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Fox EP12+ battery
Posted: Tue Mar 17, 2026 10:39 am
by janu
Hi Folks, After some info, I have a newly installed Fox system consiting of 18 x440w Jinko panels, 1x 11.52 kw EP12+ battery, 8kw Fox inverter and Fox EPS backup gateway.
Is there a schematic or diagram/video explaining how to add a second EP12+ battery to my system, i have just obtained a brand new battery locally and would like to install it I have already ordered a junction box.
Re: Fox EP12+ battery
Posted: Tue Mar 17, 2026 6:37 pm
by nrb501
See pages 20-23 of the manual
https://midsummerwholesale.co.uk/pdfs/uk-ep-manual.pdf
The battery with the BMS cable direct to the inverter becomes the master.
Obviously shut the system down completely before connecting the second battery, the new battery will be recognised automatically at power-up.
Re: Fox EP12+ battery
Posted: Tue Mar 17, 2026 7:12 pm
by MaterialBarracuda48
I could be wrong, but make sure old and new have around 50% SoC before you "pair" them up.
Once working, it might be best if they are on same FW versions ideally.
Re: Fox EP12+ battery
Posted: Tue Mar 17, 2026 8:06 pm
by nrb501
Both good points. When I installed my second battery I had an error on the inverter until I had both batteries at the same version ("BMS Ver mismatch" I think it was)
Re: Fox EP12+ battery
Posted: Tue Mar 17, 2026 8:09 pm
by MaterialBarracuda48
Thanks @nrb501, I was worried if the FW could cause trouble.
Re: Fox EP12+ battery
Posted: Tue Mar 17, 2026 8:16 pm
by nrb501
Glad you mentioned the firmware as I had forgotten about that - it did give me an "oh s***" moment when the error came up, it updated ok though even with the error present.
Re: Fox EP12+ battery
Posted: Tue Mar 17, 2026 8:21 pm
by MaterialBarracuda48
"Code Brown"
Re: Fox EP12+ battery
Posted: Wed Mar 18, 2026 3:41 pm
by janu
Thanks everyone for the info.
Re: Fox EP12+ battery
Posted: Mon Mar 23, 2026 7:42 am
by janu
Hi Folks help required again, I have installed a second 11.52kw ess+ battery and junction box, upon reenergising the system evrything came back to life but I have a red exclamation mark on the inverter with the wording "batt volt fault" Help Please.
Re: Fox EP12+ battery
Posted: Mon Mar 23, 2026 12:27 pm
by MaterialBarracuda48
What lights are you seeing on the side of the battery, they should show a pattern that determines fault.
Re: Fox EP12+ battery
Posted: Mon Mar 23, 2026 12:53 pm
by janu
Hi I have code 234 and code 195 showing on the app
Re: Fox EP12+ battery
Posted: Mon Mar 23, 2026 12:58 pm
by MaterialBarracuda48
Error code 234 for the BMS is comms fault IIRC.
Error code 195 seems to suggest battery is in overcurrent or the cells are not in balance.
Do the red & green lights on the side confirm the pattern?
Re: Fox EP12+ battery
Posted: Mon Mar 23, 2026 1:02 pm
by janu
yes red light on both batteries and flashing green
Re: Fox EP12+ battery
Posted: Mon Mar 23, 2026 1:03 pm
by MaterialBarracuda48
janu wrote: ↑Mon Mar 23, 2026 1:02 pm
yes red light on both batteries and flashing green
There will be a pattern to this, and exists in your EPxx manual to check what the colour codes mean.
Hard to say what the fix is, you may have wired up the batteries wrong for power/comms?