167 amps vs 42 amps, same power

This is the decision people make by default and regret with a copper bill.

Why current is what costs you. 167 amps needs seriously fat, expensive cable. 42 needs a fraction of it. Copper is priced by weight. Across a build the difference is often hundreds of dollars — before you count the voltage drop, the heat, and the high-current fuses.

The rules that hold up: - 12V — small builds, mostly DC loads, under ~1,500W continuous. Everything in the RV world is natively 12V, so it's simple. - 24V — the middle ground. Halves your current, components widely available. - 48V — cabins, homesteads, air conditioning, induction. It's where residential solar lives, so parts are mature and cheap per watt.

The line I'd draw: if continuous current at 12V heads past about 150A, step up.