Help Needed with LiFePo system

[Off Grid Caribe]

I have a 24 V 300 ah off grid solar system that is made up of 6 12 V 100 ah battleborne batteries. Its in series and parallel The system shut down last night. It was at 26.4 at 8 pm. One ceiling fan a fridge and an internet router was all that was drawing power. When I checked the system after it powered off and I turned off the inverter switch and charge controller switches the left Bank of batteries reads -8 V the right bank reads 12.73 V with the total array reading 4.5v when connected to the inverter. when I disconnect the ground cable so that I’m no longer connected to the inverter the left Bank reads 10.5 V and the right bank read 12.7 V. And the whole array reads 23.2 V. Does this signify that the inverter is bad or could this be a battery problem? We have flexmax outback controllers and an outback inverter. Thank you for any insights and guidance!

 

[timselectric]

Sounds like one of the batteries hit low voltage cutoff.
This is common for batteries in series to drift away from each other. Check each battery to find the culprit. If this is the case. You will need to disconnect the batteries and charge all of them to full.
If you don't have any other issues. Then you can hook it all back up.
This will be part of regular maintenance. With BMS controlled batteries in series.

 

[BentleyJ]

when I disconnect the ground cable so that I’m no longer connected to the inverter the left Bank reads 10.5 V and the right bank read 12.7 V. And the whole array reads 23.2 V. Does this signify that the inverter is bad or could this be a battery problem? We have flexmax outback controllers and an outback inverter. Thank you for any insights and guidance!

Could you please clarify the following:
1) Is this a mobile system or stationary, Battleborn is more common in RV's and such.
2) When referring to "ground" this is the Negative lead from the battery connecting to the inverter not "earth ground".
3) So its a 3P2S configuration.

10.5V = 2.625V per cell. At that level the BMS is probably disconnecting as soon as a load is put on it which would explain why the voltage is different in the connected vs. disconnected state.

23.2V = 2.9V average per cell.

So your batteries are completely discharged and out of balance as well
They should be disconnected and individually charged with a suitable 12V charger.

 

[Off Grid Caribe]

Yes, disconnecting the ground is the ground from the inverter and the batteries were just recently charged up completely and they maintained a stable rate disconnected from house power for over a week just connected to the solar panels with the house power disconnected while I was out of town my landlord had everything connected up and the batteries stayed at a good level for a week until when I returned home. The first day it was at 26.6 in the evening and I woke up to 26.2. The next day was a little cloudy, but at the end of the day it was at 26.4, and in the middle of the night around 4 AM the whole system shut down.

 

[Off Grid Caribe]

I should clarify they were individually charged up to 13.7 V each and held there so they would balance, each one, one by one and then the entire system was connected back together and hooked up to the solar system and it stayed that way for a week without house power.

 

[Off Grid Caribe]

Sorry it is a 3s2p system and it is stationary in an offgrid home with no electricity on this island

 

[Off Grid Caribe]

Sorry it is a 3s2p system and it is stationary in an offgrid home with no electricity on this island

Sorry its 3 in parallel and those banks are in series to make a 24v 300 ah system

 

[MisterSandals]

Sorry its 3 in parallel and those banks are in series to make a 24v 300 ah system

Are these wired in a balanced manner? Can you post a pic, sketch or description?
It’s usually not obvious what is good vs bad and often can be improved with little effort.

 

[JunglePower]

Are these wired in a balanced manner? Can you post a pic, sketch or description?
It’s usually not obvious what is good vs bad and often can be improved with little effort.

 

[Off Grid Caribe]

Yep this is it ^ thats my landlord I believe. We are working through it

 

[timselectric]

That's 2s3p.