Not used for three months

Audio2

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Apr 5, 2015
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We have not used our Woosh kits for three months because my wife had to have serious abdominal surgery. It is likely to be a further two months before she uses it again. The batteries are registering 39.4 volts today & do not appear to have lost any charge since last used. Is the lack of use going to have any significant impact on the batteries & should I be doing anything to maintain them other than monitoring the voltage.
 

flecc

Member
Oct 25, 2006
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30,598
We have not used our Woosh kits for three months because my wife had to have serious abdominal surgery. It is likely to be a further two months before she uses it again. The batteries are registering 39.4 volts today & do not appear to have lost any charge since last used. Is the lack of use going to have any significant impact on the batteries & should I be doing anything to maintain them other than monitoring the voltage.
I never leave any lithium batteries more than three months without some activity, so I'd recharge them both now as a precaution. They'll then be in good shape and ready for use in two months time.
.
 

Nealh

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Aug 7, 2014
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Tbh I would go the other way Flecc and fit them to the bike and either fire the bikes up on PAS or actually take the bike around the block once just to wake everything up. As long as voltage is at or above nominal I see no need to charge any more.
 

RobN

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May 15, 2020
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We left our bikes for about 5 or 6 months in the garage not used due to being fair weather riders (yep and no guilt, just honesty ) with no bad effect on the battery. Just put on charge before we used them again for a few hours.
Regards
Rob.
 

Nealh

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Aug 7, 2014
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At 39.4v I wouldn't charge higher as not be used but a 5 minute whip round the block is all that is needed for now.
 

Audio2

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Apr 5, 2015
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I have fully charged both batteries & will try to take each one for a short ride in the next couple of days. Thanks for your help.
 

Croxden

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Jan 26, 2013
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Just as a matter of interest, an Aldi garden tool battery ran its self down within three months and refused to charge. YouTube to the rescue, the charger it seems doesn't see enough voltage and thinks the battery is dead. All I had to do was put a bit of charge into the battery via another bit sticking wires like to like. After a while it charged.
Someone will explain I'm sure, but if this helps someone, good. All the other lithium batteries I have had over the years have always behaved. I think Aldi are going downmarket, they used to have good stuff.
 

flecc

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Oct 25, 2006
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Tbh I would go the other way Flecc and fit them to the bike and either fire the bikes up on PAS or actually take the bike around the block once just to wake everything up. As long as voltage is at or above nominal I see no need to charge any more.
Ideally yes, but I still wouldn't leave them uncharged for five months as was going to be possible. We've seen so many cases of batteries registering nominal voltage ok but that collapsing under load.

I've reached the conclusion that there's too much fretting about fully charging. I've never heard of any case of that harming a lithium battery, indeed in the e-car world topping up to full every time is the norm with those batteries commonly lasting ten years.

And for each of we enthusiasts in here I'm sure there several e-bikers outside who are innocently topping up their batteries in the same way with no problems.
.
 
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GSV3MiaC

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Jun 6, 2020
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If the battery gets flat enough, the bms system may not have enough power to start up, which is tricky. But for most of the batteries I have played with we are talking years before the self discharge gets them to that state, if they start from full.

Bms seem to default to fail safe, which I guess is reasonable, given the possible failure modes.

If there is some ongoing current draw, like those devices running internal clocks, or laptops listening for wake on lan, the battery can get itself into unusable state in a few weeks or months, but i dont think bike batteries do that.
 

flecc

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Oct 25, 2006
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If there is some ongoing current draw, like those devices running internal clocks, or laptops listening for wake on lan, the battery can get itself into unusable state in a few weeks or months, but i dont think bike batteries do that.
The BMS can do that. Only the few e-bike batteries that have a sleep mode avoid that by shutting down the BMS after a week or two.
.
 

mike killay

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Feb 17, 2011
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Over the past 10 years I have always kept my batteries fully charged.
Is the old advice re 80% for storage still, true?