Force discharge not working correctly

MaterialBarracuda48 · Tue Mar 17, 2026 11:16 am

andrewv wrote: ↑Tue Mar 17, 2026 11:12 am I can understand how some people will want something to work one way and some another.

But I'd say that forcibly changing the way something works, without warning, is an absolute no-no. If they want to introduce extra functionality, then they shouldn't do it at the expense of existing functionality. And let's face it, they're not deliberately introducing extra functionality here, they've done this by accident.

It has not made for the best customer experience, it works one day, then behavior changes overnight.

It was not an accident though, they made deliberate operating changes to what they believed their customers wanted

andrewv · Tue Mar 17, 2026 12:55 pm

I still don't understand why someone would want a time period where they force discharge (presumably because they are selling), then when it reaches a certain SOC to then immediately run from the grid for the rest of that time period (which will presumably be at an expensive rate as this is a time period when it's profitable to sell, not buy)...

Given that this happened at the same time as two bugs (disabling my forced charging and limiting my import power rate), I'm not convinced anyone at Fox knows what they're doing.

And yes, all of the above about not springing surprise changes in functionality on people, intended or not. This is not currently the system I carefully researched and bought. And we're here discussing this as we monitor things closely - there are going to be people whose first realisation that their systems are no longer working as they believed them to be is when the bills come in...

MaterialBarracuda48 · Tue Mar 17, 2026 1:29 pm

There is a previous post from a few months back where someone had the opposite problem with charging.
viewtopic.php?p=12379#p12379

So FcSoC % and FdSoC % just acts now as an instruction for the battery to Charge/Discharge to xx%
Then it rides out the time period.

I agree it would be nice if they can adjust this behavior somehow to change behavior once it reaches this value, could be a future firmware change or some toggle that can be adjusted.

We did have a Dutch member IIRC post not too long ago about AI Mode being present in the FoxCloud2.0 App in their region, maybe that could solve it. "Discharge battery down to xx% between xx:xx and yy:yy time" and it then swaps work mode. Sadly not sure if this has taken off, and how it works as I don't think they posted details on this.

ETA: Ah, here it is, have a read... I am not sure if it is mature and how people are finding it IRL
https://fox-ess.uk/capture-ai/

brunofabre · Tue Mar 17, 2026 8:58 pm

If your force discharge schedule has reached it's cutoff soc it will stop discharging full stop until the end of the schedule. If you don't want to draw from the grid from the time it reaches the cutoff soc and the end of the schedule, you only have two choices. Change the discharge schedule to a shorter period, or limit the discharge power. You should decide which is worse, not discharging to the grid as much as you want, or buying from the grid. For my situation I have stopped forced discharging all together as we get very little from it anyway.

andrewv · Tue Mar 17, 2026 9:46 pm

Thanks for the reply. Yes, I could do that, but I don't want to do either of those things as I don't know what the SOC will be at 8pm when I start discharging. It will vary according to the season and how much it's been used during the day. I have three forced discharge periods set up - 8-10pm to 48%, 10-11pm to 24% and 11-11:30pm to 12%. Then whatever the SOC is at 8pm and however much it's being used, it gets down to 11% at 11:30pm and it's time to charge it again at the cheap rate. And no importing from the grid at the expensive rate during the evening. To recreate this now I'll have to keep changing the rate or time depending on the season, how much I've used it each day etc.

I just want it to work how it did from when I bought it until three weeks ago, and I think it's quite reasonable to expect that.

DustyDT · Tue Apr 14, 2026 3:57 pm

Hi All, the last post I have seen on this problem was back in March and we are now coming up a month later on and yet I think the SW/FW has not been updated by FoxESS to address this issue. I would appreciate any feedback on whether Fox are actually going to revert controls back to the old system such that we can continue to use FD without incurring grid imports at peak rates or whether the only option is go down the Home Assistant route (which i think is beyond my skillset...)?
Thanks

andrewv · Tue Apr 14, 2026 5:59 pm

I have been chasing my installer - the last I heard was on 26th March when they said, "Sent your further feedback to them [Fox]. I'll update you on their response". So I guess I'll just keep chasing them. I'll post any further updates here.

MaterialBarracuda48 · Tue Apr 14, 2026 6:01 pm

The last word was "April" so you may have to wait a bit more before they release something. The latest FW release for the KH series was pulled, so I would rather wait a few weeks and get a stable release.

DustyDT · Fri Apr 17, 2026 2:26 pm

I hope it's OK to bring this up within this thread but it does relate directly to the words of the subject line:
I experimented with setting a Forced Discharge whilst the sun was still shining (so there was PV output) and was surprised to see that when I set FD to 6kW the actual battery discharge level was considerably less than the 6kW requested - in fact exactly the PV amount less (in this case PV was running at 4-5kW so only 1-2kW was being actually discharged from the battery). So this means that the actual battery discharge power is the set FD power less the PV power at the time..... I cannot follow why this should be the case, if I demand discharge then surely that's the rate that the battery should be discharged by? (Note at these levels I was well below the inverter power limit so that shouldn't have impacted the discharge power)

Fri Apr 17, 2026 3:30 pm

DustyDT wrote: ↑Fri Apr 17, 2026 2:26 pm I hope it's OK to bring this up within this thread but it does relate directly to the words of the subject line:
I experimented with setting a Forced Discharge whilst the sun was still shining (so there was PV output) and was surprised to see that when I set FD to 6kW the actual battery discharge level was considerably less than the 6kW requested - in fact exactly the PV amount less (in this case PV was running at 4-5kW so only 1-2kW was being actually discharged from the battery). So this means that the actual battery discharge power is the set FD power less the PV power at the time..... I cannot follow why this should be the case, if I demand discharge then surely that's the rate that the battery should be discharged by? (Note at these levels I was well below the inverter power limit so that shouldn't have impacted the discharge power)

That's the thing FD whilst implying force discharge power rate is not related to battery discharge, it is actually setting the inverters active power register to 6kW and so the inverter will fix it's AC output at 6000 watts. Assuming it is capable of achieving that it will fulfill it firstly through PV and use battery to fill in the rest (plus losses), so you'd expect to see a few hundred watts more going in than coming out.