FoxESS Community - Owners & Installers Forum

Hi - here's my scenario - any help most appreciated!

Hardware as per signature below.

Current firmware at (date of posting) is :

Inverter:
Master : 1.47 (1.51 requested and in Fox ESS queue for real-time updates)_
Slave : 1.04
Manager : 1.33 (1.35 requested)
Integrated datalogger : 2.06 (2.08 requested)

Batteries:
Master 2.008 (2.012 Requested)
Slave : 1.15

Issue :

Scenario 1 : When system is set to self use ALL solar generation is used first for battery top up, second for house load, and third for export - as expected.

Scenario 2 : When an automation kicks in (via Home Assistant Modbus Control but the same issue happens with Mode Scheduler) to set the battery force to charge (HA automation so that when Intelligent Octopus Go rate is £0.07 which can happen/change at varying times throughout the day as Octopus manage the cheap slots), any excess PV generation is CLIPPED to whatever the BMS has set the max charge current to (this is, obviously, dependent on factors such as temperature and SoC as well as available PV generation) as opposed to being used for house load (at least!) and then any further excess being exported.

My EV Charger is "upstream from" and "invisible to" the inverter so that's not an issue.

HA is setting Registers 44000 = 1, 44001 - 65534 and 44002 to 60536 to start a force charge and 44001 = 0 to stop a force charge. I took advice from the integration author (TonyM 1958 integration in use which supported H1 - G2 inverters before the Nathan Marlor integration did) for this and if the values need changing can anyone please advise?

What I believe should happen :
When the battery is set to force charge (by whatever means) any excess PV generation over that being after that used by the BMS is then used for house load first and then any further excess is exported.

I'm currently losing several KWh of PV generation per day even in January!

Is this “intended” firmware behaviour or an error – or can it be changed in a future release if Fix ESS agree and there's no other reason why not?

Martin Rimmer at Fox ESS won't, of course, advise on external remote control but I don't think that's the underlying issue and recommended I post here/ask @will for advice too...

I think to start, mode scheduler and setting the remote power register as you are, is doing exactly the same thing (mode scheduler sets power, timeout and enable registers as well) - it's the inverter that is then making the decisions about what source of power to use and setting the limits.

It's been a long time but I recall something similar happening on the H1-G2 when it first came out, the firmware was reducing PV input as the battery throttled back to the point that when fully charged, PV was fully disabled and it took quite some time before Fox acknowledged it and corrected it (in firmware).

If it's happening on mode scheduler you can remove any third party application from influencing it, in that you would not expect PV to be limited when using the force charging schedule because the battery was full - obviously if Fox come back and say that's the way it is, that's a different thing but on my old H1 (gen 1) this does not happen, perhaps others can comment on that.

The only comment i'd make on your register settings, you are writing 60536 to 44002 which sets the maximum remote active power register, 60536 is (-5000 watts) and you have a 6kW inverter so it should really be set to 59536 (-6000 watts). That said I don't think it will make much of a difference to the problem here as it's never achieving max power and being throttled although on a warm day if your batteries could accept it, you might want to charge at full power.

Thanks Dave - I previously had an H1-5.0-E-G2 which was "bricked" by a Fox ESS firmware update and replaced under warranty - they gave me a 6.0 as replacement

I did have the same issue on the older G2 which as you say was, I'm sure, fixed over time but I had a huge struggle to get Fox ESS to recognise the issue when it happened before and now they've regressed it into the new WL variants.....

Good spot re the HA setting - that's a legacy of my old inverter too - I'll update it as you suggest!

I just spent some time reading back through the Force Charge/Discharge discussions on Nathan's integration - interestingly the H1 (Gen1) used to have the same problem and it looks like Antony spent ages trying to work out how to make the inverter blend PV and grid power to maximise PV.

That integration on each poll cycle (~ every 10 seconds) looks at what power the battery is capable of accepting (a modbus register called pwr_limit_bat_up), how much PV is available, the battery soc and maxsoc setting, it then backs off the active power amount to match the required demand less a 50 watt margin, otherwise it notes that PV is clipped (sound familiar) when the battery is starting to throttle.

Ironically shortly after that the H1 (G1) was fixed to blend the power correctly, but the 'bug' was then transferred to the G2 until it was fixed there.

The problem is there are now so many different inverter models, all exposing different modbus register maps where some seemingly work the way you would expect, and others do what you are seeing.

If the notes are still valid, it seems reasonable that if you see your battery charge power limit is lower than the requested power amount (5000 watts), you should reduce the active power value to just below (~100 watts) the battery power limit and the PV won't be clipped - obviously this will take some work to calculate but in the absence of a fix it's worth trying ?

Thanks Dave - glad it's not just me! Unfortunately that level of HA logic and coding is a bit beyond me....

Perhaps Will can push Fox ESS to sort the H1-G2-WL firmware??

Jim, just chatting with Tony about what you are looking to do, and I had a proper read through what you posted, the one bit I missed was you wanting it to export excess power when the charge completes which is in effect normal Self Use workmode.

I don’t recall the old G2 doing that?, my gen 1 H1 doesn’t but at least the PV continues to power house load after a Force Charging and the battery is full.
So that actually sounds like what you want your HA to do is have an automation that detects the battery being in a Force Charge mode and being fully charged (or nearing full) and then switch the inverter workmode back to Self Use to use PV again as normal, that should be do-able.

I already have an automation to stop force charge once SoC hits 100% - It’s only while actually force charging that the PV generation is clipped to the BMS max charge level……

As soon as I get chance i’ll test my H1 to see what it does when force charging and battery limit is below PV, but I think it might be quite a few weeks before I get enough PV in the North West for that