Adding/removing loads to match solar production levels

[joelspangler]

Sorry if the answers to these are obvious, but I'm a newb. Looking to add a 10-12kw solar array with batteries to take part of my home off-grid, and avoid some of the hoops to jump through to export to the grid. I don't think this system will be large enough to handle my 30 ton heat pump, and things like my electric water heater, and stove. Here in PA, production will vary greatly from Summer to Winter, and I would probably want to run more of my home off of solar during the summer months (and less during the winter).

1 - How would one accomplish adding/removing loads to match production at a certain time of year? Would I need to manually move breakers from my "off grid" panel, to the grid tied one, or is there a way to automate or at least make it easier than moving breakers?

2 - I'd probably want to run even less stuff during grid outages - again is there a way to automate this, or would I need to go turn off certain breakers during grid outages?

3 - I've been trying to decide if I'd want my batteries inside or in my garage. I'm thinking of something like a short rack of lithium server rack batteries. I know they don't operate in cold well, and I'd need units with built in heaters. How much of a power load does it take to keep batteries warm enough to operate when it's below freezing? I know lithium batteries sometimes do catch on fire - how much of a concern is this? Should I be concerned about putting batteries inside my home?

 

[ScrotusGobbleBottom]

Probably a sub panel with new wiring and outlets for all the things that you want powered. You would then connect that sub panel to and inverter/charger that would be hardwired to the main panel. This way you can just activate bypass mode on the inverter/charger when you dont have enough stored power. And in the event of inverter failure, there is still the original outlet right there near the device.

That is what I have done. It has been working great.

 

[DIYrich]

I don't think this system will be large enough to handle my 30 ton heat pump, and things like my electric water heater, and stove.

That's a commercial size unit. You would need more than 10kw of solar to run that.

You want a load controller like Span.io or Savant. You can turn loads on and off automatically based upon priority.

 

[joelspangler]

Sorry - I'm an idiot - it's a 3-ton heat pump (not 30). I'm a bit confused by the ScrotusGobbleBottom's remark - it sounds like he may have run separate outlets around his house - one for grid and one for off-grid. Is that typical - seems like that would be a lot of work and almost a remodel? Is that the common way to do partial off-grid?

 

[ScrotusGobbleBottom]

it sounds like he may have run separate outlets around his house - one for grid and one for off-grid. Is that typical - seems like that would be a lot of work and almost a remodel?

correct. But only a couple. 2 circuits in basement 2 upstairs and 3 downstairs. Got all the bases covered tho. Furnace, and freezer in basement, fridge and microwave in kitchen, gas fireplace, and my bedroom for ac and computer. That way if the power goes out, I dont care. I just notice the light switches dont work anymore

 

[Texican]

I have both grid tie and an off grid system. In some conditions I like to be able to control if a load is on the grid or on the off grid system.
I installed a switch which allows me to control this.
this switch controls one of our mini splits (normally on the off grid side)
I may install another switch for the electric water heater ( normally on the grid side)