Off grid with 8 x Pylontech US5000 batteries connected to our Cerbo GX through the BMS.CAN. Haven't had any issues in the months since we set it up until today.
Today a couple of strange things happened. Battery temps were between 40-50F or so. Light loads. While monitoring the Victron MPPT charging the bank, when the bank got up to about 96% SOC it disappeared from the Venus.local display. But then it came back soon after and had jumped to 98% SOC. No errors. In the logs, I see:
It shows a blank line at 16:05:16 where it seems the battery stopped communicating with the Victron system.
But then it came back and showed it was charged to 100% and I stopped watching the console at that point.
But maybe ten or fifteen minutes later, the power went out in on our cabin. So we tromped through the snow the 700 feet or so to the solar shed where the equipment resides. The batteries all looked normal, no flashing error lights, but the Cerbo was beeping and the Quattro had a red light showing for "low battery." Which was odd given the batteries were fully charged.
So I turned the Quattro off and back on, and all the power came back on and it was inverting and supplying power again. But the Pylontech batteries were no longer detected in the system and the MPPT also threw an error 67 for "No BMS Detected" which makes sense since it appears the Pylontech batteries are no longer communicating through the BMS.CAN for whatever reason. They're now supplying power to the Quattro and we have power, but we can't monitor them. I haven't messed with any cables and I'm not sure why this happened. I tried unplugging the BMS.CAN cable from the Cerbo to the batteries and plugging it back in but that didn't fix anything. I turned the batteries off and turned them back on, still they no longer communicate with the Victron system.
Logs show that right around 17:03 the batteries stopped communicating and no battery info was logged after that.
Before this occurred, battery SOC and health was 100%.
No idea what happened. For now I have the MPPT off and we're basically just running power with dumb batteries. In the morning if the batteries are still unreachable through the BMS.CAN I might try swapping master batteries (changing which battery connects to the Cerbo through the BMS.CAN) to see if that does anything. If it doesn't, I guess I"ll shut our system down and contact Pylontech to figure out what we need to do. I can't charge the batteries if they don't communicate to the system because that would risk over voltage or over current.
Any ideas what might have occurred or how to fix this?
