Ya, that’s the plan. Will cycle the battery a few more times and keep an eye on things. If I notice irregular discharge patterns and/or the strange charging behaviour continues, will remove that group and test all the cells for IR and capacity to see what’s up. Might just drop 4 new cells in There bc it might not be worth the headache for $20.
Edit: nvm. 4 new cells will cost me $100 w shipping and all the other bullshit. I have 2 extras. I’ll figure out which cell is the problem and replace it. Fucking PITA as I just got this board ip and running and tuned just perfect.
Looking forward to picking one of these kits up to get my feet wet in the battery game. Been reading as much as I can but it’s just one of those things you need to do.
10 across is doable and your right it would take up every nook and cranny in the Pelicase 1200. The only challenge with this build would be getting the power leads out neatly and charger port placement/loop key.
What I love is that the BMS leads all keep to one side. OK, I’ve taken a deep breath and I’m ready. If it goes ahead I’ll drop the build pics here.
PSA: dont leave your maltrics pluggedin into a car battery while the battery is charging unless you know what youre doing. Aparently some chargers create voltage spikes that can fry the welder’s on board microprocessor. Ask me how i know
You’re 100% correct, a small part of me wants to accept the challenge although I don’t think it’s worth my sanity. I have little of it left as it is. It’s good to see some of these build pics though as inspiration. @TheRef It never crossed my mind to lay the cells out that way for the entire battery build and boy, you sure did make use of the 5mm gap for all your cable routing.
yup cartianly not a monetary travesty. I already ordered a new nano . was like$20. It just sucks because i had just finished all my test welds and sat down with my glued up p groups to start on my first ever pack and then discovered it had passed away. lol
I’ve been testing some cells from a recent battery build where I had multiple P groups misbehaving. The cells used came in two different batches. Pack is a 12S6P.
I ripped out the P group then charged / discharged 2 cells, everything seems ok. What I did pick up on was a huge difference in resistance. The 2K509 cells measured at 44mO while the other at 28mO.
The pack was built using 20 of the 2K509 cells.
Dr google tells me the higher the number the worse the cell is.
What I’d like to understand is do folks build batteries using cells from different batches / build dates?
Also is measuring the cells resistance a reliable way to test an individuals cells capability?
How many cycles on the pack? That’s quite a voltage disparity. IR can definitely give some clues as to the state of a given cell. It can hint at damage to the cell or an aging/faulty cell. Did u get these cells from an authorized distributor?
I also think behaviour during charge/discharge is also helpful. If a group is charging/discharging faster than other groups this is indicative of a capacity disparity. This could be from one or more cells operating w reduced capacity, or a broken weld or a faulty cell in th group.
FYI, the IR for both of the cells u tested is out of spec. IR for p42a’s is speced at 13.8 Mohms.
I only post this so others can learn from my mistakes.
