Generator change over switch , where existing PV

p.sheridan · 14-02-2026 08:29PM #1

hi. Sorry , I could be asking this in the completely wrong place.
I have 12 panels. Solos inverter. No battery storage. No EV.
I want to fit a changeover switch so as I can run a generator during outages. I know the solar cuts off during an outage.
does the fitting of the changeover interfere with the existing wiring of the solar, like will the electricians have to change any of what the solar guys have wired , or will the changeover switch be just a straight forward seperate install ? Thank you.

Chiarrai92 · 14-02-2026 11:47PM

yes generally the inverter and solar system has to be turned off when the generator is running..

With the generator on.. the inverter thinks it's connected to the grid and may try to export.. you don't want that

chiefwiggum · 14-02-2026 11:59PM

I have only done this in the last couple of months.

I turned off trip switch to Pv system and start generator..works great

graememk · 14-02-2026 09:08PM

https://www.boards.ie/discussion/2058432645/generator-change-over-switch-where-existing-pv

Should be fine, although part of the changeover procedure will likely be to turn off the inverter.

davebuck · 14-02-2026 10:18PM

https://www.boards.ie/discussion/comment/124236818#Comment_124236818

Can any inverters stay online with a generator if the changeover switch prevents any feed back to the ESB grid?

graememk · 14-02-2026 10:42PM

https://www.boards.ie/discussion/comment/124237057#Comment_124237057

Really depends on the generator but generally no, inverter will see it as the grid and if the house isn't using all the power it will be back fed power. I dare say most don't like being fed power!

Some inverters now have a generator port so if you had batteries the generator is used in tandem with the solar/charge batteries so the generator doesn't have to run 24/7.

Changeover is run to the load or backup port on the inverter.

p.sheridan · 14-02-2026 11:27PM

ok. So , even though the inverter shuts off, with the power cut. The changeover switch system will need to turn off the inverter so as it doesn’t think the electric is back on. Am I getting it right ?

graememk · 14-02-2026 11:56PM

https://www.boards.ie/discussion/comment/124237307#Comment_124237307

Expensive noises 😂

Chiarrai92 · 15-02-2026 01:16AM

https://www.boards.ie/discussion/comment/124237262#Comment_124237262

No.. the AC supply to the inverter will need to be turned off separately. Can't speak for your system but but I have a switch between the inverter and the fireman switches this also needs to be turned off .

Basically everything needs to be turned off at the solar system itself .. before the generator is turned on.

The changeover switch is between your consumer box and meter.. it doesn't turn off your solar set up. That has to be done separately.

pureza · 22-02-2026 12:01PM

@graememk Have you any knowledge of these Sigenergy systems that configure your system to be a ups during a grid outage

It Probably could do with a new thread but I notice a few Irish solar installers are doing them now ? I wonder do they marry into existing Solis inverter kit or would you have to change out the whole lot?

We have 20kw batteriy storage and 15kwh in solar panels so in theory could make an almost off grid or prolonged outage solution here?

https://www.sigenergy.com/en/products/gateway

graememk · 22-02-2026 01:51PM

Don't know anything about sigenergy but as it's a closed system, the party line will likely be "an unsupported configuration" or something

The solis can run a changeover switch. Question is do you need ups level backup or is a changeover switch enough. How often do you get outages?

pureza · 22-02-2026 02:47PM

https://www.boards.ie/discussion/comment/124256261#Comment_124256261

Not that often

But I wanted to put a solution in,as the current back up is a tractor pto driven generator

It’s fine and does the job but involves 20 to 30 mins out in the cold and wet to set up each time

I might sell it

The other option is putting a few essential trip switches on the house board on a change over to an anker solix f3800 ,a battery powered rechargeable generator you can have indoors and is portable?

graememk · 22-02-2026 03:52PM

https://www.boards.ie/discussion/comment/124256389#Comment_124256389

What sort of demand are you looking at when running on backup?

The solis possibly will be able to do the same job as the generator.

You could upgrade the solis to the S6 version.

That one has a generator input, so you only need to connect the generator when the battery is low. And use the generator to charge the battery, and stop it when not needed.

SodiumCooled · 22-02-2026 03:55PM

https://www.boards.ie/discussion/comment/124237152#Comment_124237152

My AlphaEss invertor and battery setup has a setting in the app for generator control. I haven’t fully got to the the bottom of how it operates but the assumption would be it prevents back feeding.

I have a dual change over switch setup. Main change over between ESB and off-grid and then off grid output goes to a second changeover which switches between solar or generator. Even the electrician for the solar company doing the install commented that when switched to generator the solar would also active as it would energise the fireman switch and I could change the battery off the generator. I didn’t question him any further on it though and I probably should.

Not sure I’d charge it with my current non-inverter generator though I’ve run plenty of so called delicate loads on it before during storm outage last year without issue. I may upgrade to an inverter generator in future and in this case I would definitely like to be able to charge the battery. The other thing that would interest me is using V2L to change the battery where again preventing back feeding would be essential - I didn’t even have an EV currently though.

graememk · 22-02-2026 04:05PM

V2L is essentially a generator anyway.

Can't comment on the alphaESS, only really the deye/Sunsynk with any certainty.

The new solis hardware looks identical to the Sunsynk/deye, only difference is the screen.

There is 3 inputs on the inverter grid, gen, and load.

The inverter has relays on all 3 connections, so if it's going to try and charge from the generator it will disconnect from the grid (if not already disconnected) and then synchronise with the generator before connecting to it.

SodiumCooled · 22-02-2026 08:47PM

https://www.boards.ie/discussion/comment/124256636#Comment_124256636

I’m struggling to find concrete info but I do see it suggested that the generator control on the alpha is a purely software setting and that there isn’t any separate connection for a generator. My sort of hope/assumption would be that this setting makes the inverter charge the battery and not supply any house loads but more digging/reading required.

pureza · 22-02-2026 09:46PM

with a generator connected in the appropriate mode wouldn’t the theory be that the house would be supplied by the batteries,at the same time as the generator is charging the batteries whilst also when in that mode the grid is cut off ? The inverter couldn’t be certified to do anything else?

@graememk to answer your question to me upthread,having a compatible Solis inverter would be ideal,I have 2 inverters though , would both have to be capable of island mode?

graememk · 22-02-2026 10:13PM

https://www.boards.ie/discussion/comment/124257805#Comment_124257805

do you have a string inverter and a hybrid inverter? - if that is the case yes the string inverter will see the power generated by the hybrid as the new grid and work fine. Although the older solis, if there is nowhere to put the power (eg battery full), does shutdown the backup output completely.

deye /sunsynk just shifts the frequncy to 52 hz and shuts down the string inverter to curb the excess production.

In a power outage, with the grid isolated and the generator connected, the generator then becomes the new grid, but the inverter will not allow any power to be back fed into the generator. Its becomes its own grid. when the batteries are being charged, Everything will be running off the generator, you can set generator limits, so if the generator reaches its max, the batteries will stop charging, or even start discharging to keep the generator under its limit if the house decides to pull more than expected

idc · 23-02-2026 11:56AM

I don't have a generator but have a hybrid inverter with 10kWh battery. Connected to this is a 1 kW string inverter. Similar to discussion about about generator + inverter. During power outage (in summer) both inverters will charge battery if house load already covered and have excess.
Where this is similar to a generator is the scenario whereby battery is full and the string inverter is still generating power. The hybrid inverter can't handle that excess and basically goes into an error state and stops work altogether. For this use case only solution is to turn off the 1kw inverter

Generator change over switch , where existing PV

Best Answers

Answers