Newbie: Several Questions about on-grid and off-grid

[logslogs]

Hi,

I am new to all this excuse my ignorance. I am trying to have a setup with the following requirement:

- We have frequent power failures schedules here of combined 4-6 hours / day (1 hour fixed each time). So on-grid is not good enough.
I need the backup from batteries and I want the solar to continue producing power at day-time. Hybrid is the solution but it's too expensive in my country.

- I will be exporting to the electric provider as they exchange the units used from grid vs exported.

1. I want to do a 12kw solar setup but can only afford 6kw Hybrid solar inverters. I can afford a 12kw on-grid solar inverter + a smaller 5-7kw off-grid solar inverter (for when grid power is out) - they are still way cheaper than buying the hybrid. Heck, even 12kw of off-grid+on-grid would be cheaper than hybrid.

Is there any way to make that work?

2. About 5-7kw of the house load on this setup. But I want to keep rest of load separate so it doesn't ever overload the inverter. That's possible right?

Thank you for the suggestions and replies.

 

[The Super Minion]

Yes it is possible but it would be difficult to get auto switching since the offgrid inverter cannot 'sense' if the electricity is out or not. First you need a critical load panels that seperate your critical loads. Then you can install a generator transfer switch to your critical load panel. And then connect your offgrid battery/inverter to the transfer switch. When the power cuts happen, manually change the transfer switch so the critical load panel gets power. There are automatic transfer switches but they are expensive.

 

[Rednecktek]

The hybrids that can do all your back feeding and run from battery usually end up cheaper than getting 2 systems set up and the transfer switches and all. The reason for the cost difference usually comes down to all the regulation requirements for the back feeding.

Getting a critical loads panel installed tends to be a bit pricy BUT it significantly reduces the size and cost of the inverter.