Anyone had trouble with 12v battery at Positive end draining?

[zack6736]

I have four 12v Rich solar batteries (LFePO) in series making a 48 volt battery for my LV6548. Last two mornings I go out and there is a fault and batteries are not charging and shows they are empty. Each battery checks out just a bit over 12v EXCEPT the last one that the positive terminal connects to and it registered at 3v. After putting a charger on the one low battery for a minute, the inverter starts charging the batteries once again and it's good to go as far as charging back up. Is this indicative that the battery is bad?
Thanks,
zack

 

[sunshine_eggo]

I have four 12v Rich solar batteries (LFePO) in series making a 48 volt battery for my LV6548. Last two mornings I go out and there is a fault and batteries are not charging and shows they are empty. Each battery checks out just a bit over 12v EXCEPT the last one that the positive terminal connects to and it registered at 3v. After putting a charger on the one low battery for a minute, the inverter starts charging the batteries once again and it's good to go as far as charging back up. Is this indicative that the battery is bad?
Thanks,
zack

LFP sitting at just a bit over 12V are effectively empty. You just have one 12V that has a little less capacity than the others, and the BMS is in protection mode reading an artificially low voltage. Charging it individually is "waking" the BMS back up and allowing normal function.

You are using too much of your battery capacity, and/or you have insufficient solar for your loads.

Recommend you increase the inverter cut off voltage to a level where BMS protection is not triggered. I'd personally start around 48.8V (12.2V/12V).

VERY important that all your 12V are reading the same voltage especially when system is at peak voltage (57.6V recommended).

 

[timselectric]

Your batteries are out of balance. This is common when you put BMS controlled batteries in series.
Separate the batteries and fully charge them individually. Then charge them in parallel for a few hours to balance them. After that, you can put them back in service. This will have to be repeated from time to time.
This is why I never recommend putting BMS controlled batteries in series.

 

[zack6736]

Thank you both. Will charge individually and then in series and check the cuttoff setting and change it. This was my first system, and it's for the koipond power. I have 12-200 watt Rich Solar panels and my power consumption runs about 800 watts except at night when the waterfall shuts down and then it's about 450. The system that powers the house is a 15K Sol-Ark and SOK smart batteries and this system ROCKS!!! If I didn't have so much invested in the 12v Rich Solar batteries I'd just tie the koipond into the Sol-Ark.
zack

 

[GSXR1000]

no matter how balanced your 4 batteries are when you run them dead like that one will Always turn off first (the 3 volt thing)