Hi, I'm new to the forum. I have been finding it an excellent source of information, especially about home built batteries and Goodwe inverters. I have recently had a problem, so it is my turn to ask for some help (I have searched a lot looking for answers to this already). For what it is worth I am in Perth, Western Australia.
I have a Goodwe 5048 ES (Firmware version on the inverter is 122214/2222E) and 6.6 kW of PV and a home-built battery. My battery is made up from cells that I took out of an electric car I built in 2010 when I recently replaced the pack. The cells are Winston 160Ah LiFePO4, configured in 16S3P (i.e. 56V) but given the degradation of 12 years in the car I have been assuming the 3 x 160 Ahr in 3P parallel are good for 280 AHr and overall the pack is good for around 14 kWh.
For a BMS I am using a system that was made here in Perth (Australia) by ZEVA (unfortunately they are not made any more) https://www.zeva.com.au/index.php?product=140. Functionality includes balancing, monitoring each cell voltage (high/low), overall high/low voltage protection, high/low current protection and SOC etc. This BMS controls its own contactor so can isolate/protect the battery if need be. The BMS used the BYD protocol to talk to the inverter via CAN bus and set the SOC, set voltage, charge rate etc.
I first installed the battery over a year ago (June 2022), and the whole system worked fine. It ran this way for around 12 months. Unfortunately when I recently had some electrical work around the house, somehow when the electrician isolated the house (and battery) something went wrong and now the inverter is throwing up a "Battery Communication Failure" for the BMS status (note all he did was throw the breaker to the battery so no idea how it created a problem). So I have been running the battery as a self-defined battery since with no BMS connection.
I recently had to do some mods to my BMS, and so took the battery off-line. The trouble is when I reactivated it, the inverter listed its SOC as 10% even though it was nearly full.
So I am trying to work out how to get the inverter to reset the SOC. The key self-define battery settings that I am using for the PVMaster app basic settings are:
Australia A
General mode
Self-Define battery
Battery capacity 280 AHr
Charge voltage 56V
Current 90.2A
Discharge current 100A
SOC protection on
DOD on-grid 90%
DOD backup 90%
Float voltage 54V
Float current 5A
Float time 30min
Then next, exit and the inverter does a re-start
From what I have read the inverter should then charge up to the charge voltage (always seems to get to 55.7V but not 60?) then go into float and after 15 min set the SOC to 95%, but it is not doing that for some reason. Even after a few hours at full voltage and with the house exporting >1kW, it still did not reset the SOC. So I have a full battery with an inverter that thinks it is at 10% SOC so is not using its capacity.
Other things I have tried:
With the battery charged at 56V, set the battery voltage in PV Master to 57V, then once it charges to 57V reset the voltage to 56V (so the battery was over the "full" setpoint as it was >56V)
Isolating the battery, telling PVMaster there is no battery, rebooting, then once the system is up and running again going back in and adding the self-define battery, but again it comes in at 10% so is not seeing that the voltage is at setpoint so it is full
Can anyone advise how you should reset the SOC, if I am using any wrong settings etc, or if there is a way to force the inverter to reset the SOC to 100%?