Moving all circuits to an of grid inverter

[ns31]

Hi all, I'm looking into off grid all in one inverters with batteries but I'm wondering how these power all circuits in the CU from the mains feed.

Specifically how does the AC in work? Do you run the main house supply into the inverter AC in, and then the AC out to the consumer unit? So there's a new step between the main feed and the CU?

Therefore the inverter would use battery and PV power, but draw from the mains when they're empty?

I can't find any videos of a mains feed into the off grid inverter. My house has a breaker between the mains feed and CU, is assume this breaker would feed into an all in one inverter

 

[DIYrich]

"Off grid" is usually no grid connection. But they can be connected like a grid connected inverter like you have described. The difference then is that the off grid inverter does not have the ability to send excess power to the grid. The on grid inverter will also have more modes to determine when to use what power source.

 

[LeoThomson]

Think of your solar panels, batteries and inverter as a generator. But instead of fossil fuels, it uses sunlight to generate electricity, instead of a fuel tank it uses batteries. Everything else on the AC side is essentially the same.

I would not feed back into the grid, the grid in some parts of the world can't cope with all the electricity generated by solar during the summer months and this will only get worse. So I would suggest you install a sub panel that feeds some circuits from your inverter and you could have the invert charge your batteries from the grid when needed. The number of circuits depends on your needs and usage profile.

There are a whole load of advantages and disadvantages for any system, but only you can decide what works for you. For me this is an expensive (US$4000) hobby that has been a lot of fun and that I expect will eventually pay for itself.

 

[DIYrich]

I would not feed back into the grid, the grid in some parts of the world can't cope with all the electricity generated by solar during the summer months and this will only get worse.

Depends upon the utility. In my area they pay you to feed back the grid between 3pm-8pm. Similar to TOU pricing. Net metering plus bonus. If severe weather is predicted, you save your power for possible grid down.

This actually helps the grid, not destabilize it.

 

[ns31]

Cheers all, so I understand what off-grid does etc, I'm just wondering about the installation technique, is it normal that an inverter will sit in between the mains feed and your consumer unit? This is the relevant place? As this enables battery/PV usage until it runs out, and then AC in takes over

 

[hwy17]

Ideally that's where'd you want it, but there are many practical reasons result in the majority of us not placing them between grid and main panel / CU.

I don't know what kind of things people do in the UK. Mine's going between a main panel and a subpanel.

 

[DIYrich]

Various wiring options start on page 47:

https://www.sol-ark.com/wp-content/uploads/15K-2P_Manual.pdf

Sub-panel variations start on page 46:

https://www.sol-ark.com/wp-content/uploads/12K-2P-N_Manual.pdf

 

[SamDeleted]

Hi all, I'm looking into off grid all in one inverters with batteries but I'm wondering how these power all circuits in the CU from the mains feed.

Specifically how does the AC in work? Do you run the main house supply into the inverter AC in, and then the AC out to the consumer unit? So there's a new step between the main feed and the CU?

Therefore the inverter would use battery and PV power, but draw from the mains when they're empty?

I can't find any videos of a mains feed into the off grid inverter. My house has a breaker between the mains feed and CU, is assume this breaker would feed into an all in one inverter

Yes Hybrid/ all in one inverters will decide how much power to take from the grid , you can set priorities,

SBU or SUB. ,

Solar, battery, utility

Solar, utility, battery


Really it depends just how large a off grid inverter you are buying . If you want to install between the meter box and the CU , it needs to be big enough to handle all house hold loads at once


We've got an 11kw electric shower, 8kw cooker. If just those two items was turn on full, that's be 19kw draw . Too big for almost any AIO/hybrid inverter. You would need multiple in parallel ( and a bank loan most probably ? )

 

[SamDeleted]

The simplest solution is to install your off grid solar set up completely separate from current wiring and run extension leads to required items, lamps, freezers, toaster, kettle etc etc


The only connection to the national grid would be the AC input on the hybrid inverter, it would draw on the mains as needed if there's no solar and your batteries are low


You're on sketchy legal ground doing your own install in the UK , you SHOULD have a sparky come do it . But it's no skin off my back.

 

[dougbert]

I added a new panel (#2) that became my Critical Loads Panel, which supplies MOST of my house, down stream from original grid panel #1

for schematics look at Post #1 in my build thread. Link is in my Signature below

 

[ns31]

Really it depends just how large a off grid inverter you are buying . If you want to install between the meter box and the CU , it needs to be big enough to handle all house hold loads at once

This is a good point, I suppose the amount of circuits you can run is based upon the output of the inverter. I'm considering 8-11kw but even this might not handle everything in the house, I'll do the maths with this in mind.

You're on sketchy legal ground doing your own install in the UK , you SHOULD have a sparky come do it . But it's no skin off my back

Just doing research at the moment, I'm undertaking my domestic spark certifications so I can handle domestic electrics legally. That being said, I wouldn't trust half the certified sparks out there sadly!

 

[SamDeleted]

Just doing research at the moment, I'm undertaking my domestic spark certifications so I can handle domestic electrics legally. That being said, I wouldn't trust half the certified sparks out there sadly!

You can come do mine then , mates rates cause I helped you out ?

 

[SamDeleted]

@ns31

EDECOA Solar Hybrid Inverters 1600W 12V 240V Off Grid Sine MPPT 80A 55-450VDC | eBay

EDECOA Solar hybrid Inverter. Pure Sine Wave 12V 1600W MPPT 80A. 1x Hybrid Inverter 12V 1600W. Pure sine wave inverter (THD <3%). OFF grid: the inverter does not feed power into the grid. ALL-in-One Hybrid.

www.ebay.co.uk

These are cheap if you fancied playing with a small one before the big install, very much the same settings and set up as most all hybrid inverters, just smaller

Great little thing, might be worth a look

 

[Craig]

Cheers all, so I understand what off-grid does etc, I'm just wondering about the installation technique, is it normal that an inverter will sit in between the mains feed and your consumer unit? This is the relevant place? As this enables battery/PV usage until it runs out, and then AC in takes over

This is exactly I do it at my California residence. I have my inverter charger set to only use the grid when the batteries are below a certain level then as soon a they rise again through solar charging the grid turns off. so yes inverter charger between grid and house panel. make sure you follow all local codes of course.

 

[ns31]

This is exactly I do it at my California residence. I have my inverter charger set to only use the grid when the batteries are below a certain level then as soon a they rise again through solar charging the grid turns off. so yes inverter charger between grid and house panel. make sure you follow all local codes of course.

Thanks, so does this place a restriction on the house mains supply? So if we had no inverter, the limit is whatever the feed in is, or the breaker thats on the mains (usually 80 - 100a) - but by introducing an inverter before the CU we'd now be limited to the kwh of the inverter?

It looks like 11kw inverters have an ac output of around 50a. So by adding an inverter between the mains supply and our CU, we immediately step down our mains from 80-100a, to 50a?

 

[Craig]

Yes this is the problem having an inverter or set of inverters large enough to match the grid is very expensive. I said this is exactly what I do but I do not do it on all my circuits. if you want a hybrid system you would need maybe a second panel with only the circuits that you power from solar.

 

[ns31]

Yes this is the problem having an inverter or set of inverters large enough to match the grid is very expensive. I said this is exactly what I do but I do not do it on all my circuits. if you want a hybrid system you would need maybe a second panel with only the circuits that you power from solar

Makes sense. Looks like 2 inverters in parallel would just about match the grid, so around £2000 worth. Costly, but not too bad given the overall costs I suppose

 

[LeoThomson]

Depends upon the utility. In my area they pay you to feed back the grid between 3pm-8pm. Similar to TOU pricing. Net metering plus bonus. If severe weather is predicted, you save your power for possible grid down.

This actually helps the grid, not destabilize it.

Around those times you are absolute right. But there have been times where between 12 and 3, some homes have not been able to supply, cutting on their "income".