Charging problems

[Nealh]

Like d8veh I was only thinking of 18650/cylindrical cells,pouch polymer cells are different. I don't think you are seeing anything unusual except maybe consider they are past their best and time to use a cylindrical celled battery with high spec cells.

 

[Nealh]

From my experience pouch cells act differently and IR tends set in quicker then cylindrical cells affecting voltage sag and unbalanced cells, pouch packs can be less predictable.

Any puffed cells will be an indication of a pouch going bad with a IR higher then others.

Each string has 3 pouches so only needs one pouch in a few strings to be a bit puffier then the others to cause your issues.

 

[Wilkco]

Possibly one cell a little puffed up at no.7?
I’m not sure.
Can I not just remove the cells

 

[anotherkiwi]

Possibly one cell a little puffed up at no.7?
I’m not sure.
Can I not just remove the cells

Bingo! Not good... Best to bin the battery and start over as suggested above.

 

[Wilkco]

Ok thanks for all your help,looks like it’s a new battery then.

 

[Nealh]

Possibly one cell a little puffed up at no.7?
I’m not sure.
Can I not just remove the cells

Each pouch is/was 5ah, so 3 pouchs in each string is 15ah. Removing one won't help it will make things worse.
Pouch cells tend to have a higher lvc then cylindrical as pouch chemistry is a bit more volatile if mistreated. Pouch cell voltage crashes very quickly below 3.5v, and within approx. 50m of riding distance a cell at 3.5v can easily be at < 3v in the few seconds it can take to travel that distance.

 

[Nealh]

Ok thanks for all your help,looks like it’s a new battery then.

For your set up look for a good spec cell like Sanyo GA ( Aka Panasonic), Samsung 30Q, LGHG2 or MJ1.

One option to consider;
30Q pack.
http://enerprof.de/shop/batteries/ebike-and-pedelec-batteries/enerpower-softpack-48v-13s6p-18ah-with-bms-40a-pedelec-battery-10x8-diy/