4 405w panels vs 12 100w panels...


New Member
Feb 4, 2021
How cold was it overnight and during the day?

LFP should not be Charged at 32°F or lower But can be discharged in Much colder temps and just being in cold temps does not hurt them.

10V is totally empty for LFP and should trigger the BMS low voltage disconnect.
What voltage were your 100Ah Ampere time batteries when you received them?
Have you been discharging and using the batteries?
The weather had said 36 degrees but to me it felt much colder. That was nightime. Daytime was in the high 50s I would guess.

I dont know their initial voltage upon receipt. I dont have a voltomoter or I would have checked. The documentation stated they should be charged individually at first, then paralleled for 24 hours. I didnt know how I was going to charge them. I didnt have all my supplies in yet. Our other system had went down a few days prior to their arrival. I had been trying to hook up a cheap inverter to some small tool batteries but couldnt find the small alligator clamps I needed. So I was talked into hooking up to one of these batteries. Hooked onto it here or there. Then it beeped after a period of time...several days at least but I was only using sparingly. I knew it had the BMS for protection so I thought it was fine. Then I read about the constant self discharge and realized it wasnt. I finally have most my supplies. Just waiting on the 12a fuse to arrive still. I hooked up the charge controller to each battery for a reading. It came back 10, 11, 13, 13. I read they dont get damaged until 8 something. I set up my temporary charge station with the 3 panels paralleled.

After covering the panels to disconnect...the battery wouldnt read at all. It wouldnt even power the controller. So I charged all the others up to 13.3 because it seems like thats what my charge controller stops them at. Then I paralleled the dead one to a charged one for 18 hours approx. Hooked it up and they both read 12.7 after that. Charged them both back up. They seem to be fine. I hope I havent done permanent damage.

This is my plan. I changed the location to an interior of a large cabinet. I just want to verify the wiring looks good especially with respect to the 150a class t fuse to the inverter. I am pretty sure I undeestood it correctly this time. Can you please confirm this? Thanks!