Help from experts please

Wren

Wren

New member
Like many people now I have several cordless devices (drill, screwdriver, strimmer, vacuum cleaner) using lithium Ion batteries, from 18 to 25v.  After use should I recharge them and store fully charged, or fully discharge them and store discharged? Or is it ok to leave them partially charged and charge them again before use? Simple answers appreciated. Thanks
 
royfellows

royfellows

Well-known member
RTFM
(Read the F... manual)

Somewhere hidden deep amongst the silly health and Safety - goodbye common sense crap in ten different languages you will find a small paragraph in English explaining about storage etc. I have every confidence.

Lithium Ion batteries generally are best stored for long periods at 40% of the total charge. They do not fully discharge and if this was done would be scrap. The issue is discharging them down to cut off level and then storing whereby the charge could fall further harming the cells.
 
RobinGriffiths

RobinGriffiths

Well-known member
I have had a B&D 36V Lion strimmer for about 2 years now. I've always fully charged after use. It gets used twice every 3 weeks April to September, and gets stored fully charged over winter. And so far, no discernable drop in capacity.

Robin
 
Laurie

Laurie

Active member
All of my Makita 18v batteries are stored in 'as last used' condition except if they are flat.
After many years they all work perfectly.
 
Wren

Wren

New member
Many thanks for the comments.  As royfellows suggested I have RE-READ my manuals.  Unfortunately, none, for lithium or nickel batteries,, appear to have any advice on either long or short term storage! Plenty on overheating and not pouring flammable liquids over them? But nothing of any real use!
So thanks again for your helpful advice, as always. Wren
 
Bob Mehew

Bob Mehew

Well-known member
My understanding is as follows: NiCd cells have a memory effect which meant when left partially charged, the battery felt it could not take any more charge.  NiMH cells and Li cells don't like being taken to flat - they can give up working though they do have circuits to stop this.  But this can happen with self discharge if the time between use is long enough.  So I would suggest recharge after use and before putting into store, plus recharge before subsequent use or if left for many months.
 
NewStuff

NewStuff

New member
Most lithium cells have a faster self-discharge rate if stored full or nearly full, hence it's is recommended to store them at 40%-ish.

I haven't got the relevant whitepaper to hand, but I daresay I can dig out a link if you're really bored and want to be even more bored by battery curves.
 
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