I have harvested my first 50 cells or so, and I have some questions.
First, I pulled apart a battery bank, it had already had the front, and back panels, and BMS removed, it was basically a 3S4P cell pack in an aluminum case with all cells at 2.62V. If I didnt know any better I would say somebody tried to harvest it and couldnt figure out how to get the cells out. I ran a knife between the cell wrapping and the case to break the glue, and pushed the cells out. I took one 4P pack apart and tested the cells, all 4 were perfect with 100% capacity and .04V self-discharge after a week. I charged the other two 4P packs for testing while still assembled. The packs have no self-discharge issues; they test the same as the individual cells. So, the question is should I take the other 2 packs apart, or do capacity testing as a 4P pack? I dont have a spot welder, and removing the strips just to replace them with solder seems to invite trouble. Ive read here before of others leaving parallel packs intact if they pass self-discharge testing, and Im curious about the groups experience with this is.
Second, Im curious as to whether there is benefit to disassembling the pack ASAP. I have noticed people with hundreds of cells, removed from packs and awaiting testing.
Third, when you go to pick up packs from the recycler, and he drops a 55Gal drum of misc. packs in front of you, how do you pick which packs are worth the effort to harvest and test? My first check is to look at SOC meter if it has one, if it still responds, it goes in my harvest bin. Next I look for dates that would give me a rough age, but beyond that it is kind of hard to tell what to pick.
Thanks again for your help.
First, I pulled apart a battery bank, it had already had the front, and back panels, and BMS removed, it was basically a 3S4P cell pack in an aluminum case with all cells at 2.62V. If I didnt know any better I would say somebody tried to harvest it and couldnt figure out how to get the cells out. I ran a knife between the cell wrapping and the case to break the glue, and pushed the cells out. I took one 4P pack apart and tested the cells, all 4 were perfect with 100% capacity and .04V self-discharge after a week. I charged the other two 4P packs for testing while still assembled. The packs have no self-discharge issues; they test the same as the individual cells. So, the question is should I take the other 2 packs apart, or do capacity testing as a 4P pack? I dont have a spot welder, and removing the strips just to replace them with solder seems to invite trouble. Ive read here before of others leaving parallel packs intact if they pass self-discharge testing, and Im curious about the groups experience with this is.
Second, Im curious as to whether there is benefit to disassembling the pack ASAP. I have noticed people with hundreds of cells, removed from packs and awaiting testing.
Third, when you go to pick up packs from the recycler, and he drops a 55Gal drum of misc. packs in front of you, how do you pick which packs are worth the effort to harvest and test? My first check is to look at SOC meter if it has one, if it still responds, it goes in my harvest bin. Next I look for dates that would give me a rough age, but beyond that it is kind of hard to tell what to pick.
Thanks again for your help.