I have an inverter, a battery bank, a PWM solar controller, and some solar panels. The inverter also supports charging the batteries from the mains power. So if I just plug the inverter into a wall socket, it will charge the batteries. My requirement is that I want the batteries to charge BOTH from the inverter and solar panels (not necessarily at the same time).
My first idea was to just connect both the inverter and solar controller to the battery, like this:
The problem I see with this setup is that this might confuse the inverter when it sees the battery voltage going up and down as the solar controller tries to charge it. Or, would it damage the inverter as it expects a voltage below 26V from the battery, and yet the solar controller charges it at, say, 29V? Is this a valid concern?
Another approach I can think of would be to use a DPCO changeover switch to change whether the inverter is connected to the battery terminals or to the backend of the solar controller:
I could set it to the P1 position when I want to charge the batteries from solar, AND/OR when I want to draw current from the inverter.
I could set it to the P2 position when I want to charge the batteries from the inverter.
Is this an overkill, or should I stick to the first approach? Or is there a better way to implement this?
Ps- I live in a country where access to high power diodes is very limited :)