STATUS of ESS/Storage Cells being purchased. (commodity cells)


Offgrid Cabineer, N.E. Ontario, Canada
I figured I would chime in again here, with some personal oberservations from my Thrash tests related to the popular EVE 280 Cells people are getting. Below is the chart that explains it best from their docs. The curve is consistently from about 3.35-3.37 volts post charging & settling to 3.10 volts, by the time the cells reach 3.00 that's pretty much it.

A Tip:
Also by 3.10V when a load like a Fridge Compressor kicks on, that surge will drop any Lazy cells possibly to cutoff if heavy enough. HENCE I Strongly Suggest that increasing Low Volt Disconnect Delay Time on your BMS to allow for a surge pull when at lower voltage, this applies to your Inverter if it has a setting for low volt delay. Start with 10 Seconds, no more than 15 Sec, lest other issues (unpleasant ones) occur.

There is much Ado about getting to 3.65 or even 3.50 but really, the curve for these cells from my own oberservbations simply says there is no point. In addition, if you are knocking off 5% from the Top & Bottom anyway, that gives you 252AH available, well there abouts. From what folks report here as well, this bears out better actually, overall, sure there are a few anomolous cells, they are the exception, rather than the rule.

I feel that the general "Commodity" cells or whatever people want to call them, do live up to their basic specs, sure you may get a dud in a batch that is either a Runner or Lazy. Get an extra cell or two or enough to make a 12V battery (there's always use for a 12V battery somewhere) which can use the oddballs that will limit the pack.