FoxESS Community - Owners & Installers Forum

Hope you guys can help, been trying to research in forum but was not able to find any clue, also called the installer who simply said.. not possible but I won't give up easily. Back to the question

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I have a FoxESS AC1-3.0-E used as main inverter with battery pack too. All solar panels are connected with power optimizer from Huawei to a Huawei inverter that is 100% dedicated to solar power generation so panels are not connected to the FoxESS but thru the Huawei that basically is seen as an input (see APP screenshot).

Both Inverters are connected to the grid direcly and we have sensing switch that basically disconnect the grid when this down to enable the use of the EPS and not route back power to the grid.

The problem that I have is that once grid is off the Huawei is disconnected so I can basically only use the battery, quite a pain when blackout happens during the day. They told me that with EPS mode the extenal "Huawei" source will always be disconnected and the FOXESS inverter won't work in EPS mode accepting the Huawei as an input but seems to me nonsense so different wiring connection (so the Huawei powered post Foxess and not directly to the grid) or SW configuration may do the job.
Any idea or recommendation I can push back to the installer?

Thanks for your feedback

Both the Huawei and Fox inverters are grid tied inverters, when the grid fails the Huawei will shut down as will the Fox inverter, but the Fox will allow operation on it's EPS output which is distinct from the grid input (and as you have said you have to remove any link to grid when 'islanding' in this mode.)

The Huawei cannot operate as it has no grid volts to harmonise with and the Fox AC1 inverter in EPS has no way to accept the power from the Huawei as the grid side is shutdown. If you were to connect the Huawei to the EPS output it won't work, it is not designed for that and it will trip the inverter.

The only solution would be to ditch the Huawei, replace the AC1 with an H1 (hybrid) and the DC from the PV panels connected directly to the hybrids PV inputs. The hybrid is unique in the it blends the DC from the battery and the PV on a DC VBus and that is then used to power the EPS circuits.

Dave thanks for very comprehensive explanation.
So even if I find a way to power up the Huawei while in EPS mode the FoxEss won't be able to accept this so it won't work.
If quite frustrating to be off grids with sun shining and limit your consumption to the battery..

The only reason I got this system installed like this was (I was told) due to the optimizer of Huawei that expect to talk to the Huawei inverter.
If I get rid of the Huawai and connect panels to the FoxEss I won't be able to take advantage (?? any??).
THanks again

Yes that’s it, it’s a good solution when on-grid, but for an EPS system you would need the solar and batteries on the same system so that it can blend them as part of its power source, I know that Huawei make hybrids, is there any scope to add batteries to your solar inverter ?.