Lithium (li-on, lion) batts capacity/maintenance/conditioning

Was reading up on Li-ons on Wikipedia after 'arguing' with a customer service officer at Creative that Li-ons had no memory effect and did not like deep discharging (which he advised to do).

http://en.wikipedia.org/wiki/Lithium_ion

Other than our common discussions here on CPF about Li-on maintenance (i.e Avoid charging more than 4.2v, avoid deep discharge, no memory effect etc), apparently Li-ons will just age and lose some capacity even if they are not used.

I quote :-
"A unique drawback of the Li-ion battery is that its life span is dependent upon aging from time of manufacturing (shelf life) regardless of whether it was charged, and not just on the number of charge/discharge cycles. This drawback is not widely publicized."

Those batts from AW and other vendors... anyway to tell their manufacturing date? I don't see anything on the wrapper and I'm wondering if anyone has noticed any markings if the wrapper is removed.

Although it's kinda fun to do all these batt tests, it's kinda hard to monitor each and every batt when you have a lot and when you're out for a long trip or some operation, you want to make sure you have the best batts installed. These little characteristics of rechargeable batts are making it hard

I think a good ol' primary cell is still the easiest way to go to know that you have a fresh cell with lotsa charge (assuming voltage is approriate etc...).

Re: Lithium (li-on, lion) batts age adds to capacity loss

well,
nothing new, or?

except for the "xx % loss" with deep discharge.
In my observation, with the 1st discharge under 2.5 Volts/cell, the batt is killed (if not killed, then damaged so far, that it is no longer useful)

Re: Lithium (li-on, lion) batts age adds to capacity loss

I label the month/year I receive mine right on the battery. It's better than nothing. I've always did that...don't know why.

Jeff

Re: Lithium (li-on, lion) batts age adds to capacity loss

yup, current LiIon's have a limited number of full cycles that they can do before the charge possible really starts to drop off (in a hard use device it is normally 250 to 300 cycles, running the battery info program on my powerbook shows that I've used 145 cycles on this battery and it is still holding 96.6% of it's stated capacity) and they also have a limited lifespan, used or not. With some batts it seems to be as little as 18 months before you'll start to see a real drop off in capacity, others I have here have been in daily use for 2.5 or 3 years and are still going strong.

And a deep discharge will kill a LiIon fast too.

Re: Lithium (li-on, lion) batts age adds to capacity loss

Li-Ion is a relatively new technology.

I have seen many wrong information, even from authoritative sources, on the life cycle and self discharge of Li-Ion.

One of the legends is that the life of Li-Ion is set, and starts ticking as soon they leave the factory.
I have some Molicel 18650 nine years old, with one thousand shallow cycles, still at the original capacity.

Another legend is the Li-Ion lose 5% of their charge in the first 24 hrs after being recharged.
If you recharge a Li-Ion without any temperature rise, it will lose 5% of its charge in six months.

Li-Ion is a new wonderful technology, and there is a lot of room left for improvement. Since Li-Ions present an inherent risk of self-ignition, they are only sold in battery packs with electronic protection, and that adds many features (like the life timer, or the discharge equalizer) that are wrongly attributed the the Li-Ion cell itself.

I'm collecting experimental data on Li-Ions since four years now, and all I can say at this stage that I have found many discrepancies between what is published on the net, and the "measured" reality.

As generic experimental indication, the single most important factor influencing the life of Li-Ions it the charge temperature. People kills laptop packs by immediately recharging after hours of continous use. If allowed to cool down before recharge, the life of the Li-Ion battery will extend noticeably.

Anthony

Re: Lithium (li-on, lion) batts age adds to capacity loss

James S said:

yup, current LiIon's have a limited number of full cycles that they can do before the charge possible really starts to drop off (in a hard use device it is normally 250 to 300 cycles, running the battery info program on my powerbook shows that I've used 145 cycles on this battery and it is still holding 96.6% of it's stated capacity) and they also have a limited lifespan, used or not. With some batts it seems to be as little as 18 months before you'll start to see a real drop off in capacity, others I have here have been in daily use for 2.5 or 3 years and are still going strong.

And a deep discharge will kill a LiIon fast too.

Click to expand...

Your Powerbook's battery preformance might be normal. (Believe it or not). I have a good friend who owns several IBM 760s and they have batteries from 1994, and they're still going for 2.5 hour runtimes on his laptop.

Re: Lithium (li-on, lion) batts age adds to capacity loss

I checked a 5 years old Panasonic 18650 1800mah cell:

1600mah, thats a nice resultat!

zelda

Re: Lithium (li-on, lion) batts age adds to capacity loss

Your Powerbook's battery preformance might juts be normal. (Believe it or not). I have a good friend who owns several IBM 760s and they have batterys from 1994, and they're still going for 2.5 hour runtimes on his laptop.

Click to expand...

I am happy with "normal" when so many laptops so abuse their batteries as to make them die a quick death. I was using a laptop as kind of worst case usage pattern for LiIon batteries. They get cycled a lot, run hot, charge fast and run all the way down. I have another one that is the original from this laptop that is down to 91% with over 360 cycles on it, so they really do a good job of taking care of the cells.

But as has already been mentioned, it really matters how well the device and you take care of them as to how long they last. Some people get 3+ years out of an iPod battery before they notice any lowering of capacity, other people only a year. It's not number of cycles, but temperature and habits that affect it a lot! Just sitting in a box though, they wont be good in 10 years for anything other than landfill.

Re: Lithium (li-on, lion) batts age adds to capacity loss

Thanks for the answers guys.

Anyway, the Creative technical department wrote back and were telling me that I might not have charged my batt fully when it first came, and to recondition the batt, I would have to 'drain' it by playing my device till it was flat, then turning it on again and playing it some more till its really flat.

Whereafter, I can start charging the batt for abour 4-5 hours and the batt would be somewhat 'reconditioned'. Is that true? I thought Lithiums hated to be drained to the last drop and shouldn't be put under this kind of treatment since dropping it below 2.5v will prob kill it.

If it has no memory effect, why do we have to drain it first?

Also, even the latest mobile phone and mp3 players' manuals require the 'first charge' of 8-12 hours. Do Li-ons need some kind of conditioning in the first few charges, like NiMhs? Or are they ready to go straight from the factory?

Thanks!

"memory effect" is usually mislabled.

cycling a aged boored unused li-ion or li-poly can have it work better. there is no reason to cycle it on purpose or anything, i just have proved that, to myself.
cycling it WITHIN its specs when its been parked , will increase the speed of discharge capacity or capacity.
something like that.

i heard that they dont advantage from cycling, and if your USING them they certannly do not, but i proved that cycling aged unused ones made them more vibrant, including longer run times.

discluded cycling a set of SERIES batts that might not stay or get BALANCED, so if its a SINGLE (like cell phone pda mp3) then you might get an advantage from a cycle, which your going to do ANYWAYS by just using it. but if its a 7.2v pack with non-balancing protection, then cycling it might go totally against it, further inbalancing it, i donno, just know that singles can be "revived".

on the other hand you would never want to deep or flatten it, only discharge it to the 3v or so when there is no capacity left, don't over-do it either, like re-turning the device on , and back on again, unnessisary.

if it goes flat they go bad, that is the one thing that seems to kill them faster than anything a full discharge, which usually is stopped by the protection curcuit, in most packs.
and recharge it after it is down, when cycling, as opposed to waiting days to recover it.

and, because of what kills it when it goes flat , i would charge it first, before doing any cycling. because the metal gets thin or something when they go flat, so if its just been parked , charge it then cycle it. or (again) just USE it

all the other stuff is To REAL, they are lasting longer than they are speced for when treated right, especially treated right by the curcuit there to protect them, like a GOOD laptop pack that can stay balanced.

I was a Toshiba-authorized portable PC repair tech about ten years ago. They used Li-ion battery packs in all their units, and one of the biggest things we had to deal with were new-from-the-box batteries that would only recharge to like 15 minutes of use when new. After about five cycles they'd level off and run the PC for the advertised time... and would do so for several years.

We used to explain it to people analogizing it to getting your arm out of a cast... takes a little while to "stretch it out" and regain full use. Seemed like a satisfactory response for us and by us.

At what point in time do you take a voltage reading to qualify a "deep discharge" ?


For example, a li-ion immediately taken out of a light under load may read ~2.4V and then left alone (no load) 3 minutes later reads ~2.9V.

When is the votage drop below 2.5V an issue?

Hello Randy,

It is my humble opinion that if you read under 3.0 volts when you immediately check a Li-Ion cell after use, you have over discharged it and have done some damage...

Tom

the advice to deep cycle the battery is likely to reset the management chip in the pack.
if you run to lvc the chip gets recalibrated and then reads what gets put back up to hvc.
most consumer level (cheap crap) lacks this kind of management.

so have we managed to decide if it is wise to deep cycle (because it recalibrates the protection circuitry) or unwise (because overdischarging damages the cell)?

If you have a pack with the little computer in it that keeps track of the charge, like a good laptop battery, then running it down till the laptop goes to sleep does recalibrate the counter, but it's not a "deep discharge" from the batteries standpoint. The whole point of having that level of protection circuitry in the pack is to keep the batteries from over discharging and all the rest.

So it is just counted as a full cycle when you discharge to that level, not a "deep discharge"

Of course, certain computer pack manufacturers may push that limit a little to try to get more capacity out of the pack. The focus seems to be on battery lifetime between charges and not battery lifetime overall.

I'm not sure how protecting circuitrys differ between 'good laptop batteries' and those in protected 18650s for example. Does the same principle apply for individual protected 18650 Li-Ions? Does discharging them as far as the protecting will allow and than recharging them fully recalibrate the protection circuitry?

Re: Lithium (li-on, lion) batts age adds to capacity loss

James S said:

I am happy with "normal" when so many laptops so abuse their batteries as to make them die a quick death. I was using a laptop as kind of worst case usage pattern for LiIon batteries. They get cycled a lot, run hot, charge fast and run all the way down. I have another one that is the original from this laptop that is down to 91% with over 360 cycles on it, so they really do a good job of taking care of the cells.

But as has already been mentioned, it really matters how well the device and you take care of them as to how long they last. Some people get 3+ years out of an iPod battery before they notice any lowering of capacity, other people only a year. It's not number of cycles, but temperature and habits that affect it a lot! Just sitting in a box though, they wont be good in 10 years for anything other than landfill.

Click to expand...

Discuss the Ipod. I have one that has really gone down in capacity, are there replacement batteries for the Ipod and who does that kind of work?

Randy Shackleford said:

At what point in time do you take a voltage reading to qualify a "deep discharge" ?


For example, a li-ion immediately taken out of a light under load may read ~2.4V and then left alone (no load) 3 minutes later reads ~2.9V.

When is the votage drop below 2.5V an issue?

Click to expand...

depends on what its at resting, or how far the capacity is really down.
check out silvers charts on how much capacity is actually left at certian voltages.
if you took it down to 2.4 or rested 3.0 then recharge it soon.
you dont want to leave it low , so i have not tested that, other than accidentally testing it dropping way to low for to long, and then it is DEAD, totally wiped out.

i have tested dropping to protection end, with rest of 3v , and it was a ok deep discharge, but to LEAVE it there. or to say have it go ACTUALLY to 2.4v with a slow LED discharge , might not be soo good, it's very low.

there aint much left in them at 3V with a light load, so there is no good reason to go much lower than that, UNLESS there is a heavly load.
and that is probably why the protection cuts off SO LOW, because if you had a 1or 2c load on it, the voltage would drop lots further.
also with protection remember there would be some resistance, just a bit, but that also would drop voltage under load.
with a heavy load, the 2.4 v dropout would Still occur when the capacity was shot, even if it then would rest back up at 3.2v

EX: if its a DD white led, or a psudo DD white led (resistered) then when it goes really low, pull it then, or be prepared to recharge it quite quickly, as opposed to days later. did that many times, worked ok, i pull before its totally dead just because it takes so long to drop completly.

Re: Lithium (li-on, lion) batts age adds to capacity loss

cobra-ak said:

Discuss the Ipod. I have one that has really gone down in capacity, are there replacement batteries for the Ipod and who does that kind of work?

Click to expand...

Check out batteryspace.com, they have a few ipod repacements, for different models. also ebay sellers have some ipod replacement batteries. with this caveat, it may LOOK like e-bay sellers might have much higher capacity internal replacements, and it is often not true.
if you can get the replacement from a trusted source, it is just as likly to be as large a capacity as you can get.
Meaning, i have goten a lot of replacement batts from china and american sellers at e-bay that were rated totally wrong, even listed totally wrong, for what it Said right on the battery when it arrived.

replacement is very simple, with the connector ones (with built in protection). i havent done an ipod, but i use the ipod batt for some things, and have replaced/upgraded pda ones.
just a matter of getting the leetel screws out, un snapping the cases, and locating the battery , and pulling the connector without tearing stuff up, and re-securing it the way it once was. the battery could be stuck down good, with 2 sided tape stuff, just remove it slowly letting the glue releace, as opposed to pulling to fast and hard.

its one of them "nothing to lose" propositions , for the price of the unit, you can have sombody do it, or for 1/5th that you could potentially lose the unit. and once you learn your 100miles ahead.
just pre-measure the size, check the capacity before purchaces, as sometimes that stuff aint returnable, then you will have to make a flashlight with it