Hi my diy lfp battery shut off my inverter after about 3/4 hours on full charged battery. 280ah cells. On looking at the app the first cell was well below the others. I charged up the battery today via solar and the first cell I think it’s the one with the positive output. But could be the one connected to the dalie BMS 4s. Is this normal or do I have a weak cell? Thanks
LFP first cell voltage drop.
- Thread starter jonp
- Start date
Q-Dog
¯\_(ツ)_/¯
Bad cell? maybe. Or bad connection, or bad BMS. We can guess. Or, do you have a meter to do some checks?
A volt meter?
Q-Dog
¯\_(ツ)_/¯
That is more typical of a poor connection. Check all lugs, bus barsand BMS sense wires.
Yes I hope that’s correct I tightened the negative seems better. Will go through them all later. Thanks
Horsefly
Solar Wizard
Not to disparage the capacitor-based Hultec balancer too much, but I had one of those exact balancers - but 24V 8S in my case - go bad. It pulled one of the cells way down in voltage in a relatively short amount of time. The balancer board was very hot. I pulled it off and no longer use any of them. The JK BMS is what I have on all three of my 24V packs, and it does a fine job keeping the cells balanced.
I never left my haltec balancer on for more that 30-45 min and only when cells were above 3.4v.
I left it connected just wired in a switch to the haltech and it was off 95% of the time.
Sure it took some effort to monitor but in 30 min the unit brought my cell delta from .050 down to .005. It’s crazy how it fast it works when the cell delta is its highest at the top of the charge.
I left it connected just wired in a switch to the haltech and it was off 95% of the time.
Sure it took some effort to monitor but in 30 min the unit brought my cell delta from .050 down to .005. It’s crazy how it fast it works when the cell delta is its highest at the top of the charge.
Have one of those, I just use the JK Inverter BMS dry contact to turn the Heltec active balancer on at pack (16 cells) voltage 55v and stop at 54v since I can't enter decimal value in the app.
Granted that JK has 2A active balancer, but it doesn't hurt to add extra?
Horsefly
Solar Wizard
Unless it goes crazy like mine did, and then it definitely does hurt.
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Let hope it doesn't go crazy?
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