How to Prolong Lithium-based Batteries - Battery University

How to Prolong Lithium-based Batteries

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.

Figure 1: Capacity drop as part of

cycling

A pool of new 1500mAh Li-

ionbatteries for smartphones

istested on a Cadex C7400

battery analyzer. All 11 pouch

packs show a starting capacity of

8894 percent and decrease in

capacity to 7384 percent after

250 full discharge cycles (2010).

Courtesy of Cadex

Although a battery should deliver 100 percent capacity during the first year of service, it is common to see lower than specified capacities, and shelf life may have

contributed to this loss. In addition, manufacturers tend to overrate their batteries; knowing that very few customers would complain. In our test, the expected capacity

loss of Li-ion batteries was uniform over the 250 cycles and the batteries performed as expected.

Similar to a mechanical device that wears out faster with heavy use, so also does the depth of discharge (DoD) determine the cycle count. The shorter the discharge

(low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine;

there is no memory and the battery does not need periodic full discharge cycles to prolong life, other than to calibrate the fuel gauge on a smart battery once in a

while. Read more about Battery Calibration.

Table 2 compares the number of discharge/charge cycles Li-ion can deliver at various DoD levels before the battery capacity drops to 70 percent. The number of

discharge cycles depends on many conditions and includes charge voltage, temperature and load currents. Not all Li-ion systems behave the same.

Depth of discharge Discharge cyclesTable 2: Cycle life as a function of

depth of discharge

A partial discharge reduces stress and

prolongs battery life. Elevated temperature

and high currents also affect cycle life.

100% DoD

50% DoD

25% DoD

10% DoD

300 500

1,200 1,500

2,000 2,500

3,750 4,700

Lithium-ion suffers from stress when exposed to heat, so does keeping a cell at a high charge voltage. A battery dwelling above 30C (86F) is considered elevated

temperature and for most Li-ion, a voltage above 4.10V/cell is deemed as high voltage. Exposing the battery to high temperature and dwelling in a full state-of-charge

for an extended time can be more stressful than cycling. Table 3 demonstrates capacity loss as a function of temperature and SoC.

Temperature 40% charge 100% chargeTable 3: Estimated recoverable capacity

when storing Li-ion for one year

at various temperatures

Elevated temperature hastens capacity

loss. The capacity cannot be restored. Not

0C

25C

40C

98%

96%

85%

94%

80%

65%

http://batteryuniversity.com/learn/article/discharge_methodshttp://batteryuniversity.com/learn/article/battery_calibrationhttp://batteryuniversity.com/

60C 75% 60%

(after 3 months)

all Li-ion systems behave the same.

Most Li-ions are charged to 4.20V/cell and every reduction of 0.10V/cell is said to double cycle life. For example, a lithium-ion cell charged to 4.20V/cell typically

delivers 300500 cycles. If charged to only 4.10V/cell, the life can be prolonged to 6001,000 cycles; 4.00V/cell should deliver 1,2002,000 and 3.90V/cell 2,400

4,000 cycles. Table 4 summarizes these results. The values are estimate and depend on the type of li-ion-ion battery.

Charge level (V/cell) Discharge cyclesCapacity at full

charge Table 4: Discharge cycles and capacity

as a function of charge

Every 0.10V drop below 4.20V/cell doubles

the cycle; the retained capacity drops

accordingly. Raising the voltage above

4.20V/cell stresses the battery and

compromises safety.

[4.30]

4.20

4.10

4.00

3.92

[150 250]

300 500

600 1,000

1,200 2,000

2,400 4,000

~[110%]

100%

~90%

~80%

~75%

For safety reasons, lithium-ion cannot exceed 4.20V/cell. While a higher voltage would boost capacity, over-voltage shortens service life and compromises safety.

Figure 5 demonstrates cycle count as a function of charge voltage. At 4.35V, the cycle count is cut in half.

Figure 5: Effects on cycle life at

elevated charge voltages

Higher charge voltages boost

capacity but lowers cycle life and

compromises safety.

Source: Choi et al. (2002)

Chargers for cellular phones, laptops, tablets and digital cameras bring the Li-ion battery to 4.20V/cell. This allows maximum capacity, because the consumer wants

nothing less than optimal runtime. Industry, on the other hand, is more concerned about longevity and may choose lower voltage thresholds. Satellites and electric

vehicles are examples where longevity is more important than capacity.

Charging to 4.10V/cell the battery holds about 10 percent less capacity than going all the way to 4.20V. In terms of optimal longevity, a voltage limit of 3.92V/cell works

best but the capacity would only be about half compared to a 4.20V/cell charge (3.92V/cell is said to eliminate all voltage-related stresses).

Besides selecting the best-suited voltage thresholds for a given application, Li-ion should not remain at the high-voltage ceiling of 4.20V/cell for an extended time.

When fully charged, remove the battery and allow to voltage to revert to a more natural level like relaxing after exercise. Although a properly functioning Li-ion charger

will terminate charge when the battery is full, some chargers apply a topping charge if the battery terminal voltage drops to a given level. Read more about Charging

Lithium-ion.

What the user can do

The author of this essay does not depend on the manufacturers specifications alone but also listens to user comments. BatteryUniversity.comis an excellent

sounding board to connect with the public and learn about reality. This approach might be unscientific, but it is genuine. When the critical mass speaks, the

manufacturers listen. The voice of the multitude is in some ways stronger than laboratory tests performed in sheltered environments.

Tables 2, 3 and 4 look at cycle life as a function of discharge, temperature and charge level. A summary table should be added that also states the Optimal Battery

Energy Factor Over Life. While this would help in selecting the optimal battery, battery makers are hesitant to release such a specification freely, and for good reason.

A battery is in constant flux and capturing all of its data is exhaustive. A further criterion is price. Batteries can be built to perform better but this comes at a cost.

Lets look at real-life situations and examine what stresses lithium-ion batteries encounter. Most packs last three to five years. Environmental conditions, and not

cycling alone, are a key ingredient to longevity, and the worst situation is keeping a fully charged battery at elevated temperatures. This is the case when running a

laptop off the power grid. Under these conditions, a battery will typically last for about two years, whether cycled or not. The pack does not die suddenly but will give

lower runtimes with aging.

Even more stressful is leaving a battery in a hot car, especially if exposed to the sun. When not in use, store the battery in a cool place. For long-term storage,

manufacturers recommend a 40 percent charge. This allows for some self-discharge while still retaining sufficient charge to keep the protection circuit active. Finding

the ideal state-of-charge is not easy; this would require a discharge with appropriate cut-off. Do not worry too much about the state-of-charge; a cool and dry place is

more important than SoC. Read more about How to Store Batteries.

Batteries are also exposed to elevated temperature when charging on wireless chargers. The energy transfer from a charging mat to a portable device is 70 to 80

percent and the remaining 20 to 30 percent is lost mostly in heat that is transferred to the battery through the mat. We keep in mind that the mat will cool down once

the battery is fully charged. Read more about Charging Without Wires.

Avoid charging a battery faster than 1C; a more moderate charge rate of 0.7C is preferred. Manufacturers of electric powertrains are concerned about super-fast

charging of 20 minutes and less. Similarly, harsh discharges should be avoided as also this also adds to battery stress. Read more about Charging Lithium-ion and

Ultra-fast Chargers.

Commercial chargers do not allow changing the charge voltage limit. Adding this feature would have advantages, especially for laptops as a means to prolong battery

life. When running on extended AC mode, the user could select the long life mode and the battery would charge to 4.00V/cell for a standby capacity of about 70

percent. Before traveling, the user would apply the full charge mode to bring the charge to 100%. Some laptop manufacturers may offer this feature but often only

computer geeks discover them.

http://batteryuniversity.com/learn/article/charging_lithium_ion_batterieshttp://batteryuniversity.com/learn/article/how_to_store_batterieshttp://batteryuniversity.com/learn/article/charging_without_wireshttp://batteryuniversity.com/learn/article/charging_lithium_ion_batterieshttp://batteryuniversity.com/learn/article/ultra_fast_chargers

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Another way to extend battery life is to remove the pack from the laptop when running off the power grid. The Consumer Product Safety Commissionadvises to do this

out of concern for overheating and causing a fire. Removing the battery has the disadvantage of losing unsaved work if a power failure occurs. Heat buildup is also a

concern when operating a laptop in bed or on a pillow, as this may restrict airflow. Placing a ruler or other object under the laptop will improve air circulation and keep

the device cooler.

Should I disconnect my laptop from the power grid when not in use? many ask. Under normal circumstances this should not be necessary because once the

lithium-ion battery is full the charger discontinues charge and only engages when the battery voltage drops. Most users do not remove the AC power and I like to

believe that this practice is safe.

Everyone wants to keep the battery as long as possible, but a battery must often operate in environments that are not conducive to optimal service life. Furthermore,

the life of a battery may be cut short by an unexpected failure, and in this respect the battery shares human volatility.

To get a better understanding of what causes irreversible capacity loss in Li-ion batteries, several research laboratories* are performing forensic tests. Scientists

dissected failed batteries to find suspected problem areas on the electrodes. Examining an unrolled 1.5-meter-long strip (5 feet) of metal tape coated with oxide

reveals that the finely structured nanomaterials have coarsened. Further studies revealed that the lithium ions responsible to shuttle electric charge between the

electrodes had diminished on the cathode and had permanently settled on the anode. This results in the cathode having a lower lithium concentration than a new

cell, a phenomenon that is irreversible. Knowing the reason for such capacity loss might enable battery manufacturers to prolong battery life in the future.

* Research is performed by the Center for Automotive Research at the Ohio State University in collaboration with Oak Ridge National Laboratory and the National

Institute of Standards Technology.

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Comments

On October 21, 2010 at 10:38am

John Vanderkooy wrote:

I am grateful to Cadex Electronics for the w hole w ebsite explaining batteries. It is really helpful to restore useful units, assess questionable ones, and the explanations are at a

university level. Thanks.

On October 26, 2010 at 5:29pm

pamela knowler wrote:

How long do I charge a new laptop battery before use? The battery arrived partially charged and information suggests I charge it fully before using. I cant seem to f ind any information

about how long to charge it...its a lithium ion 9 hour (lenovo) laptop battery.

thanks


Dennis Lackey wrote:

10-28-10, I sell cell phones and other devices that use lithium batteries and I have been misinforming my customers inregardes to charging requirements of their batteries. ireally found the

information reall useful. Thanks, Dennis


Taurug Baca wrote:

What is 1C? What is a C?

On November 6, 2010 at 2:28am

Fred B wrote:

Taurug Baca w rote: What is 1C? What is a C?

To quote http://en.w ikipedia.org/w iki/Battery_charger:

Charge rate is often denoted as C or C-rate and signif ies a charge or discharge rate equal to the capacity of a battery in one hour. For a 1.6Ah battery, C = 1.6A. A charge rate of C/2 =

0.8A w ould need tw o hours ... to fully charge the battery from an empty state, if supported by the battery. This also assumes that the battery is 100% eff icient at absorbing the charge.

On November 13, 2010 at 3:38pm

James wrote:

What about overcharging? What are the effects of leaving a Lithium-ion battery charging w hen at full capacity?


James wrote:

Also, is there an ideal range to charge/discharge the battery in e.g. 40%-70%, ensuring a partial discharge?


3.7kLikeLike

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Carlos Jordan wrote:

I really appreciate your technical info on Lithium-ion batteries. I recently purchased a w onderful Panasonic Camcorder, w hich uses such a battery, and your advice not to fully discarge,

before re-charging is so very helpful, as I thought according to the manual, it w as necessary to discharge fully.

As James asked above, w hat is the ideal partial discharge, before charging again?

Thanking you kindly for your help.


nygus wrote:

Sadly, macbooks (and other laptops) run much slow er on f ixed pow er (even 4x slow er), w hen battery is removed so battery dies very quickly. I think they use battery as capacitor to

support short demands of higher pow er.


David wrote:

If it is better to have the battery charged to 40% and then stored w hile on main pow er, w hy do the laptop manufacturers not program the BIOS to have an option to charge to 40% and

stop? I am alw ays on f ixed pow er, the problem w ith removing the battery at 40% is that I w ould be vulnerable to pow er outages. With the battery still inside the laptop charged to 40% I

w ould be saving my battery, saving pow er and saving my data in the event of a main-pow er failure. Does anyone know if there is a softw are out there w hich could charge to 40% and

stop? If so, please let me know .


Patrick Woo wrote:

How frequent should I apply a full discharge to recalibrate the fuel guage?

Every 30 charges sound very frequent to me if your laptop alternate betw een battery pow er and f ixed pow er many times a days.


Andy wrote:

Frequent full discharges should be avoided w hen possible

and

A deliberate full discharge and recharge every 30 charges corrects this problem

How are these recommendations compatible? It is really safe to *completely* discharge the battery? Wouldnt it die after a single *full* discharge?

On December 2, 2010 at 7:22am

Mehper C. Palavuzlar wrote:

@David:

Follow this question on SuperUser.com:

Softw are to hold battery at 50% charge level

http://superuser.com/questions/217480/softw are-to-hold-battery-at-50-charge-level

On December 7, 2010 at 9:19pm

Dave wrote:

Does freezing cause dammage to the batery? Or does using the battery in a cold or frozen state cause the dammage? Can a battery be frozen allow ed to thaw and be f ine?


Andrew wrote:

@David

You do not w ant to leave your battery in your laptop even if w ould remain at 40% because your laptop generates quite a bit of heat from use w hich is harmful to the batteries. The lithium

batteries should be stored at 40% AND in a cool place.


Phil wrote:

This is one of the articles that I w as reading about caring for your laptop batteries.


Carol Nemetz wrote:

I removed battery for a number of hours. Whn I replaced it the battery icon read"plugged in, not charging I have had this problem w ith not chargeing a number of times. After 4 attempts,

Gatew ay repaired it. The last time they replaced the motherboard and installed a new battery.All w as w ell until I removed he battery and replaced it


Fede wrote:

Most of the time I use my laptop at w ork. I use it w ithout the battery and I keep it at 40%.

What I noticed is that if I put the battery again after a few days the charge had low ered to 30% for example.

So, If I the ideal storage is at 40% but after a few days the charge drops to 30%, how can you keep it stored at 40%?


Daniel wrote:

Thank you for this infomation, people complain w ith the performance of their laptops, just maintain and look after your bleeming laptop!

Thanks to Battery University for this infomation


Jaime Blanco wrote:

I have not seen that this question is answ ered so I w ill add my question to the queue. Is there an ideal rate of w hen to charge the battery ? eg. 40% ... or 70% ?? BTW With this

article I have f inally understand how to use my battery thx!!! I w as living a lie.. and in the past I knew battery industry had evolved this years..

On January 1, 2011 at 8:32am

Gcat122 wrote:

The Verizon sales clerk insisted that I not leave my droid 2 on the charger for more than 4 hours or the battery w ould be damaged. I have trouble believing a new smartphone w ould be

dumb enough to kill batteries. Is he w rong or is the manufacturer trying to sell more batteries?


Ike wrote:

Gcat122, properly made Li-Ions should have built-in protection that prevents problems caused by overcharge. How ever, you may have heard about massive battery recalls in the recent

years due to quality problems causing overheating or even explosions - so his suggestion may have been related just in case caution.

Normally, a quality charger w ill notice w hen the battery is full and cease attempts to overload it. But itbeen proven that all chargers arent that smart, especially generic brand ones that

may apply charging methods unsuitable for Li-Ion type.

On January 6, 2011 at 6:22pm

Niall wrote:

w ould carging my battery w hilst using it do any damage to it? this appears to be the only information i cannot f ind on lithium ion battaries


Mike wrote:

I just purchased a 20v professional cordless drill/driver (Craftsman brand) from Sears at 60% off the original price. This item w as marked clearance. Ive been congratulating myself on

a great f ind until I read this article. I immediately checked the date on the tw o lithium-ion batteries enclosed and found it to be 10 2006. I think I know now w hy they have been reduced to

clear. Ive charged up the batteries and they seem fine, but I havent used the drill yet so dont know w hat performance and battery life to expect. I have to assume that these items have

been sitting in a w arehouse or store uncharged for over four years.

What remaining life should I expect from a four-year old battery that has never been charged? Should I consider returning the drill?


Tad wrote:

@Mike - if the drill carries the standard Craftsman forever w arranty, you can alw ays return the drill if the batteries prove to be unsatisfactory.

Lately my Blackberry 9700 has taken to pow ering itself off suddenly w hen the battery gets dow n around 1 bar, before it even reaches the yellow or red part of the gauge. This may

be due to my recently acquired habit of charging it every night.

Ill let it run dow n a few times and see if that makes a difference.


Michael wrote:

Great info!

One comment - a couple of your graphs are the w rong w ay around - the convention is to have the independent variable on the x-axis. So, in the last graph, you should be reading off the

number of cycles on the y-axis, against each charge/discharge rate on the x-axis. (The number of cycles is *dependent* on the charge/discharge rate).


dewey hodo wrote:

Does the above care, use and charging instruction apply equally to EV lithium batteries?

What special care must be given for Li batteries hundreds of times larger and more pow erful than laptops?


John wrote:

Hi, great article, but I have one question. What about Li-Polymer batteries, does all this apply to them also or are there some signif icant differences?


Victor wrote:

My battery cant backup anymore, and I only get to have Pow er for 6hours a day. and Im a Programmer. Getting another is just too expensive so how can I make it w ork again! Im using a

UPS for a LAPTOP.


Cobalt wrote:

Keep the lithium-ion battery cool. Avoid a hot car. For prolonged storage, keep the battery at a 40% charge level.

So i need charge battery every time w hen battery indicator is at 60%???


Ashley wrote:

This is an aw esome article, it explains everything in detail and is backed up by evidence, making all the information very credible.

How ever, I still do not grasp the definition of discharge. Does it mean letting the battery run out; let it completely die?

My phone has been having battery issues I hope I can f ix it!


Hilda Smith wrote:

Thank you for this very helpful information.


Royce wrote:

I stored my lit. battery from my laptop to increase battery life. After six months I reinstalled the battery and it w ill not charge. Was storing it six months too long?


Alex wrote:

It depends on the state of charge w hen you stopped using it. If it is almost completely discharged 6 month might be too long.


Alex wrote:

You should try leaving the battery 1 - 2 days plugged in, it might recover


Alex wrote:

If it doesnt seem to have charged after 1 - 2 days, it has to be taken apart and the cells have to be charged directly before the protection circuits. A pow er supply that can provide

constant current is needed, for ex a lab pow er supply. The voltage should be set to the voltage w ritten on the battery and the max current should be set to 5% of total capacity. Obviously

the polarity has to be connected correctly and the charging process should be left alone for aw hile until the constant current disappears. After that the battery should be placed in the

laptop and it should charge normally.


Alex wrote:

And, theres another thing. if w hen you try to pow er the laptop w ith the bad battery the lights f lash as if it tells you that the battery is bad that it might never charge and it also might not

solve the problem charging the cells before the protection circuits inside. It is best to try something else before you charge the cells separately. after taking the battery apart disconnect all

w ires from the cells that go to the protection circuits. it is easier to desolder them from w here they are near the cells rather than from th pcb, but this might not be the case for all the

batteries. After desoldering all w ires leave it like that for 10 seconds than resolder the w ires back to w here they w ere. you should connect the battery into the laptop and try to charge

it. In a similar situation it w orked for me. Through this method you cut the pow er from the protection circuits and it resets some parameters related to the battery monitoring


Mescoda wrote:

I have translated this useful article into Chinese on my blog

If anyone get interest in it,you can visit

http://mescoda.com/2011/01/how -to-prolong-lithium-based-batteries/


ptah wrote:

Interesting to note that some laptop computers have the battery pack protruding from the main case. That may be intended to reduce exposure to heat released by other components.


DickL wrote:

I w ould like to know w hat is different, if anything, about charging and discharging Lithium Iron Phosphate (LiFePO4) batteries - relatively new chemistry in the Lithium family of batteries.

Folks at Batteryspace.com claim much increased number of cycles (>2000) if managed conservatively. Any observations or recommendations?

- DickL

On February 4, 2011 at 3:04pm

Ty wrote:

Excellent information on Li-Ion laptop batteries. Approximately 500 charge and discharge cycles is pretty accurate. How ever, some companies claim 1000 or more. It all depends on the

quality and grade of the battery cells. Cheap battery cells w ill not last very long. Whereas a w ell build battery w ith high quality cells should have a normal lifespan, given its not put in

abusive environments.

-Ty

w w w .ebatts.com

On February 7, 2011 at 9:13am

suman wrote:

w at about over charging?

do w e hav problem in doping it


jean wrote:

w hat does discharge mean?


steve wrote:

Im w ondering w hat the effect of freezing is on the lithium ion batteries in my Makita cordless driver/drill. Working in the w inter in Iow a, freezing temperatures are common at w orksites.

Will frequent freezing reduce the total number of charge/discharge cycles Ill get out of my batteries over the life of the tool?


Prem Dissanayake wrote:

Its great place to study about battery as w ell as other related accessories.Good luck!


Pier Francis wrote:

Excellent info on batteries, thanks to Battery University


Andrew wrote:

I also w anted to express my gratitude on the information given about lithium based batteries. Thank you!


Brandon wrote:

We have updated this article as of today February 25, 2011.


Rob Smith wrote:

I tried to fgure out how to handle longevity and the best solution so far is by Sony VAIO laptops. During normal use in off ice I put charge limit to 40% and batter never goes above that, if I

need to travel I simply increase it to 80% or 100%.

Capacity of battery remained constant for more than 2 years now , w hat might be due to such soft charging, but also due to quality of Sony batteries.

Dell Studio XPS has excellent utility w hich simply turned charging off w henever user w ishes.

So I keep charge level somew here around 50% and w henever I need laptop simply turncharging on.

IMO it should be standard on all laptops.

On March 1, 2011 at 11:13am

mike wrote:

Question: I w as told to leave the computer on at all times, just shut the lid. This w ill add to the life of the battery. Comments

On March 12, 2011 at 11:33am

genesis wrote:

people,please..do not take everything you read on internet as a must. w hat this ....article acctually tells you is: 1) it is not recomended to keep your battery plugged in w hen fully

charged for a long time periods.2)it is not neccessary to alw ays fully discharge the LI battery(you can charge it anytime to any%). 3)do not keep/operate your battery in an ow en.4) if you

plan not to use your battery for a long time, it is better to keep it half charged.

thats about it - everything else is just a .... masochism.

On March 12, 2011 at 12:00pm

gendersis wrote:

thanks genesis, i w ill do as you said, hopefully my battery w ill survive another year :D

On March 20, 2011 at 11:07am

Kevin wrote:

Aw some sightI have an Evo Shift and my battery gets up too 47 degrees w hile using it and sometimes noy slow ly? Sprint said that its ok? Please HELP!!!!!!

On March 23, 2011 at 3:44pm

SLy wrote:

****Tad w rote:

@Mike - if the drill carries the standard Craftsman forever w arranty, you can alw ays return the drill if the batteries prove to be unsatisfactory.****

COMPLETELY WRONG!!!

Craftman Hand Tools are lifetime. Cordless drills and other similar items are NOT lifetime.

The battery you bought has a 90 day w arranty. Same as the charger. The tool has a year w arranty.


derp wrote:

Most of you are absolutely retarded, especially genesis. This article is not telling you to avoid putting your battery in an oven (or ow en as you so aptly put), but to instead avoid using the

laptop w hile on the pow er grid w ith the battery fully charged.

For all you derps out there (most of you, judging by your comments), this means that you should not keep the battery in the laptop w hile it is plugged in and you are using it. Laptops

generate heat (hurr durr) and since the battery is in the laptop (again, hurr durr), it is exposed to the heat, AND is kept constantly at full charge w hile plugged in. So, no, genesis, one

doesnt require an oven to expose your battery to heat (derp). Laptop internals regularly get to 60-70 degrees Celsius, w ell above the stated ideal temperature for batteries.

And I CANT believe one of you actually stored a laptop battery for SIX MONTHS to GAIN battery life. What a tard. Never using a battery w ill zap the pow er quickly.

Heres another thing. I left a laptop mostly plugged in for a year. It had VERY few discharges. Yet the battery lasted for only a 1/2 hour or so. So you tards be the judge as to w hether or

not keeping it plugged in w ith the battery installed leads to excess w ear.

As for actually using the battery (w hen not plugged in), just use it. Avoid full discharges and dont keep it in a hot area.

And for all you idiots w anting to magically make your depleted batteries w ork again: you are, as I mentioned, idiots. Everything has a lifespan. If youve had your battery for a w hile and

used it often, then guess w hat? Its old and used and you have to buy another one! YAY! HURR DURR!

And some derp mentioned people complaining about laptop performance: WTF are you talking about? Someone said that laptops function slow er w ithout the battery w hile on pow er, but

thats the only complaint I heard. Youre just a retard.

And someone here actually doesnt grasp the concept of a discharge. Are you serious? Look up the w ord. Good Lord. Mega tards.

Anyw ay, thanks everybody for decreasing my hope in humanity even more than previously. The internet does that quite often. Bye, retards.


James wrote:

derp has a point.. and summarizes the article w ell

..but he came over as a an obnoxious braggart.

On March 27, 2011 at 10:02pm

Sagar wrote:

Great articleThanks for sharing


wezz wrote:

ive just bought a new cordless lithium drill/driver for DIY use only have i made a costly mistake? thanks w ezz


Paul wrote:

I have been looking at this and I think the data is a bit mis leading. Its not the number of re-charges that is important, but the total hours before the battery cannot get to above 70%.

I have been a geek and modelled this. If you take an average battery w ith a life of 600hrs in standby (the actual number dont matter here), then the total hours you get for the 100%DoD is

actually more than the 10%DoD. Yes, you get more recharges, but less total hours of use. From the table in the article, the 50% DoD gives you the most number of hours out of the battery

before it cannot get above 70%.

Its quality not quantity!

p.s. I havent read all the comments so I apologise if I am repeating w hat has been said!

On April 4, 2011 at 8:20am

Rich S. wrote:

The question is often asked: Should I disconnect my laptop from the pow er grid w hen not in use? Under normal circumstances this should not be necessary because once the lithium-ion

battery is full, a correctly functioning charger w ill discontinue the charge and w ill only engage w hen the battery voltage drops to a low level. Does this same thing apply to the phone

batteries?


Dave wrote:

Obviously, as derp left his ow n laptop mostly plugged in for a year, he is, by his ow n definition, a retard. What a jerk.


David wrote:

Table 2 states that for a full 100% discharge and full charge that the battery w ould last roughly 500 cycles, w hile one that has a 10% discharge and then charging back up to 100% w ould

last roughly 4,700 cycles. I hope I understand that table correctly, if not please help me understand it better.

My question is that given that I w ould follow the 10% discharge cycle w ould that not cause the battery to fail sooner since discharging 10% and then charging to 100% 4,700 times

w ould roughly equate to 470 100% discharges? Im sure I may be misunderstanding something, but I dont see how the numbers add up.


Paul wrote:

The key isnt the number of re-charges, it is the total hours you get out of the battery. So you are, approximately, right. Look at my comments above.

More re-charges does not necessarily mean more battery life. Just means more re-charges

Paul


David wrote:

Thank you Paul! That helped out greatly. I w ill include my f indings doing similar calculations here:

Total capacity: 100 mAh

Dod Cycles Total Hours of use Formula (capacity * Dod) * Cycles

100% 500 50,000 (100 * 1.00) * 500

50% 1,500 75,000 (100 * 0.50) * 1,500

25% 2,500 62,500 (100 * 0.25) * 2,500

10% 4,700 47,000 (100 * 0.10) * 4,700

Please let me know if I used anything incorrectly.


Paul wrote:

It is close, but it does depend w hat they mean by 10% DoD

If you look at the graph (f igure 1), it show s that each time you charge, the full level on the battery is a bit less each time. The failure is w hen it can only get to 70%. So lets say you

charge 2000 times, the batt may only charge to 80%, say. Then 10% DoD in this case w ill be (in your example) 10% of 80mAh. If they meant 10%DoD of the orginal batt capacity in each

charge, then you are right but I doubt it. I say that because if that is w hat they meant, then they could not have done a 100% DoD case (how can you discharge 100mAh w hen the batt is

only at 80mAh?)

So in your cals, w here you have (100*0.10)*4,700 the 100 needs to be a decreasing value for each charge e.g. (100*0.1) + (99.9*0.1) + (99.5*0.1) or similar

Does that make sense?

Paul


Ed Vim wrote:

Great article, thanks for w riting this up.

Regarding derps comments, interesting but its value greatly diminished by immaturity.


David wrote:

@Paul

Yes that makes sense. I w ould update the calculations to account for that but I have already had enough fun for the day.

Thank you for the response.

On April 8, 2011 at 6:01pm

Patrick B wrote:

I keep my laptop plugged in all the time at home to do w ork on. According to this article, it seems that by doing this, I am w earing out my battery prematurely. I take it the right thing to do

w ould be to let it partially discharge, then take it out of the unit until I need to use it on battery pow er. Am I right?


thomas 09789989648 wrote:

hi i am a laptop service enginear how to check battery ok or bad . and how to create one lithiyam ion battrey on charging pls tell me


GenericM wrote:

I hope my laptop never needs servicing even more now .

On April 10, 2011 at 8:49pm

elf- wrote:

I just bought a new battery for my Huaw ei Ascend cell phone I have let the battery drain completly out then gave it a full charge then let it die out and gave it a complete charge again. From

the reading above, If I w ant too prolong the battery life I should let it drain dow n to 50-60% battery life then put it on the charger? Or do I keep on letting it drain dow n to 10-15 % then put it

on the charger for 4 hours or until 100% charged? Please respond back thanks!


Paul wrote:

Based on the data they show in the paper, the 50% DoD seems to give you the longest batt life.

But I am not an expert, I am just analysing their data.


PAUL J. wrote:

Funny, if you paid $200 to read David Lindens Handbook of Batteries 3rd Edition it w ill tell you that lithium ion batteries have a good shelf life. Primary lithium does, but not Li-ion. This is

straight from Lindens $200 book:

TABLE 35.1 Advantages and Disadvantages of Li-ion Batteries

Advantages Disadvantages

Sealed cells; no maintenance required Moderate initial cost

Long cycle life Degrades at high temperature

Broad temperature range of operation Need for protective circuitry

Long shelf life

Low self-discharge rate

Rapid charge capability

High rate and high pow er discharge capability

High coulombic and energy eff iciency

High specif ic energy and energy density

No memory effect


PAUL J. wrote:

Elf, it does not matter w ith Li-ion. Just charge it w henever you get a chance, but just so you know Li-ion is happiest around 40% state of charge.

On May 2, 2011 at 11:42pm

Mike wrote:

The question most raised is life. Our batteries utilize precision GPS on job sites. The manufacturer of the units is very attentive to detail as far as expansion w ith charging. They utilize a

gore valve to help w ith the hear w hen the batteries and components expand. How ever, the replacement batteries w e receive, w hich i believe are quality last almost half the time as the

original manufacturers batteries. Do you believe this to be a coincidence or quality factor.

On May 2, 2011 at 11:46pm

Mike wrote:

The question most raised is life. Our batteries utilize precision GPS on job sites. The manufacturer of the units are very attentive to detail as far as expansion w ith charging. They utilize

a gore valve to help w ith the heat w hen the batteries and components expand. How ever, the replacement batteries w e receive, w hich i believe are quality, last almost half the time as the

original manufacturers batteries. Do you believe this to be a coincidence or quality factor.

On May 3, 2011 at 6:17am

PAUL J. wrote:

There seems to be a lot of controversy on the subject of lithium-ion batteries and w hat you should do w ith them w hen you f irst receive them. The experts w ill tell you that there is no

conditioning needed w ith Li-Ion, how ever I have seen f irst hand experience w hich begs to differ.

I have seen proof time and time again that Li-Ion DOES benefit greatly from conditioning the battery by letting it discharge fully (until the device shuts itself dow n) and charging it 8-12

hours (repeat process) for the f irst 3-5 days.

That could solve your problem, or you might just be getting old batteries.

Next time you receive a new battery, try this method, I think you w ill be surprised.

On May 4, 2011 at 8:14am

Rob wrote:

@ Paul J

That could also be just dow n to the fact that this sort of cycling is used to calibrate the battery mater in some equipment - Apple Macs spring to mind here. So repeating this until your

battery is in peak form (usually 3 or 4 cycles) w ill keep updating the calibration values and hence give you the most accurate reading. This in turn w ill give the longest time before the

softw are of the device thinks the battery is nearly f lat and shuts dow n to protect your information.

Anyw ay, thanks for the thread. Its amazing the amount of FUD that there is out there, not helped by the fact that most manufacturers are particularly vague w ith regards to their battery

care and handling instructions. They could all do w ith having an article similar to this, but specif ic to their particular battery, charger circuit and typical usage patterns, in their manual.

On May 8, 2011 at 1:29pm

danceswithbongs wrote:

Thanks for an informative article. Wasnt it nice of derp to drop by, making use all feel better about ourselves. Alw ays good to notice that mans inhumanity to man is hard w ired. I w ould

imagine derp could learn a bit from someone w ho is retarded, like how to treat others.

Again, great article, and f irst free thing Ive ever heard of from a university.

Can people still major in 9 volts?

Appreciate you droppin know ledge like Galileo dropped the orange!(see The Beastie Boys)

From the law off ices of dancesw ithbongs, esq.

On June 2, 2011 at 3:25pm

INSAAN KHAN wrote:

CAN SOMEONE HELP ME?

I BOUGHT A NEW ASUS Eee PC 1008P and i am facing problem w ith my battry charging

my battery charges w ell w hen netbook pow er is off but w hen i sw itch the netbook on the battery light keeps on blinking and w indow s 7 tray show s at my battery is intermittently

charging and disconnecting.(that is the reason w hy my battery light is blinking..w hich w ould remain static if it is charging normally)

please helpor should i be needing to go the ASUS tech help?

thanks

On June 8, 2011 at 7:34am

Charge Me wrote:

Sooo, w hy is it of the dozen laptops Ive ow ned over the last ten years, that they still had less than 5% w ear after one year and less than 15% w ear after tw o years and kept them at

100% and had maybe 10-20 full discharges a year?

On June 14, 2011 at 7:47am

Marilyn wrote:

A few years ago a physicist friend explained to me that it doesnt matter how far you discharge the battery but once its on the charger it should be left on until the battery is fully charged.

My boyfriend (a chemist/scientist) says this is complete untrue w ith the current battery technology. He tends to charge his phone in short stints w here I tend to never attach to the

charger unless I can leave it long enough to fully charge. Any thoughts? (We both have the Samsung Galaxy S w hich is a great phone but a huge energy suck. I must recharge once a

day w hich I do at then end of the day until the morning.)

On June 15, 2011 at 6:49am

Paul J. wrote:

Your boyfriend is correct. Lithium Ion technology can accept a topping charge at any time and doe not require a full charge. I also have a Galaxy S and I charge it w henever I get a

chance. You should prime the battery the f irst few days though by draining it completely and charging completely. This w ill also help calibrate your phones battery meter to the new

battery.

On June 22, 2011 at 10:26am

Crusty wrote:

Derp is certainly a character. OK, hes douche. There, I said it. Anyone have any luck w ith freezing dead batteries and bringing them back to life? Some say it w orksIm skeptical. Im

trying it now w ith an HP dv7 battery (OEM HP from 9/2009) I guess it cant hurt. Besides, this monster 7lb laptop is lighter w ithout the battery. Works f ine on straight AC.

On June 25, 2011 at 2:37pm

Alan Kanarbik wrote:

I appreciate the resourcefulness of the information you have provided here.

Another question has come to my mind regarding saving pow er on Li-ion batteries. Will it make no difference to plug the battery in and out w ith the laptop running on AC pow er or is

battery life saved by turning the computer off f irst for the sw itch betw een pow er sources?

On June 25, 2011 at 10:42pm

Crusty wrote:

My guess is if you are going to have your laptop plugged in most of the time, as in a large, say 17 desktop replacement type, it w ould be best to just remove the battery altogether. Such is

the case w ith my HP DV7 laptop w ith its beautiful 17.3 screen. Lugging around a nearly 8lb laptop (w ith battery installed) for any great distance w ill make a man pine for something much

smaller (and lighter!) Seriously, if youre leaving it at home or off ice most of the time, w hats the point?

Oh, and the freeze your dead battery thing I tried from another site? Well, unless it says Lazarus somew here on the label next to the P/N, this appears to be bunk. It w as w orth a try, I

guess. All you need is a dead battery and a freezer bag. . . . .

On June 30, 2011 at 9:57am

Niels-Erik Jensen wrote:

How many kWh do you have to get from the pow er supplier to get 100 kWh into the battery.

The heating up of the battery show s you have to tap (a lot, maybe) more kWh from the pow er supplier than the energy that is charged into the battery.

Same question for discharging a battery w hich also gets hot during de-charging.

On July 14, 2011 at 1:47pm

Colin Macdonald wrote:

I am thinking of buying an electric bike, but I go aw ay to Africa during the British w inter, so the battery w ould be stored unattended for six months each year. Is this going to be a

problem? Have you any advice?

On July 14, 2011 at 7:51pm

Marilyn wrote:

Thanks Paul, Ive started taking both of your advice and charging the phone w henever I have a charger available. I still f ind myself draining the battery before I f ind a charger, today it w as

too many birds and not enough pigs, but Im getting better. Phone is w ell primed based on my previous charging habits.

On July 15, 2011 at 7:10am

Gerge lopaz wrote:

Too much information, not specif ic, hard to f ind information that is relevent.

On July 18, 2011 at 7:58am

Walt Borntrager wrote:

I have found just the opposite of this data in multiple Li-ion applications. In both notebook computers and cell phones, Ive found that if I never recharge the battery unless it is fully

discharged, and then alw ays fully recharge it, I get years of full capacity. My f irst cell phone w ould run 13 to 14 days continuously per charge for nearly 10 years using this rule. (Then

communication protocols changed from analog to digital. )

I had a notebook computer charging module w ith an intermittent connection at the output, charging a minute or so, then disconnecting and allow ing the computer to discharge a minute or

so, then charging a little In less than 1 day, the battery had no capacity - w ould not hold enough charge to hold up the computer for 10 seconds. The previous day it w ould pow er it for

nearly 2 hours. The battery did not undergo any shock - the computer w as sitting on a table.

Ive found the same for Ni-Cad (obviously) and also NiMH.

My personal experience in using rechargeable batteries for the last 20 years consistently agrees w ith this rule.

On July 23, 2011 at 1:27am

Jeff Simon wrote:

Maybe I am the only one missing one aspect of the number of cycles verses depth of discharge: if you only get 500 cycles w ith 100% discharge, as compared to 4700 cycles w ith 10%

discharge, those cycles are not equivalent.

That is, the 100% discharge got 10 times the pow er ouput as compared to the 10% depth. If assuming useful w ork w as done in each depth, then in fact getting 500 cycles actually gets a

bit more w ork than 4700 cycles of only 10% the depth.

This seems to me to say that the depth of discharge is much less important than you w ould initially think from just looking at the number of cycles alone, as the amount of output is actually

slightly more under the deep cycle, but for practical purposes is close to equivalent.

That is, unless I am missing something that everybody else is seeing.

On July 25, 2011 at 3:53am

Jim H wrote:

I have a new netbook and w ant to preserve the Li Ion battery as long as possible. I have no occasion to need to use the netbook on the battery, but I may someday. Ive had the netbook

about a month and have not installed the battery. Is this a good strategy? Should I charge the battery about half w ay and put it in the fridge sealed to prevent moisture incursion

On July 25, 2011 at 6:19am

Paul J. wrote:

My suggestion to you w ould be to read the article instead of just the comments. It seems like only a few people actually took the time to read it, and everyone else w ants answ ers w ithout

doing the reading. I have read the w hole book Batteries in a Portable World and I w ould recommend it to anyone w ho w ould like to have a better understanding of batteries and the

characteristics of each chemistry.

On July 25, 2011 at 6:22am

Paul J. wrote:

Jeff, I think it is just stated to be equivalent for practical purposes because it is close enough.

On July 25, 2011 at 8:21am

Jeff Simon wrote:

Paul, yes w hat I am saying is that they are practically equivalent. But the article seems to imply that very small cycles is far better.

On July 26, 2011 at 6:35pm

Walt Borntrager wrote:

Paul, I read the article and am saying that my 20+ years of experience w ith rechargeable batteries disagrees w ith one primary implication: The article implies that many partial cycles w ill

allow the battery to keep full capacity longer. The memory effect that plagued NiCad chemistry and supposedly is not present in Li-Ion, is the effect that, if the battery is only partially

discharged, then recharged, it w ill soon only have the capacity to w hich it is used, i.e., if you only discharge it 10% and then recharge it each time, after a number of cycles, the total mAH

available w ill only be about 10% of its original capacity. My experience has found this true of NiCad, NiMH, and Li-Ion, although Li-Ion is the most forgiving. As I stated before, a faulty

charger connection caused very small cycles on my last Li-Ion and it destroyed the capacity in days. I w ould certainly not recommend discharging any of these chemistries small amounts

betw een recharges. Ive seen this habit destroy capacity very prematurely numerous times.

Most of todays notebook computers have a hysteresis built into the charge cycle such that, if you fully charge it, no charging w ill occur until you have intentionally discharged it to some

extent. This allow s you to keep it plugged in for periods of time w ithout excessive short charge cycles. Some also have the option to turn the charger off until it is really necessary at a

low remaining charge. This is a clue that notebook computer manufacturers agree w ith me on this aspect.

On July 27, 2011 at 7:40am

Paul J. wrote:

Walt, I agree w ith you that Li-Ion doesnt alw ays behave exactly as indicated in the article. My comment about reading the article w as not pointed at you or others w ho are here to

discuss f indings and experiences. It w as for the people w ho just come here for free answ ers w ithout putting forth any effort to actually learn w hat the article is teaching.

That said, bear in mind w hen you read this article that it w as published in 2001. Lithium-Ion technology has advanced and is better understood now than it w as in 2001.

Isidor Buchmann has released a third edition just a couple months ago that I cant w ait to get my hands on.

On July 28, 2011 at 3:10am

Sandeep wrote:

Is it really a good practice to keep the charger on for my laptop even after my battery has reached 100%(fully charged)? If not does this have an implication on the life of the battery and

by how much? Is energy w asted in the process becuase the charger tries to keep pumping into an already full battery and if so w hat is the loss like?

On July 28, 2011 at 5:42pm

Walter Borntrager wrote:

Sorry Paul - didnt notice that this w as an old study. Good point - read and think through the article before asking a question that w as already answ ered.

I tend to spout off a bit over this subject because of all the hype that Li-Ion has beat the memory effect syndrome. I havent found a solid chemistry yet that has

(By solid, I mean this primarily excludes lead acid, w hich thrives on a continuous full charge, w ithin limits, and can be destroyed by a full discharge.)

Thanks for the comments

Walt

On August 1, 2011 at 3:16am

NeilP wrote:

Jim H,

If you have still not plugged your batteryinto the laptop, then DONT.

I have heard, but cant confirm, that the batteries, factory fresh, are chemically stabilised, somehow . The f irst charge cycle or tw o disapates this stabilisation, hence the need to cycle the

battery a few times to get full capacity

Colin, Ref your E bike battery. That totally depends onthe chemistry of the pack, It could be Sealed Lead Acid, or a LiFePO4 or?? Check out the Endless Sphere E bike forum for an

answ er,once you know battery chemistry


Retxirb wrote:

First let me thank you for this great article and this w ebsite, very informative. I recently bought new netbook and Ive been charging the battery for around 40% to 80%. I charge it up 40%

w hen I w ont be using the battery for a long period of time. I pull out the battery w henever I have access to pow er outlet.

Charging the battery w hile the computer is running may cause the battery serious stress because of heat. But I occasionally charge my netbook around 7pm w hen the temperature is cool

so I can w atch the netbook w hen its reached 80%.

I know that everything even computer battery has an end. If I reach that point, I w ould dissect the battery, ebay some Li-Ion and then solder it to place. That w ould save me a lot of bucks.


NeilP wrote:

Jim H,

If you have still not plugged your batteryinto the laptop, then DONT.

I have heard, but cant confirm, that the batteries, factory fresh, are chemically stabilised, somehow . The f irst charge cycle or tw o disapates this stabilisation, hence the need to cycle the

battery a few times to get full capacity

Colin, Ref your E bike battery. That totally depends onthe chemistry of the pack, It could be Sealed Lead Acid, or a LiFePO4 or?? Check out the Endless Sphere E bike forum for an

answ er,once you know battery chemistry


Fabrice wrote:

Paul, note:


Isidor w rote:

We have updated this article as of today February 25, 2011.

Still, I w ish he w ould address the point raised about battery utility (i.e., total pow er delivered) vs. number of charge cycles. It is a good example of how data presentation can define - and

limit - our ability to understand w hat is really important.


John C. Crowther wrote:

Re. Charging / Discharging of Lithium Batteries - and useful life of the battery

The Article and many of the Comments, as w ell as stressing prevention of overheating, (in a hot computer or a hot car) seem to indicate that length of battery life is a matter of how much

you discharge the battery, and how often you charge it. So it can take 500 cycles of total discharge (100% discharged to 0%) or 4700 cycles of 10% discharge (100% charged

dischragd to 90%). [see exchange betw een David & Paul on April 07, 2011] They agree that the amount of w ork done by the Li-battery is pretty much the same w hatever approach you

take.

Many of the comments focus on avoiding overcharging - and some recommend keeping the Li-battery around 40% - 50% discharged, and topping it up frequently. Sounds like f you dont

use it, you lose it

So far so good. But I have a confusion w hich is (unless I overlooked something - w ant to avoid a f lame from derp). I am concerned about undercharging a Li-Battery. This concern

relates to a Lenovo Thinkpad system, but I imagine it could apply to many other Laptops.

I have a ThinkPad W520, and since the mains adapter is a brick 17cm x 8cm x 3.5cm w eighing 750g (6.7"x 3.2 x 1.3 w eighing 1.64 lbs) I f igured from suggestions on thinkpads.com

Support Community (http://forum.thinkpads.com/view topic.php?p=628326) that I can equally use a smaller mains Adapter also

available from Lenovo.

The Brick has an output of 170W, 20V charging at 8.5A

The smaller versions have an output 90W and charge at 4.5A

so accordingly I bought a Lenovo 41R4494 Ultraslim Adapter w hich is 11.5 cm x 7cm x 1.7cm and w eighs 377g (4.5 x 2.75 x 0.67 w eighing under 12 ounces). I felt very pleased.

But now my ThinkPad is nagging me each time I sw itch on or close dow n:

ncorrect AC adapter is attached.

This AC adapter may not provide enough pow er to your Thinkpad. Please reconnect the proper AC adapter.

i.e they mean I am ndercharging the battery, right?

(Thats true, if I leave the UltraSlim attached w hile I w ork, the battery runs dow n.

Question: But is that bad? Maybe it runs dow n more slow ly, than if the UktraSlim Adapter is *not* attached? Can it damage the control circuits in the battery or the mains adapter?

My compromise w ork routine uses the Li-battery for my w orking day, and I charge it overnight.

1. I hibernate the computer - w ith remaining charge in the battery ca. 30% - leaving it plugged in to the UltraSlim charger overnight.

2. In the morning I unplug the mains adapter, before w aking up the computer (thereby avoiding the nag).

Its back to 98% - 100% - show ing 8 or 9 hours w ork available in the battery (the 9-cell)

During the day, I use the computer on battery, in sporadic intervals of half to 1 hours. Betw een each w ork interval I close the lid to hibernate. I rarely f inish the day w ith less than 30%

charge in the battery.

So now to my main questions:

A. is this routine harmful for the life of a Li-Battery?

B. if not, w hy does Lenovo nag me for using the 4.5A mains adapter?

(it charges OK w hen I am not using the computer).

Many thanks for any insight or light the Team can shed on this subject.

Regards = John


BIKIE wrote:

Hello I w onder if I put my computer w ithout the battery charge and peude after I put my battery during charging is there a risk that the battery or the computer gate

On September 23, 2011 at 12:50am

Dee wrote:

The ow ners of this site deserve praise. great w ork and solid information.


Ashfaq wrote:

hi

I heard the battery life reduces if w e keep the charger plugged-in (charing) after the battery is 100% - is it true?


banmeet singh wrote:

After discharge the battery should be fully charged back because

1. Charging back to 70% restore the life

2.Prolonged discharge state of the plate causes sulphation

3. Partial charging after deep discharge is also causes sulphation

4.,Both B & C


Peppe wrote:

Hi,

I f ind this article very interesting. With the aim of trying to put it in practice by moving to a more sound maintenance of my Li-ion batteries, I w as quickly listing them in my mind: I ve Li-Ion

batteries on my notebooks (Asus and MacBook Air), my tw o photo-camera, my videocamera, my mobile phone.

So, tw o main insight I w ant to apply: 1) never leave a li-ion battery inactive for too long time (i.e. months), but keep electrons move from time to time; 2) store the battery at the best

possible conditions, i.e.: low temperature, low humidity, about 40% of charge.

I should have no problems w ith mobile phones and notebooks, as I use them everyday so keeping them at about the charge level I w ant is something I can somew ay control (plug/unplug

them appropriately). The only problem is the Mac w hich heats often and theres no w ay to remove the battery if I w ant to give it some relief.

The real problems are w ith the photo/video camera: I dont use them everyday, sometimes I dont use them for a few months. How can I simultaneously apply both insights ?

Suppose I charge them to some 40% (diff icult to control, at least w ith the photo-cameras, w hile the Sony Videocam has a progress bar), and then I remove from the devices and leave

them apart. I then go to re-charge them after 1 month (insight 1). How much charge can they loose in 1-month ? I imagine few enough so that to bring them back to 40% I should leave

them plugged in 10 minutes ?

Is this something sound and w orkable ?

Because if not, then I should charge them more and then artif icially use the devices intensely to make them discharge the battery again at about 40%. Thats because I dont know if theres

any universal charger/discharger that I can use to control how much charge/discharge I w ant to apply to a li-ion battery before I store them.

All this is so much easier w ith the Ni-MH Hybrid batteries (used in strobes for example) for w hich Ive bought a Maha Pow erex MH-C9400 charger/discharger and every few w eeks I run

a Refresh&Analyze; cycle specif ically designed for optimal storage of the batteries (then, every few months I run another stronger program to fully re-generate them).

Peppe


Mr.Milcho wrote:

Thanks to Battery University for this information.


Cedric wrote:

The table show s numbers of cycles for different DoD.

But does 50% DoD mean cycling the charge betw een 50% charge and 100% ?

Given w hat the article says, w ould it not be best to cycle charge betw een 10%-60% for example ? (avoid full charge to not have high voltage in the battery) ?

And w hat I w ould like to know is w hat is best (ex. during w orking hours, at my desk) ?? :

- let the laptop/phone plugged, so w ith battery near 100%, but almost not used (except for peak pow er use, such as in phones for some radio communications).

- Or only plug sometimes, maintaining charge beetw een 20%-80%. In this case w e have low er voltage, but the battery is much more in use, enduring more (partial) cycles.

Note that for phone, they w ont w ork w ith battery pulled-off. I w ish it could be set up to only charge to a partial charge (ex 75%).


Tom wrote:

Very Useful


Andrew wrote:

Hi - I have read this forum over various times and have seen the question can Lithium Ion batteries be restored/saved? asked a number of times. Often the discussion leads in tlo

technical descriptions but no clear answ er

Once they no longer hold a charge, is there anything I can do to practically revive a lithium ion battery or is is straight to the garbage dump?

its just that i have a very large pile of, w hat w ere, high quality battery packs and w ould like to know if i can ever derive an practical use for them? ...beyond being paper w eights?

i just f igure that these 14.4v, 95Wh unite cost a bundle and certainly their must be a w ay to restore themno?

please appreciate that w hile mechanically advanced, in the battery w orld Im very much the lay person


Sergey Verlinski wrote:

Could you please explain: w hich mechanical parameters describes aging of batteries? And second question: how Youngs modulus of Li batteries changes depend of temperature.

Thanks in advance.


Michael Nolting wrote:

I just w ant to know if keeping my laptop w ith li batteries connected to the AC charger is destroying my batteries.

I replaced my battery because it w ould not hold a charge in June and now it behaves very erratically.


mekong_nam wrote:

w ell.The information that you give is different from users manual of cellphone company. They said that user should full discharge, empty their battery before recharging to keep battery

lasting longer. All sellers said that users should charge their battery 8 hours for f irst 3 times to maximize the capacity of battery.


Clement Lee wrote:

My Portable DVD is using Li-Polymer rechargeable battery. It is about 1.5years old. Now the battery sw elled and the charge capacitive drop seriously.

Why the battery sw ell ?

Is it dangerous to keep on charge and discharge it ?


resg wrote:

My mobile accepts charging both using AC adapter or USB port. Using the USB w ill apply a slow er charge as stated in the ow ners manual. Question is: is the USB charge less stressful

than the one w ith AC adapter? Is it better for the battery at all?


Martin wrote:

So does anybody know if this article has been updated from 2001 to include more recent info?

As far as my logic goes then at least in 2011, its ok to keep your laptop plugged in w ith the battery attached, because

1. if you charge to 100% and keep to AC on the charger is intelligent enough not to really start charging the battery again until it naturally drops to about 95%

2. w hile on AC the laptop does not draw pow er from the battery (source Dell homepage)

You have to keep in mind though to discharge it / charge it once in a w hile (from this page here it seems the best is to let it go to about 25%?).

Only if your laptop gets very hot w hile using it on AC, is removing the battery a good idea as a hot laptop w ill also naturally heat up the battery (remove the battery and touch it, should

give you an idea). This, as I understand, w ill make the battery loose its capacity more quickly.


David Jones wrote:

Ive just f inished reading the article and all comments. Not until nearly the last comment did I learn that the article w as w ritten in 2001. I scrolled back up and found no date before or after

the article. My closest clue w as w hen the comments began in 2010. My fault for no thorough research of the source. I simply Googled how to care for Lithium Ion batteries. I must say

that I appreciate the intelligent comments, especially Paul and Walter. Many thanks for this information. My Toshiba laptop and cell phone batteries w ill serve me longer and stronger.


megan wrote:

i left my phone in outside and i fount it everything w orks f ine but not less than 5 seconds after i turn it on it says battery is to hot pow ering off??? does anybody know w ht tht means ???


Ted Seifert wrote:

How do I store my lithium batters for the w inter, I use them in my yard tools. I w ill not be using them for about 4 to 5 month.


cristovian wrote:

Can a battery, namely Li-ion be charged and discharged at the same time,w ithout a disruption in the output. The battery pack has tw o terminals one input and the other one an output.


[email protected] wrote:

I just bought a Craftsman 20 v Li-Ion Professional drill (display model). When I got it home I tried to charge it and the charger indicated that it w as defective and refused to give it a charge.

So I stuck it in the freezer for a short w hile and then it charged ok.

Does anyone know w hy this happened?

Does anyone know if the pack is good or should I return the drill to Sears.

Thanks for any replies


Zubair Shahid wrote:

Hi! I have a dell inspiron 1520 laptop. I have a question. If i use maximum time laptop on ac state although my battery is full so is it harmful for my laptop or my battery plz guide me


HHAH wrote:

very helpful, thanks very much


brian wrote:

Laptops get hot w hen turned on especially bigger ones w hen the CPU and video cards are processing a lot of data. It can be detrimental w hen turned on 24/7 as the battery also

maintains a 100% charge. Placing laptops on blankets or beds can block the vents and overheat it further. Fabric is also a good insulator. If laptop batteries are protected from excessive

heat w hile running, w ouldnt the service life last much longer.

The advantage of Li-ion is that it is light. I prefer NiMH because apparently, they dont age as fast w hen not in use and they dont have that explosion risk.

mAh can be a bit misleading because it does not equal Wh. Wh is equal to V x Ah. So it seems if you connect cells in series, you f ind the Wh of each cell before adding it.


Ray Wells wrote:

I have a Samsung Galaxy, and left it charging overnight using the USB port of my HP Mini, w hich w as plugged in the w hole time. In the morning, the phone w as good, but the laptop battery

w as 0% and has not w orked since. My theory is the USB port stayed pow ered w hile the laptop cut its ow n charger off for some reason. Before this, the laptop battery w as doing f ine.


Katy wrote:

Well from first hand know ledge the quickest w ay to kill your Lithium Ion battery is to let it go completely dead. Another thing is to leave it in the car over night in the cold. Just trying to help

so you guys dont make the same mistake.


Guillaume wrote:

@Sandeep

If you intend to use your laptop charged in for an extended period of time, remove the battery from it at 40% capacity.

You should not keep the battery on the laptop. The laptop w ill keep charging the battery as soon as it losses a little capacity and w ill eventually reduce the battery life expectancy.


Guillaume wrote:

So if I understand the Table 2 correctly, the optimal capacity to charge a Li-ion battery is 50% ?

100% * 500 cycles = 500 times full capacity




Did I miss something ?


taz wrote:

Dont listen to these people thats crazy there saying if u store ur battery in ur fridge at 0c your battery w ill only lose 2% per year? So i can store my lithuium battey for 10 years and lose

only 20% capacity? LOL


Mike McMahon wrote:

My cell phone battery is Li-Ion 3.7 vdc. My USB output is 4.98 vdc. Is the 4.98 v going to signif icantly degrade the life of my battery?


Ray Wells wrote:

The underlying issue is how humans should behave in order to handle technology. Well, guess w hat, thats backw ards. Technology should behave in a w ay that humans can deal w ith.

Assume they are all retards if you like, but expect them to: 1/ Leave rechargeable devices plugged in most of the time, 2/ Leave the battery in place w hen in use, regardless of being

plugged in. 3/ Store things in a hot vehicle w hen convenient. 4/ Need a clear indication w hen a battery needs replacing. Like everything else, battery technology w ill evolve by natural

selection. Utility and economics.


Ray Wells wrote:

I liked the original article, gives a good analysis of the challenges facing the industry. There w ill probably alw ays be 101 things to avoid doing w ith any battery technology.


Du Roi wrote:

I have a Nokia N70 Me for several years (may be 4 or 5) w ith a Li-Ion (BL-5C) battery, w hat i use to do is to charge 100 %, and use phone until the battery is full discharge. My BL-5C is in

perfect condition i assure you. This is my ow n experience w ith a Li-Ion phone battery, and i think this contradict a little beat some of this theories. I hope this help in a w ay or another.

Happy New Year for all !!!


Ray Pipkin wrote:

@ Jeff Simon, w ho w rote:

Maybe I am the only one missing one aspect of the number of cycles verses depth of discharge: if you only get 500 cycles w ith 100% discharge, as compared to 4700 cycles w ith 10%

discharge, those cycles are not equivalent.

That is, the 100% discharge got 10 times the pow er ouput as compared to the 10% depth. If assuming useful w ork w as done in each depth, then in fact getting 500 cycles actually gets a

bit more w ork than 4700 cycles of only 10% the depth.

You are correct in your observation, but you should have taken it one step farther. Using the data of Table 2 w hich gives the number of cycles to 70% capacity as a function of depth of

discharge, one can derive the relative amount of total energy extracted (a dimensionless quantity) from a Li-ion cell as a function of DoD:

100% DoD yields 500 units of energy from a Li-ion cell over its useful life;

50% DoD provides 750 units;

25% DoD provides 625 units; and

10% DoD provides 470 units.

The data in Table 2 indicate that recharging w hen the capacity reaches 50% is optimal over the other three options.


Inpulpded wrote:

You can think of your computers registry like the brain of your computer. As such, it stores facts not only on every program that your computer has set uped at any given time, it also

tends to keep information from programs that you Formerly take aw ayd. This can be a important problem for PC ow ners and is w hy its imperative for computer users to use a free

registry cleaner.

When you set up softw are on your computer, some important records are stored inside your computers registry. How ever, w hen you eliminate or unset up softw are, sometimes those

data remain inside your registry. Maybe the softw are w as poorly w ritten or your computer had a hard time unset uping the softw are properly. In either case, the end-result is that you

have information in your registry that are no longer needed.

advanced system care torrent

cleans your computers registry. Registry cleaners get rid of outdated and errant registry entries that can cause PC slow dow n, error messages and even softw are crashes. serious

registry problems can even result in your computer becoming unbootable. So, by employing a registry cleaning tool, you can w ork to eliminate these PC slow dow ns and avoid future

problems due to a bloated registry.


Deyan wrote:

I have ow ned an Acer Aspire laptop w ith a Li-ion battery for 4 and a half years now . I use it predominantly on AC pow er and NEVER take the battery out. My battery now still has 86.9%

of its initial capacity. Any comments? derp, w hat do you think?


Eric wrote:

If you look at table 2, it only says the number of cycles, w hich is irrelevant here. If w e have a charger ready and need to know w hen to charge to prolong life, you cant read it from the

table directly. If I fully use the battery until its empty (100% DoD) you have to compare that to 10 cycles discharging to 10% DoD, because thats fulf illing the same usage; any other

comparison is useless. So looking at these four values, the 25% DoD seems to be the best, but more values w ould be helpful.


jessiefister wrote:

dont charge your battery untiil it is used up.

more ideas please click:

http://w w w .batterymag.co.uk


Luke Patrick wrote:

I w ork research and development and have tested lithium-ion cells for years. Here are some points I have learned on lithium ion:

0. If a battery is in a device, the device alw ays has some sort of battery management system. Full discharge (to 0 volts) should not be possible and does cause irreparable damage. full

discharge to about 2.7V (0% state of charge) is normal.

1. Storage w ill not rejuvenate or recover capacity.

2. If you need to store long term, store it at 50% charge. This reduces self discharge and/or active material degradation.

3. Freezing can damage a cell by causing dendrites (crystalization) in the electrolyte components and piercing seperator or damaging material bonds.

4. The low er the operating temperature - the slow er the ion exchange.

The higher the temperature - the higher the material degradation. Room temp is best.

6. Once in a w hile, discharge the battery until the device cuts it off, fully charge it and leave it on the charger for a short time. This moves as many ions as possible from one electrode to

the other keeping them free to move instead of stubbornly stuck.

7. Remember different companies make different formulations of Lithium ion and Li-polymer that behave differently like High pow er, High capacity, long life ... there is alw ays a trade off.


shane wrote:

charge my battery


Karen wrote:

I just moved to a new off ice. Since moving my cell phone battery discharges (totaly- phone w ill not turn on) after about 3 hrs in the off ice w ith no use. It has never done this and now

does it daily. There are several radars operating w ithin 1/2 mile. Could they be causing this? Tempature is cool and humidity is about 20%. The person w ho had the off ice before me

said it did the same to her. It does not affect my IPad or Laptop. What could cause this and Is this damaging my battery? Thanks


BigMart wrote:

I am even more confused now than w hen I started (not diff icult!). I used to use my Acer 5715Z series laptop battery running it off the mains all the time, w here practicable. Now I let it

virtually fully discharge and then fully recharge. I now believe that it is w rong

So I am to let it discharge to 50% and then recharge it back to 70% ???

Is it okay to run the laptop w ithout the battery inside?

Please help a simpleton !!


Guillaume wrote:

@BigMart

You w ant to run the laptop w ithout the battery if you can. Dont leave the battery in the laptop w hen you are connected on the 120 Vca. A poor battery charger w ill reduce your battery

life w ith an bad charging method.

As it w as said earlier, the optimal charge level is around 50% of the battery capacity. You dont w ant to go crazy w ith your laptops charge level. I suggest you to use the laptop betw een

40-100% of your battery capacity and then recharge it.


BigMart wrote:

Thank you Guillaume for your comments.

I am afraid you are bit too technical for me! What is 120 Vca ? The battery charger is w ithin the laptop.

So I charge it up 50%, ie w hen it indicates 50% left. So w hat is 40-100% then?

As you can see I am so confused !!


BigMart wrote:

Would you agree w ith this suppliers instructions?

http://w w w .ebay.co.uk/itm/w s/eBayISAPI.dll?View Item&item=290565009405&


Pavlo Maksyutenko wrote:

The smaller the depth of discharge, the longer the battery w ill last

is WRONG based on Table 2. Battery life = (number of cycles)x(depth of discharge). Table 2 show s that 50% DoD is the best.


BigMart wrote:

So w hat are you saying Pavlo? Discharge to 50% and then charge up to ???


John Fetter wrote:

On December 22, 2011 Ray Wells w rote, Technology should behave in a w ay humans can deal w ith. He is 100% right. If batteries are pow ering computer equipment, it should be easy

for equipment manufacturers to include programming that learns how the equipment is being used and to control battery charging accordingly for maximum life.

Simple. Unambiguous. The equipment w ould then be left plugged to a mains supply as much as possible. It w ould automatically apply optimum charging. If it detects excessively long

absence from a mains supply, it w arns the user.

They are not doing this simply because they w ant users to be confused and they w ant batteries to stop w orking, on average, just out of w arranty, so that they can sell more batteries.


Des wrote:

A very in formative w eb page. I must admit that I have more than I knew about batteries. I w ill refer your site to my friends.

Thanks to all for your w onderful contributions.


BigMart wrote:

I w ish someone could give me simple answ esr

.

I just w ant to know if I am running it on battery pow er how long I should let it run dow n to - and then do I recharge it to full pow er. If I am running it through the mains do I take that to full

pow er? When running it on the mains do I take the battery out?

Thank you.


John Fetter wrote:

Go to supermarket, pick up something from the fresh produce section. it carries details about the contents, cooking instructions, etc. Buy something w ith a battery, it carries instructions

that look remarkably like threats. Dont do this, dont do that. Will burn, w ill explode. Hey, I just w ant to know how to use this thing!


Guillaume wrote:

@BigMart

Dont let it drain out to maximize life expectancy. When you reach 25-40% remaining capacity, you should start recharging it.


BigMart wrote:

I concur w ith John Fetters comments. Is there nobody out there that speaks plain English?


BigMart wrote:

I take a coach / train journey every few w eeks w hich lasts approx 2 hours. I use it then on battery pow er. When I reach my destination I can then use mains.

So should I just run it off the mains w hen practical (removing the battery f irst?), or use battery pow er, but w hen I am dow n to 25 - 40% (a big range), plug it in until it reaches maximum?


Guillaume wrote:

@BigMart

With that kind of use, I w ould recommend to recharge the battery the day before your coach / train journey. You may leave the battery at w hatever remaining capacity for a few w eeks

if this capacity is over 25%.

If the remaining capacity is below 25%, recharge it until it reaches 40% and then store it until the next utilization.

Also, I suggest that you remove the battery from the laptop for an extended use on mains.


BigMart wrote:

Thanks Gullaume

As I w ill be using the laptop over a couple of days, so I w ill need to charge it up, use it on batteries then use it on mains until it charges up again. So should I continue this process until I

get home? I w ill w ant it fully charged for my return journey.


John Fetter wrote:

My company w as running a product ad on line that had absolutely nothing to do w ith lithium ion batteries. We inadvertently w orded it in a w ay that w as interpreted by unhappy lithium ion

battery users to mean w e could help them. The effect w as like a tsunami. They clicked aw ay the a

Documents

How to Prolong Lithium-based Batteries - Battery University