Solarismaximus
New Member
Hey guys I've had my system fully setup and running since July. Drop in lifepo4 batteries, different makes but bought around the same time. All have tested roughly same ah give or take 1 ah difference. Inverter only pulls 24 amps at most. Running 24v series parallel, I have one series string of 12v 60ah, and two of 12v 100ah. Everything was properly balanced before connecting. ALL connections and cables are same length between batteries and all batteries are connected to bus bars. Cables from bus bars to inverter and scc busbar are equal as well. Using 4 guage and cold crimped. I have slight ocd so everything is exact as far a connections and distribution go. Pos and neg leads from bus bars are on opposite ends with shunt battery monitor. I regularly check voltages and maintain my system just bc I enjoy it. Voltages have been balanced since I set it up. Just recently we had a entire week of no sun or very inconsistent sun and my bank was depleted to around 20% where it sat like that untill a day ago. Finally got a full day of sun and got the bank up to 90%. Came home after work and found it had depleted down to 22% but had tripped the low voltage which is normally about 20%. checked the voltages and found that the 60ah string which is located at the "top" of the system (closest to postive lead out from bus bar) and the middle string, had both batteries, at the beginning on the string (closest to pos bus bar) were almost 1 whole volt apart 11.7 for both batteries at begging of strings and 12.7 for batteries at end. Both strings equally unbalanced. While the bottom string was still perfectly balanced at 12.2. Turned inverter completely off last night so i could start getting batteries fully charged up. So as of right now I am at 40% accoring to battery meter 26.68v. Top string is 13.23 and 13.34, middle string is 13.20 and 13.38, and bottom string is balanced at 13.28. So now only .1 to .18 voltage difference. So confused rn lol.Not really sure what happened here as it's been running fine, ah usage is going up and down and measuring the same across inverter, scc, and meter. I've tried to look up everything I could online about this but couldn't get a definitive answer. Is this ohms law lol? Do I need to use a balanacer as I have 3 different brands of batteries? Had this set up according to wills video where he shows his full battery bank setup with mixed brand and ah in parallel and thought I understood everything but idk. I also know having these wired different on to the bus bar might make a difference but I digress..... Idk would like any advice plz and thx! I'll post once batteries are fully charged according to meter or if they even get to that without one of the bmss turning off bc of over charge.
