Would I be able to bring a portable iPhone charger I made in my luggage?

I would like to bring a portable iPhone charger, I made, on the airplane, but put it in luggage, not carry-on. Would they take me off the plane? It is just in a metal box with wire, batteries, and a female car charger.

Yes. They should allow it in the luggage. I had two chargers in my luggage (not carry-on) and I didn’t get kicked off the plane. As long as its not in the carry-on bags, you’re good.