Hi, my inverter shows ‘BMS Lost’ as an active error.
The app's showing as offline and we've had no data feed for 2 days with everything showing '0'.
The red warning light on the inverter itself is flashing red and the dongle is fast flashing red.
So far no luck with getting a solution from our installer.
I'm hoping this doesn't mean there's no PV production to the house or battery.
Any thoughts on how to resolve would be very welcome.
Thanks
Phil
Our set up:
Fox ESS H1-5.0 inverter
Fox ESS ECS4800-H3 (13.98 kWh total) battery
4.25 kW PV array
8kW Air source heat pump
"BMS Lost" means the inverter has lost comms with the battery management system.
Very likely you will be having no power generated by the system.
Check the BMS cable between the inverter and the battery for damage and that the connectors are seated correctly.
Check the battery status indicators then try a complete restart of the system
Shut-down
Start-up
Very likely you will be having no power generated by the system.
Check the BMS cable between the inverter and the battery for damage and that the connectors are seated correctly.
Check the battery status indicators then try a complete restart of the system
Shut-down
- Switch off the solar input (switch at bottom left of inverter)
Switch off AC input to inverter (red switch near inverter)
Switch off battery (switch off the DC breaker on the battery
Start-up
- Switch on PV input
Switch on AC input
Switch on battery DC breaker
Press battery Power button
Last edited by nrb501 on Fri Aug 07, 2026 11:20 am, edited 1 time in total.
H1-3.7-E-G2, 2xEP11-H and 6Kw solar
Manager(ARM):1.76
Master:1.57
BMS:1.012
Manager(ARM):1.76
Master:1.57
BMS:1.012
MANY thanks. Just tried this, but no change. None of the LED status indicators are lit up, if that's a clue?
Sounds as if the battery has powered off?, on the master make sure the DC switch on the battery is on, and then press the power button and shortly after the LED status light should come on.
As per Dave's reply that should start the battery.
Could you post a photo of the left hand side of the battery with the cover over the circuit breakers open.
I gave the wrong link for the battery manual, I've now corrected that (the control panel on the battery is the same though).
Could you post a photo of the left hand side of the battery with the cover over the circuit breakers open.
I gave the wrong link for the battery manual, I've now corrected that (the control panel on the battery is the same though).
H1-3.7-E-G2, 2xEP11-H and 6Kw solar
Manager(ARM):1.76
Master:1.57
BMS:1.012
Manager(ARM):1.76
Master:1.57
BMS:1.012
Thanks both, yes the battery had powered off - may have been me when doing the reset - the battery's installed with the panel about 2 inches from the wall so button not easy to access.
So the inverter seems happy with no red light or error showing but this doesn't explain why the error occurred before with apparently no generation since Tuesday.
The app still says zero generation though clear and sunny here - I've checked Fox cloud on the web and that says zero as well. Can't seem to connect to wifi - I've used Will's connect / reconnect video but keep getting a fail and can't work out why....
Let me know if you still need a photo - I can just about fit my phone down the gap
So the inverter seems happy with no red light or error showing but this doesn't explain why the error occurred before with apparently no generation since Tuesday.
The app still says zero generation though clear and sunny here - I've checked Fox cloud on the web and that says zero as well. Can't seem to connect to wifi - I've used Will's connect / reconnect video but keep getting a fail and can't work out why....
Let me know if you still need a photo - I can just about fit my phone down the gap