Solis S5 / Fox Battery not discharging

[Triff]

Hi

I have a complicated system (?) as I dont have roof space for 12 panels so they have been split over the garage roof and house roof. Each string on panels having a dedicated Solis S5 invertor and Fox 5200 battery (therefore I have 2 independant but connected systems - one on garage roof and one on house roof). Im told that the garage system will feed power back to the house circuit as needed via the AC cable but the batteries for each string are independant (I understand and accept the compromise or splitting the batteries out and avoiding a DC feed being run from the garage back to the house and having a single invertor and battery set up)

The set up on the house roof works fine and the battery icon on the Solis App is purple, the battery charges from PV and grid fine and discharges fine. Job done.

The garage string will charge from the grid but wont discharge on demand. The icon on the app for the battery is grey. I have checked settings on both invertors and they appear the same. The only way I can get the battery to discharge is to set up the invertor to discharge to grid and drain the battery to the grid ... which shows that the invertor can at least drain the battery...but clearly not how its needed to work...i.e. to support demand from the house.

From a App perspective I have 2 seperate system accounts with each invertor talking to my wifi independantly via a dongle

any thoughts anyone? does anyone know the significance of the battery icon colours?

thanks in advance

 

[SeaGal]

Welcome - sorry, only just spotted your posting.

I only have a single Solis + battery, so this is a bit of a guess.. but I suspect that the issue is that Solis is not designed inherently to interwork in the manner that you have connected them.

I am assuming that you have two Acrel power meters, one feeding each Solis and their CT clamps are both connected around the live supply from the grid - is that correct?

If so, they may well both be fighting to balance house usage and hence only one will attempt to use battery to discharge.

Without going down the route of MITM software to manually control each Solis (as for example @peufeu has done) I'd try the following...

Move the battery from the garage inverter to the house inverter to simplify your 'complicated' system. That will mean that only one inverter has to balance house demand with battery discharge.

The garage inverter will then only act as a solar PV microgenerator. From what I understand from other's postings on here, with such a configuration your house Solis will charge the batteries if there is _any_ export to grid being detected (up to the point that the battery is full, obviously). And then discharge batteries if you are using more energy than the sun is providing.

To make that clearer with an example or three...
House PV = 2kW, Garage PV = 1kW, House usage = 500W. This would result in the House Solis charging batteries at 2500W.
House PV = 1kW, Garage PV = 800W, House usage = 3000W. This would result in the House Solis discharging batteries at 2200W.
Nighttime.. House PV = 0kW, Garage PV = 0kW, House usage = 400W. This would result in the House Solis discharging batteries at 400W.

 

[peufeu]

From what I understand from other's postings on here, with such a configuration your house Solis will charge the batteries if there is _any_ export to grid being detected (up to the point that the battery is full, obviously). And then discharge batteries if you are using more energy than the sun is providing.

Yes this is the simplest.

Put all batteries on one inverter.

Inverter without batteries: doesn't need meter, set to export all power. Maybe set to turn off at night. In fact you can sell the S5 hybrid and replace it with a cheaper grid-tied inverter, or you can keep two identical inverters for redundancy. Currently I'm still using 1 Solis S5 hybrid + 1 Fronius Primo non hybrid.

Inverter with batteries: meter placement "grid" to detect export from other inverter, self-use mode, set maximum allowed export to the maximum the other will export*, and you're good to go. If it detects exported power from the other inverter, it will charge the batteries.

* if you don't do that it will trigger safe mode if it sees the other export more power than is allowed.

 

[shavermcspud]

The current range of Solis Hybrid RHI inverters cannot be run in parallel on a single phase supply

 

[SeaGal]

The current range of Solis Hybrid RHI inverters cannot be run in parallel on a single phase supply

Can you clarify what you mean - I am planning to go down a dual Solis route shortly?

From my understanding, there is no inherent comms between RHI or EH1 inverters for parallel operation (although that is a feature of the new S6-EH PRO models). Hence it is not possible for two RHI's to each have a battery and manage discharge of house load from 2 sources. Nor is it possible to parallel the AC backup from 2 different Solis without destroying the inverters.

But, if one Solis RHI is operating as a PV-only grid-tied inverter, without export power limitation and the other RHI is operating as with PV and battery, then they can both be connected in parallel on their AC-grid connection on a single phase. Furthermore if the RHI with battery detects power being exported to grid (i.e. from the PV-only RHI) it will charge batteries from the excess power generated from the PV-only RHI so, as far as possible to achieve 0W import/export.

 

[shavermcspud]

Can you clarify what you mean - I am planning to go down a dual Solis route shortly?

From my understanding, there is no inherent comms between RHI or EH1 inverters for parallel operation (although that is a feature of the new S6-EH PRO models). Hence it is not possible for two RHI's to each have a battery and manage discharge of house load from 2 sources. Nor is it possible to parallel the AC backup from 2 different Solis without destroying the inverters.

But, if one Solis RHI is operating as a PV-only grid-tied inverter, without export power limitation and the other RHI is operating as with PV and battery, then they can both be connected in parallel on their AC-grid connection on a single phase. Furthermore if the RHI with battery detects power being exported to grid (i.e. from the PV-only RHI) it will charge batteries from the excess power generated from the PV-only RHI so, as far as possible to achieve 0W import/export.

Exactly as you have just described