FoxESS Community - Owners & Installers Forum

I have a full stack EQ4800 and I have noticed that the 1st module firmware version (1.15) is different to the other 8 modules (5.04). The other 8 originally had 5.02 until I requested an update to 5.04 but the 1st one stayed the same. Is this normal for the 1st module as it is physically different to the others?
The only other firmware available other than 5.04 on FoxCloud for my battery is 1.15. Should I flash that and then retry 5.04?

Take a look here, and read the additional notes.
viewtopic.php?p=8069#p8069

At the bottom you can see that you may have different Hardware versions, which is what I would bet upon.

MaterialBarracuda48 wrote: ↑Mon Jan 19, 2026 9:51 am Take a look here, and read the additional notes.
viewtopic.php?p=8069#p8069

At the bottom you can see that you may have different Hardware versions, which is what I would bet upon.
EQ Firmware.png

Thanks for pointing that out. How do you access the additional notes?

spurf wrote: ↑Mon Jan 19, 2026 10:35 am Thanks for pointing that out. How do you access the additional notes?

Click on linked post, scroll down to bottom of spreadsheet.

Your upper battery is the ‘-M’ which is the battery stack master (and has an internal slave @ 1.15), the remaining units are ‘-S’ which just contain the slave and they run a different firmware version.

So when you look at your stack you will have 1 firmware version for the slaves (BMU) and the other is the master (BCU) which is always the top battery.

MaterialBarracuda48 wrote: ↑Mon Jan 19, 2026 10:47 am Click on linked post, scroll down to bottom of spreadsheet.

All I can see in the Release Notes section for mine is "Release Notes" - am I missing something?

Dave Foster wrote: ↑Mon Jan 19, 2026 11:06 am Your upper battery is the ‘-M’ which is the battery stack master (and has an internal slave @ 1.15)

That makes sense, thank you. So is the reason that the internal slave firmware for the stack master isn't updated like the others because the master firmware overrides it functionally?

spurf wrote: ↑Mon Jan 19, 2026 11:49 pm All I can see in the Release Notes section for mine is "Release Notes" - am I missing something?

Sorry, probably posted before coffee yesterday.

Release notes don't really exist from Fox, I was meaning to say the version values though suspect you now know.

MaterialBarracuda48 wrote: ↑Tue Jan 20, 2026 8:53 am Sorry, probably posted before coffee yesterday.

Release notes don't really exist from Fox, I was meaning to say the version values though suspect you now know.

Weird that they don't post release notes. Would think it is in their best interests, so that customers aren't constantly pestering them to apply minor updates

Does it make any difference if you mix the EQ batteries in a stack if they have different hardware versions eg. V1.15 with V5.04.

How do you get Fox ESS to update them if they are different hardware, is there a risk of updating the wrong firmware on the wrong hardware?

keys wrote: ↑Wed Jan 21, 2026 11:31 am Does it make any difference if you mix the EQ batteries in a stack if they have different hardware versions eg. V1.15 with V5.04.

How do you get Fox ESS to update them if they are different hardware, is there a risk of updating the wrong firmware on the wrong hardware?

I think the Master has the 1.15 version, and the slaves have 5.04 version.
Rather than being different hardware versions.

Hopefully Dave/Will can confirm this is correct.