I acquired two "new," old stock GBS LFP 200Ah 12v packs (GBS LFP200Ah-A cells) primarily to learn and experiment with. They'd been sitting in their boxes in a pole barn in Michigan for an unknown duration, but perhaps 3-5 years. Pack voltages were around 13.14v when I opened them. I added a JK-B1A8S20P BMS to each battery, charged them, noted some drift in the cell voltages and so top balanced the cells in each pack. Both packs are yielding about 75%-80% of their rated capacity. As voltage drops, I have one battery with three cells that range together with one outlier that maintains higher voltage (vdiff= .366 near UVP disconnect); on the other pack, I have one cell that drops voltage faster than the other three (vdiff=.1 near UVP disconnect). No temperature or other anomalies during charge or discharge.
Both battery packs show swelling, primarily on the end nearest the POS (+) terminal. Swelling was present when I got the batteries, so it is not related to my charge/discharge (I charge to 14.1 with a Victron charger - no float - and a tailcurrent setting of 7.5A). Again, the batteries came to me unopened and unused, so - apparently - no prior history of overcharging. As I said, I acquired these cells to learn and experiment with, but my question is this: should I be concerned about the safety of the cells due to the swelling? I did do some reading on here regarding EVE cells and bulging, and it seems it's never good but not always dangerous. Anyway, curious to know what those more experienced than I think. I am attaching images for reference. Images show swelling and gaps between cells due to swelling. I appreciate your informed input. Thank you.
Both battery packs show swelling, primarily on the end nearest the POS (+) terminal. Swelling was present when I got the batteries, so it is not related to my charge/discharge (I charge to 14.1 with a Victron charger - no float - and a tailcurrent setting of 7.5A). Again, the batteries came to me unopened and unused, so - apparently - no prior history of overcharging. As I said, I acquired these cells to learn and experiment with, but my question is this: should I be concerned about the safety of the cells due to the swelling? I did do some reading on here regarding EVE cells and bulging, and it seems it's never good but not always dangerous. Anyway, curious to know what those more experienced than I think. I am attaching images for reference. Images show swelling and gaps between cells due to swelling. I appreciate your informed input. Thank you.
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