Hybrid system shutdown

My hybrid system has two Growatt SPF 3000TL-LMV-24P 24V 6kW Split Phase 120V/240V inverters with two EG4-LifePower4 24V 200AH Batteries.

The system had been working well for several months with no problems. A few days ago overnight it stopped working. I had It set to SBU and we weren't getting much solar input. It had been switching to utility whenever it went down to the set percentage but this time it did not go to utility and it ran the batteries flat. This cut power to my sub panel and the essential loads that were on it. I recharged the batteries, checked all the settings, none of them had changed. It seems to be working fine now. There were no storms, nothing unusual happened, no breakers were tripped. I'm trying to figure out what happened and how I can prevent it from happening again so I can trust this system. I'm hoping you have some helpful input for me. Thanks!

What's the low voltage cutoff set to on the inverters? Is that what you mean by 'it stopped working'?

Samsonite801 said:

What's the low voltage cutoff set to on the inverters? Is that what you mean by 'it stopped working'?

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Low voltage cutout is and has been 21%. The batteries were drained to near zero, it did not connect to utility, and so all output stopped, the inverters shut down. BMS would never initiate a bottom balancing, would it? It's been working properly since and all I did was charge the batteries and start the inverters again, checked all settings, none had changed. Thanks.

sundug said:

Low voltage cutout is and has been 21%. The batteries were drained to near zero, it did not connect to utility, and so all output stopped, the inverters shut down. BMS would never initiate a bottom balancing, would it? It's been working properly since and all I did was charge the batteries and start the inverters again, checked all settings, none had changed. Thanks.

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Perhaps something just hung in the firmware code while running on that iteration, assuming maybe you rebooted it and is working fine again? Maybe it lost its correct logic due to hung condition, just a theory I guess.