dualling inverters

[openspaceman]

Leading on from Norabatty's thread and the link to the guy in Scotland with Sunsync inverter; can anyone answer a hypothetical query? In the unlikely case were my FIT inverter to fail and I replaced it with a 3.6kW Sunsync inverter and then added a second 3.6 inverter on another circuit it shouldn't affect my FIT.

Could the battery then only be on the non FIT inverter, so it might be charged from the grid?

I have had no problems with my Victron battery charger but I take the point the Victron Multiplus II does seem to need lots of extras whereas the Sunsync works just as it is.

[nowty]

Could the battery then only be on the non FIT inverter, so it might be charged from the grid?

That is the easiest option but you can agree with your FIT provider a change to a bi-directional generation meter so it is possible to have grid charge storage on the FIT side, thus only requiring a single hybrid inverter.

https://www.ofgem.gov.uk/sites/default/ ... 20v6.1.pdf

https://midsummerwholesale.co.uk/buy/me ... onal-meter

[openspaceman]

Thanks for that Nowty, so the FIT provider subtracts any grid charge from the total that goes through the meter to give the solar PV generated electricity?

My situation is that I have my extra panels just charging my battery and if I ever get away from deemed export I will need a second inverter for the surplus from them. Currently 1800W installed capacity on top of FIT but adding 600W this week and a further ~1500W planned. Octopus are being very slow moving me to am export tariff from deemed, my current FIT provider may have something to do with this.

[nowty]

Thanks for that Nowty, so the FIT provider subtracts any grid charge from the total that goes through the meter to give the solar PV generated electricity?

The bi-generation meter does the subtraction so you would only give the FIT provider the net generation figure.

[resybaby]

In the unlikely case were my FIT inverter to fail and I replaced it with a 3.6kW Sunsync inverter and then added a second 3.6 inverter on another circuit it shouldn't affect my FIT.

Could the battery then only be on the non FIT inverter, so it might be charged from the grid?

I dont know if im going to be helping here (hope so) as i have a similarish system/dilema/risk, or confusing things/grabbing the wrong end of your stick, so bear with me incase my experiences are helpful.

My existing Details are:-
SMA sunny boy on one set of 4kw panels, FIT tariff and generation meter on deemed export. Similar to you.
Separate Sunsynk 3.6kw ecco hydrid on 5.45kw of panels with bidirection generation meter thats ignored as i dont export.
35kw of storage connected to Sunsynk only for discharge/charging. As per your question above.

All i can add really is that the output from my SMA FIT invertor can be 'captured' and fed into the batteries that are soley connected to my Sunsynk invertor. I run like this most days during periods of lower pv generation. To a point.
The Sunsynk invertor has an option in the AUX menus called 'micro invertors'. see photo. This allows you to 'capture' the non connected FIT invertors output and send that to the battery - i suppose the clues in the name, as a 'microinvertor'.
However. My experience and understanding is it will only add upto the sunsynks maximum charge rate of 4.8kwh.
That is the maximum combined amount it will send the battery. If my total PV exceeds this level going to battery/load then my Sunsynk system ramps down, leaving my FIT system running at maximum still.

The next photo from my sunsynk shows this setting in operation. i.e. my sunsynk is producing 509watts from its own panels. Whilst the FIT systems SMA is adding 510watts (quite why it shows it as a UPS i havent a clue, you would think it would show this number under the AUX feed).
Both of these figures can clearly be being seen as going to my battery storage at the combined rate of 912watts. So although my FIT isnt connected to the batteries, it can be done so by the sunsynk settings themselves.

Hope i've explained that well enough

[AGT]

Hi Resybaby,

Can I ask do ou just require 1 CT on the hybrid inverter for this set up?

Sounds like it’s the way I want mine set up when I get around to it?

[resybaby]

Hi Resybaby,

Can I ask do ou just require 1 CT on the hybrid inverter for this set up?

Sounds like it’s the way I want mine set up when I get around to it?

Yes AGT, i just have the one CT connected to the Sunsynk invertor only.

I do have a Marlec afterwards with its own CT, but thats nothing to do with neither invertor so can be ignored.

[AGT]

Thanks, much appreciated, just planning cable routes as
My inverters are not close to each other!

[openspaceman]

I dont know if im going to be helping here (hope so) as i have a similarish system/dilema/risk, or confusing things/grabbing the wrong end of your stick, so bear with me incase my experiences are helpful.

Thanks for that and the set up does look simple enough. I see that the sunsyncs use frequency increase to shut down??

Komando pointed out my Solarmax inverter can be configured to do this but it's a bit beyond me.

I too have a nominal 4kW on FIT and have also added about 1800W DC battery charging but this is curtailed every day in the summer. I have today added 600W to a shed roof and this will charge a portable power station in the shed with a 3kWh battery.

All the time I am on deemed export all well and good but if Octopus ever get me an export MPAN and I am removed from deemed export I will need to combine the additions and a planned further ~1kW of PV, on the much strengthened shed roof, with a second inverter to benefit from exports and prevent curtailing.