i want to know if I can identify “rogue” cells in my dodgy solarstorm battery. I’ve unwrapped it and it looks to be wired up correctly (unlike some!) so it must be the quality of the cells that makes it a bit rubbish. Thing is, being the bodger I am, I don’t want to chuck it for the sake of maybe 1 or 2 cells. Is there a way I can test individual cells for capacitance/quality?

If you’re just trying to compare then run it down and check cell voltage when it’s discharged. Those with low voltage are your dodgy cells, it’s that simple. If they’re really dodgy they’ll drop to 0V whilst some of the other cells still have plenty of charge.

Chances are though that none of the cells are great and it’s worth replacing them all.