Hennie_Strydom

Does anyone know where I can get information about the serial communication with the BMS of this battery? Information like Baud rate, command and status format?

Thanks a lot.

Yes please send me the @Coulomb link.

I have an Axpert 5kva/4kw inverter that is behaving erratically. The inverter works fine when there is mains power and/or solar power. At night when load shedding starts, it works fine for like 45 minutes and then gets a fault code 03 (Battery voltage high) mostly. The battery voltage it reports is 19V (not high) and the measured voltage is 49V. I have to restart it by switching the battery on and of. Then it faults again after a few minutes often with the same code, but sometimes other codes. The measured values reported does not make sense. Can anybody recommend a good repair vender?

There is no BMS connection between the inverter and the battery - only the 48V terminals are connected.

The firmware is: Main CPU 72.70 Secondary CPU 4.12 I can see now that the problems only start when the system has been running on the battery alone with no solar or mains. The behavior is quite erratic. It sometimes messages mains power down, when it is not or even over current fault when the load is just 70W. It seems as if the measuring system is faulty in this mode.

Thanks so much for the information. Do you think it might also help to upgrade the firmware? The inverter also sometimes does a power glitch for about a second. During the day it often shuts down the solar input and if I do not tweak it, it remains off for the entire day. I fix this with a workaround using a raspberry Pi via the serial port of the inverter. I give a command to bump the battery CV voltage up 100 millivolts and then 1 second later bringing it down again. This has been working well for 3 years, but I believe it is a firmware bug.

My Axpert 5kva/4kw started behaving erratically. I have had it for more than 3 years. It shuts down with fault 03 - Battery Voltage too high, but the voltage displayed is 19V while the actual voltage is 49V. This only happens when the main power is down at night with no solar input. It it sometimes recovers, but I also have to restart it by hand. During the day with normal solar input and mains it works perfectly. Any ideas? The battery is a LiFePO4 and is also more than 3 years old. The capacity is probably down to 50%, but I have not checked that.