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Off-grid All-In-One system in detached garage fed by the house from GRID in UK

Palomacat

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Joined
Jan 9, 2022
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5
Hi guys.
Planning to install solar panels on the garage roof with All in One system() + battery installed in the garage.
At the moment garage sub panel is fed from the house which is connected to the main grid.
The plan is to feed the garage with solar power and send the excess power to the house and/or store it in the battery.
At the moment I am not worried about solar as backup, when the grid goes down, as it never happens.
The purpose of this installation is to cut the energy bill and charge EV vehicle (future installation), from solar when possible.
The planned topology is as follows:
Solar PV ---->Inverter----->Garage Sub Panel------>House Main Panel
Can somebody advise me from their own experience or expertise if this is even possible without running extra cabling between house and garage and rewiring the Main panel into critical loads etc?
Any wiring topologies and diagrams are more than welcome.
Thank you
 
UK uses somewhat different wiring than we do here in the states, but we would need to know how your garage is currently connected to the house wiring to answer this.
Does it have around a 60A feed? Is it just connected for lights and outlets?
What power do you have in there now?
 
The garage sub-panel is 100A rated. Single twin and earth cable between the house and the garage, either 6 or 10mm2, can not tell for sure. The garage is connected to a 32Amp breaker in the main panel.
 
The garage sub-panel is 100A rated. Single twin and earth cable between the house and the garage, either 6 or 10mm2, can not tell for sure. The garage is connected to a 32Amp breaker in the main panel.
Probably 6mm2 if on a 32A breaker. 10 would allow 45 or so depending on insulation rating.
 
If you are planning to backfeed the grid, you should be able to tie the solar to the garage as is.
If you want it off grid, than the garage feeder would need to be on a transfer switch of one type or another.
 
@Supervstech Thank you for looking into this. My initial plan was to install a Growatt grid-tie inverter and I know that at the present setup it would work. However, due to fact that I would not get paid for any excess solar power, I am considering an off-grid alternative and related costs. Would your proposed transfer switch mean that I do not need extra cabling between the house and the garage? The main confusion for me here is how AC in AC out works on the All in One unit. Does AC intakes power just for the inverter itself? Then the same cable between the house and garage would be used to pull power from the house and backfeed from the inverter? The unit I am considering is this: https://bit.ly/3riKKB5
 
Transfer switch can use the existing wiring, it all depends on what gets critical use and what is transferred.
If garage is considered source, and all solar is on the garage panel, the house feeder can be used.


Inverter settings usually configure ac input functions.
 
Wow @Palomacat . I've come here with exactly the same question as you! I'm also setting up a Solar / Battery / Hybrid combo in the UK. I don't want to sell back to the grid (not worth it) but looking to charge batteries with cheap off-peak and daytime solar, use those batteries as main power and supplement this with the Grid whenever I use more than the hybrid inverter can produce.

I've got a 100A cable running from the mains distribution to an outbuilding where the setup will live.

So, as I understand it, I need Grid Tie (note the one you suggested above is off-grid only). I then have the inverter output to the mains distribution via the 100A cable but at the same time, it's using this as the mains in. So in simple terms, I just need to connect both AC in and AC out on the inverter to the same mains cable running to the distribution box.

That's my thinking anyway, just hoping somebody here can tell me if I'm missing anything?

My current leading contender for the job is... https://www.aliexpress.com/item/1005002320046188.html?spm=a2g0o.cart.0.0.45e53c00AOAhad&mp=1

It has both on and off-grid capability, and a limiter function to prevent power from being sent to the grid.

On the manufacturer's site, there is a newer version with higher power output (prefer to not max these things if I can avoid it) but I can't find it for sale anywhere. waiting for a response from them... https://www.soropower.com/7/5.5kw-8...er-with-two-mppt-solar-charge-controller.html
 
Wow @Palomacat . I've come here with exactly the same question as you! I'm also setting up a Solar / Battery / Hybrid combo in the UK. I don't want to sell back to the grid (not worth it) but looking to charge batteries with cheap off-peak and daytime solar, use those batteries as main power and supplement this with the Grid whenever I use more than the hybrid inverter can produce.

I've got a 100A cable running from the mains distribution to an outbuilding where the setup will live.

So, as I understand it, I need Grid Tie (note the one you suggested above is off-grid only). I then have the inverter output to the mains distribution via the 100A cable but at the same time, it's using this as the mains in. So in simple terms, I just need to connect both AC in and AC out on the inverter to the same mains cable running to the distribution box.

That's my thinking anyway, just hoping somebody here can tell me if I'm missing anything?

My current leading contender for the job is... https://www.aliexpress.com/item/1005002320046188.html?spm=a2g0o.cart.0.0.45e53c00AOAhad&mp=1

It has both on and off-grid capability, and a limiter function to prevent power from being sent to the grid.

On the manufacturer's site, there is a newer version with higher power output (prefer to not max these things if I can avoid it) but I can't find it for sale anywhere. waiting for a response from them... https://www.soropower.com/7/5.5kw-8...er-with-two-mppt-solar-charge-controller.html
Did you manage to install your system as you described?

I am looking to do the same as you describe. I have a single cable off the main fuse box supplying lights and a dual 13a socket (i presume its is 32amp rated, its certainly a meaty sized cable) . I was going to change current socket for a small CU and wire the inverter GRID and LOAD cables into this with a isolator switch.

Really keen to avoid any extra cables or messing with the main fusebox as its all tidy within the walls.

many thanks
 
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