,the method used for QuickSort™, measures the mobility of ion flow between the electrodes on a digital load. The response can be compared with a mechanical arm under load. A strong arm resembling a good battery remains firm, and a weak arm synonymous to a faded battery bends and becomes sluggish under load. Figure 1 illustrates the concept of the technology.

With the large number of lithium-ion batteries in use and the population growing rapidly, developing an effective testing method has become an urgent task. QuickSort™ (Cadex) is a further development of QuickTest™ using a generic matrix. The simplification was made possible by limiting the battery population to single-cell Li-ion from 500 to 1,500mAh. (Larger cells and higher voltages will need a different generic matrix.) Rather than capacity readout in percentage, QuickSort™ classifies the dell rn873 battery KM742 health as Good, Low or Poor.

Electrochemical dynamic response,the method used for QuickSort™, measures the mobility of ion flow between the electrodes on a digital load. The response can be compared with a mechanical arm under load. A strong arm resembling a good battery remains firm, and a weak arm synonymous to a faded battery bends and becomes sluggish under load. Figure 1 illustrates the concept of the technology.

The lithium-ion battery works on ion movement between the positive

October 29 [Mon], 2012, 14:41
The lithium-ion battery works on ion movement between the positive and negative electrodes. In theory such a mechanism should work forever, but cycling, elevated temperature and aging decrease the performance over time. SinceAcer AS10D51are used in demanding environmental conditions, manufacturers take a conservative approach and specify the life of most Li-ion between 300 and 500 discharge/charge cycles.

Counting cycles is not conclusive because a discharge may vary in depth and there are no clearly defined standards of what constitutes a cycle. Read more about What Constitutes a Discharge Cycle?. In lieu of cycle count, some batteries in industrial instruments are date-stamped, but this method is not reliable either because it ignores environmental conditions. A battery may fail within the allotted time due to heavy use or unfavorable temperature conditions, but most quality packs will last considerably longer than what the stamp indicates.

The performance of a battery is measured in capacity, a leading health indicator. Internal resistance and self-discharge also play a role but with modern Li-ion these carry lower significance in predicting the end-of-battery-life. Figure 1 illustrates the capacity drop of 11 Li-polymer batteries that have been cycled at a Cadex laboratory. The 1500mAh pouch cells for smartphones were first charged at a current of 1500mA (1C) to 4.20V/cell and allowed to saturate to 0.05C (75mA) as part of the full charge procedure. The batteries were then discharged at 1500mA to 3.0V/cell, and the cycle was repeated.

The lithium-ion battery works on ion movement between the positive and negative electrodes. In theory such a mechanism should work forever, but cycling, elevated temperature and aging decrease the performance over time. Since batteries are used in demanding environmental conditions, manufacturers take a conservative approach and specify the life of most Li-ion between 300 and 500 discharge/charge cycles.

Counting cycles is not conclusive because a discharge may vary in depth and there are no clearly defined standards of what constitutes a cycle. Read more about What Constitutes a Discharge Cycle?. In lieu of cycle count, some batteries in industrial instruments are date-stamped, but this method is not reliable either because it ignores environmental conditions. A battery may fail within the allotted time due to heavy use or unfavorable temperature conditions, but most quality packs will last considerably longer than what the stamp indicates.

The performance of a battery is measured in capacity, a leading health indicator. Internal resistance and self-discharge also play a role but with modern Li-ion these carry lower significance in predicting the end-of-battery-life. Figure 1 illustrates the capacity drop of 11 Li-polymer batteries that have been cycled at a Cadex laboratory. The 1500mAh pouch cells for smartphones were first charged at a current of 1500mA (1C) to 4.20V/cell and allowed to saturate to 0.05C (75mA) as part of the full charge procedure. The batteries were then discharged at 1500mA to 3.0V/cell, and the cycle was repeated.

The lithium-ion battery works on ion movement between the positive and negative electrodes. In theory such a mechanism should work forever, but cycling, elevated temperature and aging decrease the performance over time. Since batteries are used in demanding environmental conditions, manufacturers take a conservative approach and specify the life of most Li-ion between 300 and 500 discharge/charge cycles.

Counting cycles is not conclusive because a discharge may vary in depth and there are no clearly defined standards of what constitutes a cycle. Read more about What Constitutes a Discharge Cycle?. In lieu of cycle count, some batteries in industrial instruments are date-stamped, but this method is not reliable either because it ignores environmental conditions. A battery may fail within the allotted time due to heavy use or unfavorable temperature conditions, but most quality packs will last considerably longer than what the stamp indicates.

The performance of a battery is measured in capacity, a leading health indicator. Internal resistance and self-discharge also play a role but with modern Li-ion these carry lower significance in predicting the end-of-replacement battery for Inspiron 1521 battery-life.

Figure 1 illustrates the capacity drop of 11 Li-polymer batteries that have been cycled at a Cadex laboratory. The 1500mAh pouch cells for smartphones were first charged at a current of 1500mA (1C) to 4.20V/cell and allowed to saturate to 0.05C (75mA) as part of the full charge procedure. The batteries were then discharged at 1500mA to 3.0V/cell, and the cycle was repeated.