Hi everyone,
I’m looking for technical assistance with a FoxESS system at a customer’s property in Lauderdale, Tasmania, Australia. We’ve been experiencing ongoing battery charging issues, and the customer has now reported that one of the inverters is repeatedly restarting.
System details:
2 × FoxESS H1-5.0-E-G2 hybrid inverters
2 × EP11 batteries
Reported BMS firmware: 1.013
Issue 1 – Battery not charging properly
The customer initially reported that one battery stopped functioning properly after a firmware update. A mismatch between the BMS firmware versions was identified, and we were advised to update both batteries. Both batteries have since been updated to the latest firmware, but the issue has persisted.
The affected battery has been observed remaining at approximately 48% SOC and charging at only around 14 W, despite grid charging being enabled and the charge power being set to 6000 W. Its SOC subsequently dropped to 17%, then 5%, and was last reported at 1%.
The monitoring portal has sometimes displayed the battery status as “Charging,” even though the actual charging power was negligible. We have also observed significant grid consumption during periods when the battery was expected to charge, without a corresponding increase in battery charging power.
Issue 2 – Inverter repeatedly restarting
On 24 September 2026, the customer reported that one of the inverters had been repeatedly restarting since approximately 5:30 AM.
The monitoring portal recorded the following events:
Code 21 – “The number of nodes in the parallel system is incorrect” on inverter 60LH5020394D056, occurring at 5:41 AM and 5:34 AM.
Code 194 – “Battery Voltage Fault” on inverter, recorded on 23 September at 10:35 PM.
Code 234 – “BMS Alarm” on inverter, recorded on 23 September at 6:17 PM and recovering on 24 September at 5:11 AM.
Code 28 – “10 Minute Average Grid Voltage Fault” was also previously recorded on the affected inverter on 8 September 2026.
System configuration
The monitoring portal shows both inverters under one plant, and the inverters have been shown in Single Mode. We were previously advised to separate the systems into two plants, but we would appreciate clarification on whether this is a portal-only requirement or whether there are concerns about the physical inverter configuration.
We also attempted to create a separate plant but were unable to do so, even using the old platform.
Assistance requested
What could cause the battery to discharge below its configured minimum SOC and fail to charge properly despite grid charging being enabled?
Could the BMS Alarm (Code 234) or Battery Voltage Fault (Code 194) be related to the charging issue?
What could cause the repeated Code 21 events and inverter restarts? Does this indicate a configuration or communication issue?
Is the intended arrangement of two independent H1-G2 inverters, with both EP11 batteries connected to one inverter, supported in Australia?
Does separating the systems into two plants change the monitoring arrangement, or are further configuration checks required?
What diagnostic checks would you recommend next, and should an onsite inspection be arranged?
We have been trying to resolve this issue for some time.
Thank you in advance for your assistance.
That's a fairly typical parallel system setup for here in the UK, I don't have specific experience of having to create seperate plants, @Will has parallel inverters and should be able to advise on that - but it seems sensible to have distinct plants.
Quite a few different faults being reported there, so start with the easier ones, either lift the 10 minute avg voltage limit a couple of volts, or disable that alarm.
The BMS alarm and battery voltage fault i've seen on new installs with older firmware, and checking latest firmware it is 1.013 - did both batteries definitely get updated ? - but to answer your question, for sure this error message would stop the battery from charging.
The code 21 is more of a worrying problem as that suggests some kind of configuration issue between the 2 inverters, there should be a parallel canbus cable between the 2 inverters parallel 1 & 2 and on the master the dip switch resistors should have been flipped - i've linked to Will's video where he runs through the setup of parallel inverters there may be something in there that can guide you, in case you've missed a step etc.. viewtopic.php?t=975
All that said I think being on-site will be the only way to resolve this, it's possible the 'faulty' inverter is charging it's battery but the datalogger comms is poor or not working, and being next to the inverter you can see real time what it is actually doing.
Quite a few different faults being reported there, so start with the easier ones, either lift the 10 minute avg voltage limit a couple of volts, or disable that alarm.
The BMS alarm and battery voltage fault i've seen on new installs with older firmware, and checking latest firmware it is 1.013 - did both batteries definitely get updated ? - but to answer your question, for sure this error message would stop the battery from charging.
The code 21 is more of a worrying problem as that suggests some kind of configuration issue between the 2 inverters, there should be a parallel canbus cable between the 2 inverters parallel 1 & 2 and on the master the dip switch resistors should have been flipped - i've linked to Will's video where he runs through the setup of parallel inverters there may be something in there that can guide you, in case you've missed a step etc.. viewtopic.php?t=975
All that said I think being on-site will be the only way to resolve this, it's possible the 'faulty' inverter is charging it's battery but the datalogger comms is poor or not working, and being next to the inverter you can see real time what it is actually doing.