Good morning,
First post here.
We had a Fox solar PV system installed in August last year and it's been working a treat.
We have the following kit:
Inverter H1-5.0-E-G2 (Master 1.51, Slave 1.04, Manager 1.69)
Battery ECS2900-2 (BMS 2.012)
Logger WW (2.03)
I upgraded the firmware to the above on Monday and since then the Backup Mode now seems to work differently.
Before the upgrade in backup mode all the PV power was sent to the battery, which was great as we could charge on solar on cheaper grid days and then use the battery on days that were more expensive.
Now it seem to prioritize the house load first with only the excess PV going into the battery. I am operating under the assumption that the firmware update has changed something as we want the battery to charge first in backup mode.
Any help would be appreciated.
Thank you
Mick
Afternoon Mick,
Welcome to the forum.
I am not sure what has been changed, reading the FW release notes does't show what might have been changed.
https://fox-ess.tech/firmware-release-notes/
That being said, Fox do change settings and maybe it was this way in a previous FW that is not listed in that release notes page (as they have only just started doing this)
It does sound as if you are using Octopus Agile, but that is best guess.
You mention you use PV to charge the battery when the grid is on a cheap day, would it not be best to use grid charging and export maximum solar?
I appreciate we all use our system differently, so what works for you is the best.
Welcome to the forum.
I am not sure what has been changed, reading the FW release notes does't show what might have been changed.
https://fox-ess.tech/firmware-release-notes/
That being said, Fox do change settings and maybe it was this way in a previous FW that is not listed in that release notes page (as they have only just started doing this)
It does sound as if you are using Octopus Agile, but that is best guess.
You mention you use PV to charge the battery when the grid is on a cheap day, would it not be best to use grid charging and export maximum solar?
I appreciate we all use our system differently, so what works for you is the best.
Thank you for the response.
We are on Octopus Tracker and the cost per Kw on low days during the winter exceeds the feed in tariff.
For example today we are at 20.91 ppKw which is the lowest it's been for a while. It make sense to load the battery from PV today as tomorrow the cost goes up.
I'm not sure if the PV feed priority has been changed with the firmware update, but it used to put all the PV in the battery in Backup mode and now it prioritizes the house load.
We are on Octopus Tracker and the cost per Kw on low days during the winter exceeds the feed in tariff.
For example today we are at 20.91 ppKw which is the lowest it's been for a while. It make sense to load the battery from PV today as tomorrow the cost goes up.
I'm not sure if the PV feed priority has been changed with the firmware update, but it used to put all the PV in the battery in Backup mode and now it prioritizes the house load.
Going off topic a little here...
I do wonder if Agile would be a better fit, the last month if you compare the averages, Agile beats Tracker. Though it does not work for all.
Flux is better perhaps if you can charge 02:00 to 05:00 and battery has the capacity to ride out the rest of the day?
As for your subject matter, I am not sure, but maybe someone will respond to assist.
I do wonder if Agile would be a better fit, the last month if you compare the averages, Agile beats Tracker. Though it does not work for all.
Flux is better perhaps if you can charge 02:00 to 05:00 and battery has the capacity to ride out the rest of the day?
As for your subject matter, I am not sure, but maybe someone will respond to assist.
Just to add to my confusion. The system is set to backup mode but the battery is now discharging. I would have thought that in backup mode the battery would not be used?
Well that Q4.2025 and Q1.2026 Fox have been making many changes to FW behaviors and system backend settings.
So this could explain the "odd" behaviour you are not expecting.
With my KH Inverter, I can make a schedule that will charge and hold battery, just depends on your needs.
For more fine tooth control, you may have to look at Home Assistant perhaps, unless you are fine with manually adjusting daily.
So this could explain the "odd" behaviour you are not expecting.
With my KH Inverter, I can make a schedule that will charge and hold battery, just depends on your needs.
For more fine tooth control, you may have to look at Home Assistant perhaps, unless you are fine with manually adjusting daily.
I’ll be honest, the original behaviour of backup mode was that it had the same logic as self use in that it always covers house load first, and the remainder goes to the battery but the battery should never be used unless the inverter is running in EPS mode (grid power failure).
So now i’m not entirely sure whether the way it was working for you was the bug, and now they’ve fixed it…
it’s been a while since I tried that workmode. My inverter is a gen 1 which hasn’t had any updates for some time (it’s very reliable so that’s no bad thing) but i’ll test it asap to find out whether it still works the way it used to.
So now i’m not entirely sure whether the way it was working for you was the bug, and now they’ve fixed it…
it’s been a while since I tried that workmode. My inverter is a gen 1 which hasn’t had any updates for some time (it’s very reliable so that’s no bad thing) but i’ll test it asap to find out whether it still works the way it used to.