FoxESS Community - Owners & Installers Forum

Just had my pv system installed today. I requested the EP11 with heater which the installer said was available and I confirmed this morning that's what was being installed.

How is it supposed to work? I can't see any options in the fox app for heating and the battery temperature hasn't gone above 3°c since they switched everything on this afternoon. Is there anything I need to do or do I need to wait for any reason?

Morning,

For the heater controls to appear in the app you need the fox v2 app to be on the latest version so check the app store. You'll also need the latest inverter and battery firmware to be installed by your installer.
Once this is done you'll see the heater controls under devices > battery at the bottom of the screen near mode scheduler.

Might also be worth posting a picture of the model details sticker on the side of the battery so i/we can confirm you do have a heater model as there is a great deal of confusion about which have and don't have a heater currently.

Also worth noting that this option only appeared in the app over the last week or so and appears to be buggy on initial release so don't worry if it's not working perfectly until the next batch of fixes are released.

Looking at the feedback from Fox here: viewtopic.php?t=1127 your model number will have a H in it if it does have a heater like EP11-H

Hi Will,

Thanks for your reply.

Is there any way to check the firmware versions in the app or is this only available on installer mode?

I'll post a photo of the sticker when I get home tonight, I'm pretty sure it didn't have a -H on it though so I'm not totally convinced it's the heated one.

Don't mind too much if it's just firmware but want to make sure it's the right model.

Many thanks
Scott

You can see the firmware when you login to the cloud desktop version https://www.foxesscloud.com/

Hi Will,

I have asked the installer to check the firmware versions.

This is the sticker on the battery In the desktop version is shows version on battery master as "1.005" is that the firmware? Can't see where else the firmware version would be listed

Many Thanks
Scott

That doesn't look like a H model so no heater. Current firmware for the EP is 1.006 so nearly up to date. Your inverter firmware will also need to be the latest but if on the latest and no battery controls then it's highly likely you don't have a heater model.

Hi Will,

I've contacted the installer to see if they can get all the firmware up to date. Hopefully they can sort it out if its not the right one! Definitely need that heater in this weather!

Installer has been updating the firmware today, alas still no controls for heating so I'm assuming it's not the heated model. I'm hoping the installer will be able to sort it

Ok so firmware fully updated and heating looks to be working now! Its a little confusing how its works and was properly hidden in the app and I only found it by chance. It was under the "Quick Settings here" menu!
It seems that they're just quietly replacing them with the heated version without changing the model name as the EPs on the Fox website all advertise a heater but aren't given a different name. https://uk.fox-ess.com/ep-batteries/

So as you mentioned the heating function is very buggy!

It only seems to heat from the grid between the hours you set ( I assumed it would be able to heat from it's own capacity throughout the day as well)

And a couple of times after heating it doesn't discharge at all and only pulls from the grid until I turn off the heating function then it kicks in again.

Fingers crossed they improve this soon!

Hello, found this thread via Google and think I'm in the same boat as Scott.

Had my system installed a week ago - the fitter informed me that I've got the EP11 with heating element (wasn't what I was quoted for, but the quote was generated before the EP11-H was on the market). For what it's worth the label on it looks the same as Scott's.

I've got the 'Battery warmup' options on the app, but as far as I can tell it doesn't seem to be functioning. I've set the schedule for 'warmup slot in low price' to coincide with my off-peak rates overnight, but it never seems to warm the battery. And in this cold weather that means it will only charge at about 850 W!

I've had the inverter (H1-G2) firmware updated from 1.21 to 1.31, but that doesn't seem to have made any difference. The BMS firmware is 1.005.

@Scott - is your battery heating now functioning? What inverter do you have, and with what firmware version?

I guess I'm wondering if it's just a matter of waiting for the software/firmware to mature, or if I should be pro-actively asking anything of my installer to get it to kick into life.

Following up on this, in case it helps anyone else in future.

I raised it with my installer, who consulted with Fox. There were two main actions that now mean I have a functioning battery heating system (just in time for the weather to warm up ):

1. Most importantly, a BMS firmware update from 1.005 to 1.006. When the firmware update was applied my battery actually stopped working, and it took two rounds of power cycling the inverter and battery to get everything back (first power cycle brought the battery back, but no battery heating option at all, second power cycle restored the battery heating option).

2. Secondly, the 'warmup slot in low price' time settings cannot span midnight, i.e. if you want 23:30-05:30 you'll need to use two slots: 23:30-23:59 and 00:00-05:30. This is the same behaviour as the Mode Scheduler, but unlike the Mode Scheduler it didn't throw an error and instead just silently failed.

With these fixed the battery heating kicked in. Happy days.

Does anyone know the recommended temperature settings - min and max please ?

Many thanks
Russell

RussJH wrote: ↑Wed Apr 30, 2025 3:24 pm Does anyone know the recommended temperature settings - min and max please ?

Many thanks
Russell

The ideal temperature range is between 20C and 30C, the batteries are capacity rated at 25C

Great, thanks

Can I confirm if these models are likely to be able to be mixed in future as the non heated version seems to be getting less available? I would have thought that a check to confirm if they all have heaters via the firmware and disable if not would be feasible but may but more complex than that. My non heated EP11 is in my garage so I am not too worried tbh but I don't want to get in a position that I can't expand the pack because the EP11 non heated becomes scarce

You can add a heated EP11 to a stack which has a non-heated EP11, it'll work fine, except that you can't use the heating function.

Also make sure that you update the battery firmware so that they match.

Can I follow onto this with a question or two....

My battery firmware is 1.006.

I have mode scheduler set to force charge 11:30pm to 5:30am. This worked perfectly before.....

I've just been through all this figuring out if the EP11 was the heated model or not (found the WARM sticker); and then becoming luckily enough to get the settings to appear in the app yesterday.

I immediately activated this; I thought I'd give my battery the luxury treatment: activate the heater as soon as possible (9 degrees); heat until hottest possible (15 degrees). Also, heat from the grid during my cheap tariff: 11:30pm to 5:30am again.

Today; not sure if the heater kicked in at all, but the battery did not charge at all.

I can't find anything clear on this: should the heater be able to heat AND the battery charge at the same time, or does it prioritise one by blocking the other? .

I'm also noticing this oddity: my batter min SOC is 10%. It usually runs down to 10% but right now, SOC was c. 15% and not discharging. On the app, the inverter has the little orange symbol and says 'warmup standby' when I click on it (and it takes me to the battery warmer settings) - this is despite the battery temperature being 14.2 degrees (way above when the battery warmer is supposed to kick in - I've deactived and reactived the heating / changed the 'heat to' temperature to be 10 degrees so it shouldn't be an overhang of trying to heat to 15 degrees...). is anyone else noticing this strange behaviour?

danielk wrote: ↑Wed Nov 12, 2025 6:41 pm My battery firmware is 1.006.

Mine has been 1.005 / 1.05 since the start

danielk wrote: ↑Wed Nov 12, 2025 6:41 pm I immediately activated this; I thought I'd give my battery the luxury treatment: activate the heater as soon as possible (9 degrees); heat until hottest possible (15 degrees). Also, heat from the grid during my cheap tariff: 11:30pm to 5:30am again.

Make sure to use 2x slots, 23:30 - 23:59 and 00:00 - 05:30 if you have not already.
Mine has min temp set at 0 C and max 22 C (in real life it never gets to 22 C in the cold, but it's in garage)

danielk wrote: ↑Wed Nov 12, 2025 6:41 pm Today; not sure if the heater kicked in at all, but the battery did not charge at all.

I can't find anything clear on this: should the heater be able to heat AND the battery charge at the same time, or does it prioritise one by blocking the other? .

I'm also noticing this oddity: my batter min SOC is 10%. It usually runs down to 10% but right now, SOC was c. 15% and not discharging. On the app, the inverter has the little orange symbol and says 'warmup standby' when I click on it (and it takes me to the battery warmer settings) - this is despite the battery temperature being 14.2 degrees (way above when the battery warmer is supposed to kick in - I've deactived and reactived the heating / changed the 'heat to' temperature to be 10 degrees so it shouldn't be an overhang of trying to heat to 15 degrees...). is anyone else noticing this strange behaviour?

I have not checked to see if it heats at 00:30 (my start time) but now it is in standby.

AFAIK it should charge at same time as heating, the heating element I think is only 200-300W (maybe someone knows better)

The battery may have dropped down to 10% then "recovered" mine has been down to 9% once and within a few mins it will increase up to 12-14% as the cells settle and BMS does some recalcs.

There has been some app bugs, so maybe something has changed... check your charging schedules to make sure that the values make sense, you might need to set in your charge schedule the FD PWR to match inverter, if 0W set to say 7000

Quick question - sorry to go off topic a little, but like many my warm-up function isn’t kicking in so my recharging is seriously throttled. I contacted my installer and they’ve told me to contact Fox directly to get my firmware upgraded. The battery is at 1.005.

Calling Fox on the number they gave me the automated message basically says they only talk to installers/agents, but there is an email address. If I email with the serial numbers etc. of my battery and inverter will they up the firmware without an issue?

TIA

Ferryhill9 wrote: ↑Sun Nov 16, 2025 12:27 pm Quick question - sorry to go off topic a little, but like many my warm-up function isn’t kicking in so my recharging is seriously throttled. I contacted my installer and they’ve told me to contact Fox directly to get my firmware upgraded. The battery is at 1.005.

Calling Fox on the number they gave me the automated message basically says they only talk to installers/agents, but there is an email address. If I email with the serial numbers etc. of my battery and inverter will they up the firmware without an issue?

TIA

TBH Your installer really should be able to do it, but if you go to the app click on 'Me', 'Contact Us', 'Support' and fill the form in - let Fox support know your battery heater isn't working and firmware is old and they will usually respond within 48 hours.

Thanks Dave. I’ve sent an email with all my info to ‘service.uk@fox-ess.com’ so hopefully that’ll have the same effect as filling the form in. I must say I was disappointed with my installer. They fitted my system in June and the battery firmware is 1.005, from this thread it appears firmware 1.006 was available in January so they really should have flashed it before installing.