Connect all in one inverter to which load center, and why?

[WorldwideDave]

I want to add solar to my home. I don't want to backfeed to the utility. Battery would be added. Truly not relying on the grid is the option, though I'll have to keep it connected to the house and pay the 30/month or whatever it is. Would be nice to use grid to charge battery on bad sun day/dead batteries/maintenance mode.

I have an old load center at the back of a house near a pool where the grid connection is located. 100 years old house, 100 amp panel is plastered into side, probably done in the 1960s (Cutler Hammer brand), and very few (5?) circuits still go there. No lockouts, no 'main' breaker at the top, and not a 'solar ready' panel.

Inside the panel, there is a 100A 240V DPDT breaker to disconnect the meter in the middle of the panel they call the 'main disconnect'.

At the bottom of this same panel is another 100A 240V DPDT breaker that is a disconnect for a subpanel about 70 feet away in the garage area, added in 1970 we believe. The panel in the garage downstairs has some good newer wires run to it. No aluminum wires left in the house. This is the panel I put the Emporia Vue 3 into, and it's a packed panel wow.

Anyway, trying to decide between two system designs.

In one design, I put the all-in-one next to the main original load center upstairs. I really don't want to touch any of those nylon string wrapped wires likely still in there if I can avoid it. Didn't want to swap the panel back there, as that may be a huge can of worms. That 'section' of the house has a lot of older wires in it. Don't love it.

In the other design, I put the all-in-one into the garage downstairs near the newer panel. However, that panel is overloaded in my opinion right now, as it is a smaller murray panel with 16 breakers in it, and probably 4 of the tandem/double breakers. It's a mess, and I don't love it.

Once design is picked, I'll figure out the replacement of a panel, if needed, and start with that.

I appreciate you reading. Open to suggestions on design.

Attached drawings are not to scale or professional in any way. Inverter/SCC/MPPT would be one icon.

Note: Trying to do this WITHOUT permit. Figuring out where to mount the panels I have is what I'm focused on this week.

 

[DIYrich]

Put the AIO between the grid disconnect and first panel. That will backup your whole house. No need to touch and wires, except the one going into the first panel.

If you put between first and second panel, the either: 1) need CTs on wire between disconnect and first panel, and risk backfeeding grid; or 2) only provide power to 2nd panel.

Any option will require a permit. If you use an AIO that cannot interact with the grid (other than passthrough or only charge battery) then you can avoid power company permission.

 

[WorldwideDave]

Any option will require a permit. If you use an AIO that cannot interact with the grid (other than passthrough or only charge battery) then you can avoid power company permission.

That's the plan

 

[WorldwideDave]

Put the AIO between the grid disconnect and first panel. That will backup your whole house. No need to touch and wires, except the one going into the first panel.

Thank you. Just stupid-old panel. I'll take a look this weekend.

 

[WorldwideDave]

If you put between first and second panel, the either: 1) need CTs on wire between disconnect and first panel, and risk backfeeding grid; or 2) only provide power to 2nd panel.

Thanks Rich - wasn't my goal to put 'between' - look at the photos. flow would be more like AIO-->downstairs panel-->wires exist up to old main panel already-->disconnect the main from the grid via a switch. That way sun to AIO to downstairs panel to main panel and off to all the branches from main panel and downstairs panel.