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how to prolong a Li-ion battery's life?

by thefarseer / July 21, 2005 12:37 PM PDT

I have a Nokia cellphone powered by a li-ion battery. What should I do to prolong the battery's life? The sales person told me to charge the battery when it has only one bar left. When I do my research on the internet, it was another story. The website ( suggested that I charge the cell phone as often as I can. Im looking for a third opinion.


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(NT) (NT) A nod to battery university...
by R. Proffitt Forum moderator / July 21, 2005 9:46 PM PDT
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Li Ion
by stewart6 / July 24, 2005 3:04 AM PDT

Your sales person was telling you the charging proceedure for batteries such as NiCads that have memory effects. That is if charged from say a three quarters charged state, then the battery will only discharge to the threequarters level.
Lithium Ions are claimed to have no memory characteristics so, at least in theory, you shouldn't have to worry about when to charge.
However most of the laptop manuals I've read still suggest running your battery right down before recharging. I don't know if this is a hangover from previous practice but if you want to play on the safe side, Follow the old practice. Best regards Stewart

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Li-ion Batteries
by zerotonin / July 29, 2005 2:25 AM PDT

I worked for a cell phone company for 8 years and did a lot of research on this subject so I could properly inform my customers. There are basically 3 types of chemicals currently being used for cell phone and laptop batteries. Ni-cad, Ni-mh and Li-ion. There is a fourth makineg its way in Li-ion polymer. A couple things are consistent for all types of batteries no matter what chemical is inside. You must initially give the battery a 12-14 hour charge on the home charger. (Don't use a cigarette adapter for the first charge. This conditions the battery and don't take it off the charger that first time even if the charging indicator says it's full after 3 hours. Also the manufacturer's also state to run it thru 3 charge cycles. What that mean's is that you fully charge and fully drain 3 times. 1 full charge + 1 full drain = 1 charge cycle. Here's where the way you charge the battery starts to differ.

Ni-cad: Mostly only on older devices, has a "memory" effect, should be drained before a full charge is put on it, should be removed after overnight charge or can be overcharged and burnt out.

Ni-mh: Still used for some devices, has slight memory effect but not enough to have to fully drain before the recharge, should not be consistently left on charger after full charge that can eventually burn out battery and shorten usage time.

Li-ion and Li-ion polymer: Used on a lot of newer devices, has no "memory" effect, should be recharged as often as possible, actually likes to be charged and draining it regularly can cause the usage time to be shortened, can NEVER be overcharged so whenever you're near a charger put it on there. Besides those benefits a li-ion battery is lighter and smaller but the chemical can hold more charge than Ni-cad and Ni-mh.

So the one reply to your question said to error on the side of draining the li-ion batteries. This is incorrect information. You want to charge the battery before it gets below a 20% charge. Also batteries will not go bad from accidentally doing the incorrect charging procedure here and there but normally follow the correct procedure. One last note try to use the home charger more often than the cigarette lighter charger for best long term results. Cigarette lighter chargers do not give a full charge (about 95%) which in the long run can damage any type of battery listed.

Hope this helps

P.S. Every battery will have those abbreviations to tell you what cehmical is inside the battery, even rechargable power tools which these charging procedures apply to also.

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by mileschap / July 29, 2005 4:21 AM PDT
In reply to: Li-ion Batteries

After again reading I am still not certain. I have always been under the impression that the battery should be discharged about 80% prior to recharge. Why, I'm not certain.

Perhaps Li-ion bats do not operate the best, or last as long, if fully discharged prior to recharging.

I also understand that battery lifetime is partially determined by the number of charges. That being the case, discharging as much as possible would be the correct answer; however, bowing to the opinion of BatteryUniversity, I would guess that taking it down 80% or perhaps 2 bars remaining on your Nokia would be proper. Consideration must also be given to convenience. Do you have a spare battery to quickly replace the discharged battery? If not, and you intend to use your phone heavily one day, or even simply leave it on all day, you can decide what is the safest level to allow it to discharge.


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Charging Li-ion mobioes
by Graham70 / August 30, 2005 9:55 PM PDT
In reply to: Li-ion Batteries

I'm hoping you will be so good as to give me some advice on charging Li-ion mobile batteries.
We supply a means for poor people to have a little electricity far from the mains.

One application is solar charging of mobile phones but this is causing problems with the new Li-ion batteries
now coming into use. For reasons that still puzzle, most phones do not accept our solar charging.

If the battery is removed from the phone to be charged it's okay.
But when inside the phone there is no charging unless the current is over 300mA - which is more than our small panels provide.

I have solar charged Li-ions outside the phone many times with no problems but most clients are understandably doubtful about this!
What is your opinion?

I suspect it comes into the same category as manufacturers who warn against charging dry cells. It's not on their interest to encourage it!

Grateful for any assistance!


Graham Knight
BioDesign (non-profit)

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For Graham.
by R. Proffitt Forum moderator / August 30, 2005 10:32 PM PDT

Maxim (an IC maker) has a LiOn charging circuit which you can use. I've seen shade-tree type affairs that don't have the required circuir.



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Rechargeable Batteries
by batavier / July 29, 2005 5:34 AM PDT

All rechareable batteries have a finite number of recharge cycles, after which they no longer hold their charge. (The technology only defines the availabe amp/hours/volume.) Anything you can do to reduce the number of recharges will extend the battery life. So your saleman was close: Wait till the battery is (almost) discharged, and then give the battery a full recharge.

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Lifetime of rechargeable batteries
by franknemec / July 30, 2005 4:05 PM PDT
In reply to: Rechargeable Batteries

To say a rechargeable battery lifetime consists of a finite number of charge cycles is correct but misleading. The lifetime is determined by how it is charged and discharged, and it is finite. For NiCd, discharge it fully (but not excessively) occasionally, not every time. For Li ion, keep it charged. In all cases, use an intelligent charger that won't overcharge. And use the battery, don't just leave it on the shelf for months.

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Lifetime of the LiON battery powered with solar cell
by haze78 / October 16, 2010 8:30 PM PDT

I built a little project awhile ago. It is a solar garden LED lights powered with single LiON 1000mAh battery. PIC microcontroller is monitoring battery voltage and prevents it to drop below 3V, as well to rise above 4,10V. Charging current is 50mA at max., meaning 0.05C. Maximum discharge current is about 0,02C. My question is, how will forementioned conditions affect battery lifespan. I read somewhere that when charging LiON battery below 0.18C, battery voltage of 4,2V means that the battery is virtually full, is this true?

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A few notes.
by R. Proffitt Forum moderator / October 17, 2010 1:01 AM PDT

1. You posted a new question in an old thread. Not a good idea.

2. All this is usually done with an IC or battery controller chip. If you design your own, you lose all the IC's design benefits.

How do I know? Been down that road.

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consult the manual or manufacturer
by ackmondual / July 29, 2005 5:37 PM PDT

Some cell phone manuals will inclue this info of how to best prolong your phone's Li-ion battery. If not, try calling your phone and/or battery manufacturer for this info on their suggestions.

NOTE: li-ion batteries don't necessarily follow one global rules. E.g. for some stand alone PDAs, it's best to top of li-ion rechargeable batteries. For cell phones, the manual will tell u best to discharge the power as empty as possible before recharging

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Nokia battery still going after 5 years plus
by Shofarman / August 9, 2005 5:33 PM PDT

I have a Nokia 8290 which uses a BLB-2 battery. I normally charge this battery fully, unplug and go and charge it USUALLY only when it beeps which means it's ready to be charged. I have had this same phone and battery for well over 5 years and it still holds a charge for a couple of days if I don't use it (which is rarely the case.) I spend at least 2000-3000 minutes on this cell phone a month and am very happy with the battery life. I sometimes get out of the truck before it finishes charging so sometimes it doesn't get a full charge but I'm faithful to put it back on charge when I get back to the charger. It doesn't seem to matter how I charge it, it still holds a very good charge. Now I also have friends that have newer Nokia phones and they go thru batteries like they are Alkaline batteries. I don't know, maybe I'm just blessed - well actually, I know that I am blessed.

By the way, I use a wall charger at home and keep it on charge till I'm ready to depart the house and in the truck I have a smart charger designed for the Nokia phone.

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prolonging lithium-ion batteries
by NeilFiertel / August 10, 2005 9:35 AM PDT

My digital camera which also uses the li-ion battery says in the manual not to charge it and leave it charged when not being used in order to prolong the battery life. They do better being discharged and stored. Now, of course, one wants a charged battery on a phone so I would suggest that there are limited cycles of charging and discharging. They do not have a memory so it is not necessary to run the battery into the ground but does it hurt it to do so though when you are half off a cliff teetering in balance in your SUV, it would be nicer if that battery were fully charge...right? Just charge away and buy a battery once every few years. Most likely the phone will crap out anyway and the batteries are not yet a standard design.

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How to prolong a Li-ion Battery's life
by paulbaughman / March 13, 2011 12:37 AM PST

That link provides the best advice in my opinion. They have actually done the tests... so... there you go.

You did get one poster here that basically confirmed the information in the link. Frequent re-charges are best with the Li-ion batteries.

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