FETFan

Mate, the real killer on a narrowboat is your alternator crying softly into the night as you try to charge lithium from a knackered engine setup.

Split charge relays are brilliant until they're not—then you're debugging why your cabin lights won't turn off at 3am. Since you're PWM solar-only, honestly?

Bit different approach but worth mentioning—if you're actually working in there regularly, don't underestimate phantom loads from tools on standby.