Newbe here.
I've had solar for 11 months now, and I've been trying to regulate its overnight charging by adjusting the time it charges for. I've now been forced to move over to using the Mode Scheduler and there are two parameters which look interesting, FCSoC and SoC, but I don't know how to use them.
What do these parameters actually do and how, for example, do I force an overnight charge to, say, 40% capacity?
I am beginning to go through some of Will Eccles's videos. Is there one in particular which explains them, or any other reference material?
TIA,
Nick
Here is an excellent post by Dave Foster that describes all the values.
viewtopic.php?p=10376#p10376
As for your post, the sad news is Fox have changed the behavior of the Firmware logic, so now it's a problem for getting it right so to speak.
viewtopic.php?p=10376#p10376
As for your post, the sad news is Fox have changed the behavior of the Firmware logic, so now it's a problem for getting it right so to speak.
Oh, that is a pain with the changes.
Thanks for the link.
I found Will Eccles video, https://www.youtube.com/watch?v=jhohbmt0U_w (Fox ESS - Complete guide to Work Modes and Mode Scheduler UPDATED 2026 -Force charge/Force Discharge), and it looks like it the phone app just changes the FCSoC, do I'll try changing that tonight.
Thanks for the link.
I found Will Eccles video, https://www.youtube.com/watch?v=jhohbmt0U_w (Fox ESS - Complete guide to Work Modes and Mode Scheduler UPDATED 2026 -Force charge/Force Discharge), and it looks like it the phone app just changes the FCSoC, do I'll try changing that tonight.
That's the way to work it, make a change and test the results to confirm.
There are a few methods to input settings, there is https://www.foxesscloud.com/v2/login website that you can use (Quick Settings top right)
Fingers crossed.
There are a few methods to input settings, there is https://www.foxesscloud.com/v2/login website that you can use (Quick Settings top right)
Fingers crossed.
The quick settings created the confusion as it exposes more parameters than the app. The app Mode Scheduler just changes FCSoC and has no control over SoC at all.
You can use whichever you are most comfortable/familiar with of course. It can be good to know there are other ways to adjust.
Best stick with the current way you like and check tomorrow.
Hmm. Using the phone app, setting a min SoC does not have the desired consequences. The inverter switched to Grid Import last night as the battery had more than 50% charge.
I am trying to set a backstop of a minimum of a 30% charge at the end of the cheap period, and do self-use otherwise (the default mode).
I am trying to set a backstop of a minimum of a 30% charge at the end of the cheap period, and do self-use otherwise (the default mode).
Hi Nick,
I could link you to a few threads in recent times that point to this exact issue.
The system is currently using the logic that if you set a 4pm to 7pm discharge down to xx% SoC it will reach the value and the battery stops discharging.
Now what happens is the system will import from grid until 7pm comes around. They are working on new firmwares to correct this, so it reaches xx% SoC and after 10mins (from what I can tell) it should swap work mode and the battery would carry on (depending on your fallback work mode)
Temporarily, all you can do is drop the time back to 6pm or watch like a hawk for the battery to reach your xx% SoC and then quickly change work mode. A PITA for sure.
I could link you to a few threads in recent times that point to this exact issue.
The system is currently using the logic that if you set a 4pm to 7pm discharge down to xx% SoC it will reach the value and the battery stops discharging.
Now what happens is the system will import from grid until 7pm comes around. They are working on new firmwares to correct this, so it reaches xx% SoC and after 10mins (from what I can tell) it should swap work mode and the battery would carry on (depending on your fallback work mode)
Temporarily, all you can do is drop the time back to 6pm or watch like a hawk for the battery to reach your xx% SoC and then quickly change work mode. A PITA for sure.
Yuck. I'm not getting up before 5am to check. Back to the old timed charge, then.
What is the mechanism for knowing that a fix has been released?
What is the mechanism for knowing that a fix has been released?
I'm very sorry I was distracted by some cooking. For some reason I was thinking you was on about evening peak discharge.
Talk about the wrong end of the stick.
Can you start from the beginning and tell us what you are trying to achieve in the morning charge during off-peak?
You might get a notification on your App about a firmware update, or there is a FW list section on Fox's website/this forurm (both take time to be updated)
I am trying to ensure I have a minimum charge by 5am to get me through to some decent sun generation in the morning. Currently the sun is kicking in at about 7am and I'd like enough in the battery to get up, boil the kettle make the toast and a little more, plus background usage. 30% is currently plenty to spare with the good weather.
In worse weather it is easy to adjust the schedule up to 100%.
I have been doing this by adjusting the time period for charging up to now but it is less than ideal.
In worse weather it is easy to adjust the schedule up to 100%.
I have been doing this by adjusting the time period for charging up to now but it is less than ideal.
I thought that was what you was doing, and running Self-use for normal running afterwards?
Me personally, I charge each night to 100% during the cheap rate, and have it be there for what I need it for.
I will admit this time of year, I discharge if the PV forecast looks good, so I have room to mop up excess solar (though work mode is Feed-in)
Do you get a decent export rate? It might be best if you just charged to 100% for now and this increases the export income.
Me personally, I charge each night to 100% during the cheap rate, and have it be there for what I need it for.
I will admit this time of year, I discharge if the PV forecast looks good, so I have room to mop up excess solar (though work mode is Feed-in)
Do you get a decent export rate? It might be best if you just charged to 100% for now and this increases the export income.
For me, cheap rate import is more than export, so the less I import the better.
I am hoping to move to an electric car or install a charging point. Then import goes down and I get an extra 2h to import cheaply. Export also goes up above import. At that point it becomes a no brainer to charge the batteries to 100% nightly.
I am hoping to move to an electric car or install a charging point. Then import goes down and I get an extra 2h to import cheaply. Export also goes up above import. At that point it becomes a no brainer to charge the batteries to 100% nightly.
Yeah that does make it hard, having to guess the charge amount daily.
You could just set a "dumb" charge, rather than using schedules. So Grid charge choice, and shorten the time of charge if you expect decent solar.
You can of course wait for a possible FW update, but won't help you now.
You could just set a "dumb" charge, rather than using schedules. So Grid charge choice, and shorten the time of charge if you expect decent solar.
You can of course wait for a possible FW update, but won't help you now.
It looks like forcing to x% charge now works.
I still don't have working a forced discharge to x% then have it switch to the default mode (Self Use). Currently it does the forced discharge then it pulls from the grid maintaining the target charge.
I still don't have working a forced discharge to x% then have it switch to the default mode (Self Use). Currently it does the forced discharge then it pulls from the grid maintaining the target charge.
Maybe a new FW update at some point will finally fix a lot of these issues.
Fingers crossed.
Fingers crossed.
I am experiencing the same - force discharge to x% - but if it gets to x% before the end of the discharge period it then imports from the grid to meet load instead of continuing to use batter y stored power.
As an example - if i export at 6kw it is roughly 20% per hour (I have 31Kwh of battery). I have had it set to export to grid down to 75% in the middle of the day as i know that I have at least 25% spare to export.
However - last week i forgot to plug in the car for the overnight cheap period. So I charged the car in the morning and took about 20% of the Fox battery to give myself some car range. Then came the middle of the day and the forced export down to 75% started (for an hour) but it hit 75% almost immediately. For the rest of the hour it imported power to satisfy house load from the grid at peak price - completely destroying any value from the export.
I looked into it and realised that the same happened on some days later in the evening when I was discharging down to 15%prior to the start (at 11.30pm). I was actually discharging in one hour segments each of 20%.
e.g. 20:31 - 21:30 Discharge to 55% at 6kw. 21:31 - 22:30 Discharge to 35% at 6kw. and so on.
If I hit the threshold it then Imported to maintain that level reather than defaulting to self use.
I have now moved all my export periods to the end of the day. Perhaps it would be better to have one early in the day to capture solar and reduce this unwanted import later.
Given that the price of imported power is so much larger than the value of exporting (export price minus overnight import price = value of stored power) it quickly destroys the economics.
A fudge will be to know that I export at 20% per hour so time an export in the day for a couple or three of hours to dump 40% to 60% but this means I wont be able to take advantage of days that I have less home use or more solar generation and set an ambitious export schedule with cut off thresholds which would export something like 80% of the battery.
I have air source heating and so some days can be big user days and others are small depending on how cold it is outside so if i dont use for heat i want to export and gain value.
Lets hope an "export to a threshold and then default to self use when reached" mode becomes available as it would greatly assist in achieving most value from exporting.
Attached is the work schedule (sequential force discharges ) that I would like to use if that were available. I could set it as one big dump down to 15% and achieve something similar.
Also attached is a compromise export schedule that exports a constant 60% being 20% in the morning leaving room for solar (5kw system) and then a further 40% in the evening simply measured by the time of export (1 or 2 hours x 6kw). - i just need to watch that i'm usually above 50% at 9.30pm. If I dont export down to 10% at least I don't purchase replacement power to recharge overnight.
Also attached is a graph showing the unwanted import later in the day - the small one earlier in the day is when I exceeded 6kw of house load and had to draw from the grid.
I'll be reviewing the while idea as i add more air source heating and a smart immersion heater.
As an example - if i export at 6kw it is roughly 20% per hour (I have 31Kwh of battery). I have had it set to export to grid down to 75% in the middle of the day as i know that I have at least 25% spare to export.
However - last week i forgot to plug in the car for the overnight cheap period. So I charged the car in the morning and took about 20% of the Fox battery to give myself some car range. Then came the middle of the day and the forced export down to 75% started (for an hour) but it hit 75% almost immediately. For the rest of the hour it imported power to satisfy house load from the grid at peak price - completely destroying any value from the export.
I looked into it and realised that the same happened on some days later in the evening when I was discharging down to 15%prior to the start (at 11.30pm). I was actually discharging in one hour segments each of 20%.
e.g. 20:31 - 21:30 Discharge to 55% at 6kw. 21:31 - 22:30 Discharge to 35% at 6kw. and so on.
If I hit the threshold it then Imported to maintain that level reather than defaulting to self use.
I have now moved all my export periods to the end of the day. Perhaps it would be better to have one early in the day to capture solar and reduce this unwanted import later.
Given that the price of imported power is so much larger than the value of exporting (export price minus overnight import price = value of stored power) it quickly destroys the economics.
A fudge will be to know that I export at 20% per hour so time an export in the day for a couple or three of hours to dump 40% to 60% but this means I wont be able to take advantage of days that I have less home use or more solar generation and set an ambitious export schedule with cut off thresholds which would export something like 80% of the battery.
I have air source heating and so some days can be big user days and others are small depending on how cold it is outside so if i dont use for heat i want to export and gain value.
Lets hope an "export to a threshold and then default to self use when reached" mode becomes available as it would greatly assist in achieving most value from exporting.
Attached is the work schedule (sequential force discharges ) that I would like to use if that were available. I could set it as one big dump down to 15% and achieve something similar.
Also attached is a compromise export schedule that exports a constant 60% being 20% in the morning leaving room for solar (5kw system) and then a further 40% in the evening simply measured by the time of export (1 or 2 hours x 6kw). - i just need to watch that i'm usually above 50% at 9.30pm. If I dont export down to 10% at least I don't purchase replacement power to recharge overnight.
Also attached is a graph showing the unwanted import later in the day - the small one earlier in the day is when I exceeded 6kw of house load and had to draw from the grid.
I'll be reviewing the while idea as i add more air source heating and a smart immersion heater.
Attachments:
Last edited by Danto on Sun Mar 29, 2026 7:13 pm, edited 3 times in total.
@Danto
I would suggest for your case usage, that Home Assistant might be the best long term choice.
Bonus if your heat pump/smart immersion can be controlled via HA.
I would suggest for your case usage, that Home Assistant might be the best long term choice.
Bonus if your heat pump/smart immersion can be controlled via HA.
@MaterialBarracuda48
Thanks - thats a rabbit hole I didn't know existed! Taking a look.
First thought is theres no alarm or output from fox ess system when you hit the force discharge state of charge threshold to use to trigger an action in Home Assistant but will look further.
Easiest would be for Fox to embed that logic in their own work mode.. but hey ho.
Thanks - thats a rabbit hole I didn't know existed! Taking a look.
First thought is theres no alarm or output from fox ess system when you hit the force discharge state of charge threshold to use to trigger an action in Home Assistant but will look further.
Easiest would be for Fox to embed that logic in their own work mode.. but hey ho.
No alarm, but there is HA logic settings.Danto wrote: ↑Mon Mar 30, 2026 8:10 am @MaterialBarracuda48
Thanks - thats a rabbit hole I didn't know existed! Taking a look.
First thought is theres no alarm or output from fox ess system when you hit the force discharge state of charge threshold to use to trigger an action in Home Assistant but will look further.
Easiest would be for Fox to embed that logic in their own work mode.. but hey ho.
You could set a time range for the start/end of your force discharge, and have it monitor the battery SoC. It can then change the work mode of the Inverter if the two logic rules are met (time and a value)
There are firmware updates coming along that should change this behavior, so when the SoC is reached it can then dropout and change to a default work mode IIRC.
I have an early morning schedule setup to check for a time (05:35) it then checks the solar forecast for the same day, and if the predicted PV output is above xxkWh, it will then change the work mode to discharge. If the solar forecast is below my value, it then does not change the work mode to discharge.
Wow.. i can tell that this is something I need to learn.. especially with all the other things I have going on in the house.
Where do you get your solar forecast?
Thanks
Dan
Where do you get your solar forecast?
Thanks
Dan
I have only scratched the surface on HA, I use it like a hammer (tool) to do a job. The possibilities for home control are very powerful if you have the right gear.
If you watch from about 6mins on, and then for bonus, head to around 9mins in. You can see a simple HA automation Will setup to show a visual effect through HA.
Some have also wired up a smart bulb in the home to change to green for when Octopus Agile prices drop below x pence per kWh, this tells when they can put on high energy items.
I can dig up a post where I yap on about the solar forecast to control my discharge if needed, but in short, there is a tool baked into HA or easily added called Forecast.Solar. It is not perfect, it is right about 95% of the time for my needs, and other more accurate tools can be used if you wish.
If you need more details or a picture, then ask away.
I raised an issue with FoxESS that when you do a force discharge, when it hits the FDSoC, home usage switches to Grid Import and Solar production then charges the battery rather than all going to the default Self-Use. A bit barking mad.
They have acknowledged it and replied:
Fingers crossed.OK i got what you mean, for current logic ,it does not support like you described, but in the next firmware we will achieve this
The firmware will be released around mid of April
Last edited by NickJH on Thu Apr 02, 2026 2:31 pm, edited 1 time in total.