I found a few rechargeable batteries that had not been used for at least three years. I charged them all and found they do not seem to be holding their charge (unable to power a cordless mouse for more than five minutes).
Is this type of battery destroyed by being left discharged for a long period or could it recover with a few more charges?
It depends.......
I have an HP PDA not used since about 2005 and the batteries won't hold charge.
I have a JVC badged digital camera last used in 2005 with several spare batteries and all seem to hold charge.
So it probably depends on the size of the battery, the chemistry and the manufacturer.
Cheers
Dave R
NiMh and LIPO will in general be destroyed, but Nicad can take it.
Your avvin a laff, mate. Even good quality NiCads would grow whiskers if they were left discharged for any length of time.
Does it matter :)
Gave up using rechargeables for AA AAA batteries years ago. There's no way they saved any money after buying the charger(s) and having the batteries last for a few months.
I wouldn't be surprised if they are less environmentally friendly than regular disposable ones.
In message snipped-for-privacy@4ax.com, Custos Custodum snipped-for-privacy@privacy.net writes
Hum. Connect a charged NiCad in parallel and vaporise the whiskers:-)
My eneloops have lasted much longer than that.
They've save me a fortune on an old rather power hungry mouse.
They may never have been able to power a cordless mouse even when new. Rechargeable batteries have a lower terminal voltage than conventional single use alkaline cells. At low currents this can matter some devices shutdown when the cell reaches a certain voltage to help prevent leaks.
My desk phone display will not run at all on rechargables as the LCDs cannot produce black with the limited voltage. Current requirement is almost nil but without enough voltage the display just doesn't work.
Leaving them flat for a long time or overcharging them will both seriously shorten battery life. Check them on something with a more realistic load like a torch and see how long they can power that for.
Some battery technologies handle abuse better than others and in general the higher the energy density the less happy it is about being abused. It is worth giving them a charge discharge cycle to see if they wake up.
They should last at least a couple of years (or more) if you look after them and use them in rotation. Leave some dead flat in a drawer or continuously on charge and you will more than likely wreck them.
NiCads certainly were. NiHM and Lithium less so but I do wonder about the mining of lithium salts for green electric vehicles being displaced environmental damage of the out of sight out of mind third world sort.
I've not had a single battery fail - that's over about 10 years, with about 30 in use at any one time. And if any have deteriorated in terms of capacity or ability to hold a charge, it's not affected any in a way I've noticed.
NiCd & NiMH aren't worried by sitting flat. I'd charge them, not fit them then fit them to the mouse a week later, see if they've self discharged or whether they then run 5 minutes. Should narrow down the problem. If they're self discharging quickly you can get a bit more life by zapping them, but not much, they soon short out again. AAs & AAAs are 2 for £1 at poundland anyway.
NT
In an electric toothbrush primary AA cells last up to 3 weeks but lose power after about 2 weeks so the torque drops and the head will stall if there's much resistance. The Eneloop & Fujitsu Pros last a month easily. I swap them every month to avoid going too low.
I'm not sure a single cell would work with anything but newly formed whiskers. I used to charge up a really big capacitor (5-10000 uF) to around 20 volts and zap the whiskers with that. Once started, The whiskers tend to re-form but if the cell is kept charged it will usually auto-zap.
As will the charge rate (rather than charge level), something where most people thing bigger / quicker is better. ;-(
I specifically buy chargers where the rates are either 'mild' (where the cells don't heat noticeably whilst charging) or are charge current limited / adjustable (and I can ensure the above).
When racing RC cars in the very early days, the (Nicad) cells were built into the vehicle and so were raced and re-charged nearly continuously thought the session.
When we moved over into removable packs, they were often fan cooled after use and during recharging, to try to minimise damage.
I believe in the case of some chemistries, the rate of charge can impact the charge density. A slow charge can form fine crystal structure and therefore a greater energy density but a smaller surface area and so a slightly lower discharge rate.
Talking to a wedding photographer a few years ago he used the highest capacity NiCads he could find but would cane them re recharge rate, killing them a short period. However, he accepted this 'cost' as part of his overheads because he often had little time between shoots to get the batteries recharged again.
Cheers, T i m
Give us a clue, what kind were they? Rechargeable Ni Cads do not like being left Nickel metal hydrides can be better, but the really ones did seem to suffer this way as well as they self discharged Rechargeable Alkaline are meant to be only taken down to 70 percent then trickled back up again. The more exotic batteries normally need very careful handling to tread the line between exploding and not wearing out with too many cycles.
Brian
I never had any luck with nicad. The killer is if they are used in series as the one to go down first gets reverse charged by the others in use. Brian
In message snipped-for-privacy@4ax.com, Custos Custodum snipped-for-privacy@privacy.net writes
Don't know. Regular event with a nice portable Tektronix scope. Bench use, plugged in to supply. Lab rules were that the bench power be turned off at night!
By morning one or more cells would fail to take a charge.....
My Sony NiMH AA batteries, marked "CycleEnergy", bought 2008 are doing fine. They are mostly used in my Caplio GX8 camera that takes 2 AA batteries and have been recharged many times.
The Energiser NiMH AA rechargeables that were bought a few years later go flat much more quickly and one made the intelligent charger flag it as a bad cell, so that one has gone.
A good quality battery charger that doesn't overcharge is probably a good idea, also, while they might be convenient I suspect that 1 hour chargers shorten then lives of rechargeables.
I had the occasional cell that a 'smart' charger didn't like. Still around
1.15V, so not deeply discharged. 5 min. on a 'dumb' charger and it would then charge OK on the 'smart' one.
The Nicor defaults to 350mA on an AA; I set it to 150mA and let it have all the time it needs. Thanks to this group, I learnt thas rapid charging is bad.
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