Cell Strain Characteristics With Making Series Connections

[adrock8519]

Hi

Am I correct in noticing that the group of cells in the last series connection of a lipo pack always seem to take the most strain and develop cell sag before the others cells?

Also how far can you go with making series connections. For example does a 24s pack put more individual strain on the cells than say a 12s drawing the same amperage? Do the cells towards the end of a line of series connections take more strain than those at the start of the pack?

thanks,
adam

 

[amberwolf]

I don't know for sure, but I think it's not really that the cells are at the end of a series setup, but rather that they are on the least-compressed part/end of a pack. So they can swell more easily, and develop problems since their outer edges are compressed but the center is not, at least with the pouch type RC LiPo stuff.

You might not see any visible swelling, but I think there are still patches of insufficiently-compressed area in the pouches on the end(s) and that this is what causes the problems in those cells.

I don't know if anyone has determined conclusively what causes it, though.

 

[adrock8519]

So The batteries are best to be kept tighter? I always though it was best to give them some space to expand a bit

 

[Ypedal]

Half way down :
http://ypedal.com/Chaos/Chaos6.htm