EP11 with heater

[MaterialBarracuda48]

How are people rebooting their batteries to see if that makes any difference? My manual says I can do a battery shut-down and start up as per attached (hold power switch for 5 seconds etc and then start again with another 3 second power switch press)? Is anyone fully resetting their inverter as well? I've got a DC switch on the battery - I'm assuming I can leave that alone when doing the battery power switch reset? Any advice or insight is appreciated! TIA.

I would also turn off the battery DC Switch, as this could still be sending power to the BMS inside.

When turning it all back on, I start power the battery on before rest of system.

[albie999]

I am just totally confused now ..... so, based on the email from Fox that I posted ....... is it saying that basically ... I can either

1) "warm" up the bateries and not be able to charge or discharge (therefore pull from the grid)
or
2) can charge / discharge and power the house but the batteries gradually get colder and colder?

Example now .. that ... pulling from Solar and 100% charge ... but .. battery temp is dropping ... as I have turned off the heating module ... as if I turn it on ..... I then start pulling from grid .. even though I got battery

Anything I can do .. temps are still dropping .. now down to 5.5c ... but cannot turn on heater .. as will draw from grid?

[Arwith]

I have the exact same issue at the moment, looks to be my firmwares are out of date so i can see the warming option but it's greyed out in the app... I've contacted my installer but they haven't got a scooby, so have emailed fox ess and hopefully they can arrange a firmware update.

One thing i have noticed in the app is that when using the mode scheduler, even though i set my batteries to charge between lets say 4am and 7am (as these are my current cheap times), it was actually charging between 1am and 4am... a 3hr time difference that used to be a 4hr time difference when we were BST. When setting times via the fox ess cloud everything is fine, but the time zone in the app appears to differ, so i wonder if perhaps the issues people are having with the warming of the batteries could be related?

perhaps you are instructing it to warm up between a certain time but the timezone offset is messing things up? unless there is already a known way to resolve the timezone issues in the app....

only day I've had any issues was today, work up to my batteries sitting on 17% having charged a whopping 2% overnight as opposed to the usual 60-70% it normally does, it's at least good to see that i'm not the only one facing issues as hopefully that means Fox will do something about it!

[albie999]

Is just so wierd ... turned on heater to see what would happen (as it is continally getting colder) .. and it just killed everything .. even solar .. and drew from the grid .. no idea at all ... switched heater back off ... and all came back to life

[hamgeezer]

Is just so wierd ... turned on heater to see what would happen (as it is continally getting colder) .. and it just killed everything .. even solar .. and drew from the grid .. no idea at all ... switched heater back off ... and all came back to life

battery6.jpg

Did you get a fault code when you did that? I had a fault code every 4 min today "Output Over-Current Fault" which went away when I turned the battery heater off.
My battery firmware is 1.006.

[albie999]

[/quote]
Did you get a fault code when you did that? I had a fault code every 4 min today "Output Over-Current Fault" which went away when I turned the battery heater off.
My battery firmware is 1.006.
[/quote]

Where would i see the fault codes?

[hamgeezer]

Where would i see the fault codes?

If you use the Modbus integration you should have an entity called sensor.inverter_fault_code.

This was mine (note all the different coloured lines after noon until when I disabled the battery heater:

There will also be something on your inverter display when it's happening if you're brave enough to go out in the cold

[albie999]

All seemed to be clear for me

[hamgeezer]

Interesting! So your issue is different to mine. Maybe I have a busted heater.

[RussJH]

Last two days, around midday, my battery heater cut in for about 30 mins. It's set to come on during the overnight cheap rate as suggested by Will, so it must do that autonomously.

However this PM it was not supplying any power and sat at 9.3c. No amount of fiddling with the heater settings would start the heating process, or produce any output from the battery.

Eventually, I turned off the heating feature complete and bingo, battery back supplying power again.

[jamescl13]

Same issue here, heater not kicking in as it should. Battery not wanting to do much in the mornings because it is seemingly too cold. Heater settings not kicking things into action, the 'warmup slot' not working from the grid and the battery not being used to heat the batteries to the required temp when the SOC is quite high.

EP11 battery 'H' model 1.007 firmware

[Ferryhill9]

Yes, it was originally set to 00:01-23:59, I set it to 0000-2359 as suggested in the thread. No difference.

Sorry to hear that it hasn't worked, I guess they are going to have to fix this out ASAP or a lot of people will be hopping mad.

Update - I’ve figured out the warm-up function on my battery is actually working as it should. The problem was operator error. I assumed that if you switched the warm-up function on the battery would ramp the heat up until it hit the upper figure (End) set on the app.

That’s not the case. On my system at least, if you switch the heater on, nothing happens until the temperature falls to the low (Start) slider setting. This triggers the heater_on and the temp rises until it reaches the high (End) slider setting, this triggers heater_off and the battery starts to cool down. The system keeps cycling between these two temperatures.

I originally had the ‘Start’ slider at 3° and the ‘End’ slider at 15°. While investigating I set the ‘Start’ slider to 8° when the battery cells actual temp was around 5°, the heater started immediately and slowly rose to 15°.

I’ve been monitoring this all day before posting, and it’s cycled up/down using different high and low temperatures 3 or 4 times, so I’m confident it’s correct. A few things to note -

1. I set the upper temp to 15°, it actually goes up about 1° above that.
2. If you set (Submit) new ‘Start’ and ‘End’ temperatures at any time in this cycle the heater switches off, even if it’s still rising, and you have to wait until the battery drops to the ‘Start’ setting again before the heater switches on again.
3. Although ‘Warmup slot in low price’ is set nothing was taken from the grid. The most drawn from the grid shown on the app was never more than 20w all day, and I’m led to believe the heater is 200-300w. Little or no PV today so the battery was providing the power for the heater.

EP11 Battery Firmware 1.009

[MaterialBarracuda48]

@Ferryhill9

Nice feedback on getting the software worked out, hopefully I will get a firmware update soon and can get it working.

[KEVSTER]

Hi all new to the forum, and Thanks for the info.

I’ve been playing with the settings
And after the firmware update I’ve got the battery heating options but I’m not able to get the heating element to switch on?

Have I done something wrong?

Current lower setting is 10 degrees.
Upper temp is 19 degrees.

Battery temp is 1.4 degrees.

No schedule selected currently.

Battery shows warmup stanby with orange symbols.

I would attach a screen shot but haven’t figured out how to do that yet.

[iew100]

I've requested my installer to do an upgrade to 1.009 firmware for my EP11s. Let's see if that helps resolve the heating issues.

[RussJH]

Set mine as per screenshots yesterday and it now seems to be working more reliably

[KEVSTER]

Well mine seems to have started working when it reached 0 degrees.

Perhaps now i’ve set it to 10 at the lower limit it will reset its self and not go below.

Will report back tonight.

[iew100]

My EP11 batteries start warming when PV is above 1kw and can push around 700w into the batteries after house base load. The heating just doesn't work reliably from internal battery or grid power. I'm waiting for the 1.009 firmware upgrade to see if that makes any difference.

[albie999]

So, this morning Fox updated the firmware on my inverter and also on the EP11 battery (to 1.009). I have enabled the battery warmup function, and it does look like my battery is now warming ... gone up 6c in the last hour ... as well as allowing the solar to function ... and some battery charge (although for some reason ... the battery is only charging slowly .. even though a lot of solar is available) ... wonder if these could still be an issue with warming and charging/discharging?

So .. for now ... things do seem to be better

[albie999]

For info .. as soon as the battery heated up and the heater auto turned off ... the battery charge rate jumped up .. so there does still seem to be a minor issue

[Dave Foster]

Will has been speaking with Fox and confirmed the 1.009 firmware is where you should be, also the actual operation is slightly different than I thought, so worth watching this video and note the 40% SoC limit. https://youtu.be/_9hNCI1bTP4?si=oC4khit641SJd2TM

[RussJH]

Set mine as per screenshots yesterday and it now seems to be working more reliably

Confirm mine has now warmed itself 3-4 times per day with the settings previously shown.

Currently on 1.07 but have asked to upgrade to 1.09

I can't see the point in not having charge from grid set for 24 hours. If you are below 40% during the day and there is no PV, then the battery won't warm.

[doubl0dave]

Set mine as per screenshots yesterday and it now seems to be working more reliably

I can't see the point in not having charge from grid set for 24 hours. If you are below 40% during the day and there is no PV, then the battery won't warm.

I charge my battery full (or close to) overnight on cheap rate (export solar for higher price if I get some) so I have turned off charge from grid in daylight hours. If PV is low, the battery will keep itself warm, but if the sun shines then it heats and charges the battery. But if you don't charge your battery overnight or need every last kW of energy for house usage, than you probably need it on 24/7.

[Arwith]

Managed to get a response from fox support and they remotely updated the firmware on everything, unlocking the warming feature in the app, however, with it turned on the battery appears stuck in "warmup standby" no matter what settings i put, and seemingly while it is in warmup standby the battery cannot charge from the grid seemingly. Essentially since having it on the batteries have just drained to their minimum SOC charging only a trickle with what sun we've have thus far today.

I decided to then only have the warmup feature enabled during non-cheap rate times so hopefully it wouldn't be trying to warm the batteries when i need them to charge, though i'm sceptical it will actually work given for some reason there are timezone issues within the app for me. If I set timings via fox ess cloud there are no issues, but via the app there is a 3-4 hour offset from the time i am setting to the time it actually does stuff (noticed on mode scheduler setting charge times) so am a little worried i'm going to have to try and guess things if the battery times don't work.

Since there is no feedback as to when the warming does and doesn't start, it's a little tricky to know if the settings are correct so i'm just going to have to hope....

In addition to this blocking of charging, I've noticed inconsistencies between the reporting from fox ess cloud and the app. Currently my battery temperature in the app is saying the batteries are 6c, the warmup feature is on and it's climbing by 0.1 every 5 minutes or so so hopefully it is actually heating. However, the fox ess cloud data is showing the battery temperature as much hotter (which doesn't make much sense as it's 6c outside). The app is most likely correct, just odd that there would be different reporting

Screenshot 2025-11-25 110948.png (11.25 KiB) Viewed 612 times

[MaterialBarracuda48]

@Arwith Can you tell me when you put in your support ticket please?
I put one in on the morning of the 20th, and it just sits at processing.