Connecting solar to house, without connecting to grid

Cmorar

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Joined
Jul 8, 2021
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10
I’m curious on if there is a method to connect my inverter to my houses wiring without actually connecting to the utility grid so I don’t have to deal with the regulations or fees. I’m looking at an MPP or Growatt unit to make the process simpler, but I’m not sure what I would wanna connect and where. I assume that it’s possible to connect your houses wiring without connecting to the grid but after googling and looking through the forum I haven’t been able to find anything I could understand.
 

pvdude

Solar Addict
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Feb 8, 2021
Messages
243
I used a Square-D manual transfer switch.
Found a used one on ebay.
It connects either:
- grid to house
or
- solar to house

Very safe, it is mechanically impossible to make incorrect switching.
transferswitchlaundryroom.png
 

Cmorar

New Member
Joined
Jul 8, 2021
Messages
10
I used a Square-D manual transfer switch.
Found a used one on ebay.
It connects either:
- grid to house
or
- solar to house

Very safe, it is mechanically impossible to make incorrect switching.
View attachment 55701
i see! So when I want to connect to one or the other I flip a switch or something along those lines?
 

OffGridInTheCity

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Joined
May 23, 2021
Messages
456
Location
Southern Oregon
I use several ATSs (automatic transfer switchs) to connect my off-grid solar to the house. When the PV -> battery charges up enough to turn on the Inverter - the Inverter power flips the ATSs from grid to inverter. When the batteries run down and the inverter goes off, the ATSs automatically switch back to grid.

At the main panel, I have a 50a@240v ATS + a 10 circuit MTS (manual transfer switch) combination for general circuits / load control. The MTS let's me choose which circuits are 100% grid if I need to lesson the max load on the inverter. A dedicated 12,0000w AIMS inverter feeds this ATS - which is 50a@240v.
1625940965206.png
 

Cmorar

New Member
Joined
Jul 8, 2021
Messages
10
I use several ATSs (automatic transfer switchs) to connect my off-grid solar to the house. When the PV -> battery charges up enough to turn on the Inverter - the Inverter power flips the ATSs from grid to inverter. When the batteries run down and the inverter goes off, the ATSs automatically switch back to grid.

At the main panel, I have a 50a@240v ATS + a 10 circuit MTS (manual transfer switch) combination for general circuits / load control. The MTS let's me choose which circuits are 100% grid if I need to lesson the max load on the inverter. A dedicated 12,0000w AIMS inverter feeds this ATS - which is 50a@240v.
View attachment 55702
This looks like a setup that is more in line with what I want to do, thank for the pic and explanation!
 

Jamie.sanders

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Joined
Dec 1, 2019
Messages
100
I use several ATSs (automatic transfer switchs) to connect my off-grid solar to the house. When the PV -> battery charges up enough to turn on the Inverter - the Inverter power flips the ATSs from grid to inverter. When the batteries run down and the inverter goes off, the ATSs automatically switch back to grid.

At the main panel, I have a 50a@240v ATS + a 10 circuit MTS (manual transfer switch) combination for general circuits / load control. The MTS let's me choose which circuits are 100% grid if I need to lesson the max load on the inverter. A dedicated 12,0000w AIMS inverter feeds this ATS - which is 50a@
I use several ATSs (automatic transfer switchs) to connect my off-grid solar to the house. When the PV -> battery charges up enough to turn on the Inverter - the Inverter power flips the ATSs from grid to inverter. When the batteries run down and the inverter goes off, the ATSs automatically switch back to grid.

At the main panel, I have a 50a@240v ATS + a 10 circuit MTS (manual transfer switch) combination for general circuits / load control. The MTS let's me choose which circuits are 100% grid if I need to lesson the max load on the inverter. A dedicated 12,0000w AIMS inverter feeds this ATS - which is 50a@240v.
View attachment 55702
i love this idea, would like to know more about it.
I love this idea!!! From what I understand, if the power goes out this will automatically kick on? Or is it manual but kick off automatically? Cost $$$,
Do I have to hook it to the whole house or could I skip breakers like the heat and air that suck a lot of power?
 

Jamie.sanders

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Dec 1, 2019
Messages
100
Or is it just automatic (read the post again) it kicks power to your house one enough solar power is saved up, then kicks back to grid when you batteries are depleted?
 

OffGridInTheCity

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Joined
May 23, 2021
Messages
456
Location
Southern Oregon
Or is it just automatic (read the post again) it kicks power to your house one enough solar power is saved up, then kicks back to grid when you batteries are depleted?
Yes. Its an *off-grid* way to consume all PV generated power but yet use the grid as stand-by. If the grid were to go down - to have power 24/7 I would manage my loads carefully so that the system never depleted the battery enough to turn off the inverter.

Some of the all-in-one off-grid units such as MPP Solar PIP and certain GroWatt models include ATS and UPS as part of the all-in-one operations - you just feed in grid power + battery and it manages things. In my case - because of distance issues and the 24,000w scale of things - I did the ATS and UPS as individual components of the overall system.
 
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Cheap 4-life

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Jan 20, 2021
Messages
314
GTIL2 inverters might be an option for you. They only produce what the loads need so they don’t push power past the meter into the grid.
 

MikeR8

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Joined
Jul 17, 2021
Messages
1
I use several ATSs (automatic transfer switchs) to connect my off-grid solar to the house. When the PV -> battery charges up enough to turn on the Inverter - the Inverter power flips the ATSs from grid to inverter. When the batteries run down and the inverter goes off, the ATSs automatically switch back to grid.

At the main panel, I have a 50a@240v ATS + a 10 circuit MTS (manual transfer switch) combination for general circuits / load control. The MTS let's me choose which circuits are 100% grid if I need to lesson the max load on the inverter. A dedicated 12,0000w AIMS inverter feeds this ATS - which is 50a@240v.
View attachment 55702
Do you have model numbers on the transfer switches you used ? This look like the setup I'm seeking
 

OffGridInTheCity

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Joined
May 23, 2021
Messages
456
Location
Southern Oregon
Do you have model numbers on the transfer switches you used ? This look like the setup I'm seeking
I use
- 2 of these (Go Power ATS) - they are 120v @ 30a - https://www.amazon.com/gp/product/B00153EYTO/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

- 2 of these (Progressive Dynamics ATS with Surge) - 240v(120v) @ 50a - https://www.amazon.com/gp/product/B0136U0QU4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
which appear to be temporarily out of stock everywhere.

- 1 of these (Progressive Dynamics ATS without Surge) - 240v(120v) @ 50a Its non-surge + it doesn't have indicator lights - https://www.amazon.com/gp/product/B003VAWNVK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
*Surge can occur when certain motors are ATS'ed over from Grid -> Inverter and vice versa and the sine waves are not synchronized - not been a problem for me personally. Some say refrigerator motors will blow - but no problem for me and its been over 2 years (700+ switches).

- 1 of these (ProTran / Reliance Controls MTS) - https://www.homedepot.com/p/Relianc...ircuit-Manual-Transfer-Switch-A510C/206503336

Notes:
All of these are ETL/UL.

I use 120v LEDs as indicator lights - https://www.amazon.com/gp/product/B07FXCGDDX/ref=ppx_yo_dt_b_search_asin_title - so I can see from 'a far' which side the ATS is on. Green = Inverter side is powered. Yellow = Grid side is powered. By default then, the Inverter side is active.
1627265770476.png
 
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Supervstech

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On the gensets I have installed, the ats has load shedder relays that lock out large demand appliances, and allow only during light consumption times…
 

OffGridInTheCity

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Joined
May 23, 2021
Messages
456
Location
Southern Oregon
On the gensets I have installed, the ats has load shedder relays that lock out large demand appliances, and allow only during light consumption times…
The ATSs I listed above (Go Power and Progressive Dynamics) don't have current limitations / load shedding relays - they're just interconnected mechanical relays with an XXsec delay control board on the generator side input to let a generator stabilize after startup.
 
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