For general physics I'd recommend Feynman's Lectures, which with your background may be too basic, I don't know.
Engineering wise I'd recommend Horowitz' Art of Electronics.
Aside from that there's so many resources available these days that's it's hard for me recommend one thing but I'd say start collecting sources online and cross referencing.
I know there's a lot of optimization and programming within designing microgrids and battery systems.
So with your background I'd say you're already 70-90% there and the background on theory that the above mentioned books ought to help you with would get you pretty far aside from very particular things.
Hope that helps!
