Battery won’t charge past 99% and won’t stop charging

StuckintheSpokes

Finding my (electric) wheels
Feb 5, 2019
12
0
#1
I left it on 99% for about 30 minutes and it wouldn’t stop charging. Do I need to keep an eye on the battery when charging it from now on?
 

russ18uk

Pedelecer
Sep 18, 2018
68
18
#2
Could be balancing. Leave it for a few hours.
 

russ18uk

Pedelecer
Sep 18, 2018
68
18
#4
Makes no difference. Balancing could takes hours or even a day or more if a cell has drifted.
 

StuckintheSpokes

Finding my (electric) wheels
Feb 5, 2019
12
0
#5
Well after an hour more on charge the battery managed to get to 100%. The next time I charged it, same problem. From now on I think as soon as it reaches 99% I’m going to unplug and get on the bike.
 

wheeliepete

Esteemed Pedelecer
Feb 28, 2016
1,127
136
55
Devon/Dorset
#6
99% is fine, you are not going to notice any difference in range, but it's prob. a good idea to leave to reach 100% every 5-6 charge cycles to prevent the battery going out of balance. Depending how old your battery is, it could be a sign the cells are beginning to lose capacity. You see the same thing happen to laptop batteries.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
6,613
274
55
West Sx RH
#7
At 99% battery is balanced, likely only time imbalance will occur is if you only charge to 80/90% then the BMS will not even think about it or a BMS bleed resistor fails.
 

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