I’m planning the electrical side of my first van build and trying to decide whether to add a dedicated backup power setup next to the main house bank. My plan is a simple 12V system with a couple of 100Ah lithium batteries, a DC-DC charger, and solar on the roof. A few people I’ve talked to keep a separate smaller backup battery they can use if the main system goes down, and I’ve been reading about home-style backup power units people adapt for van use. My concern is weight and space in a short-wheelbase van, plus whether a second independent system is actually worth the extra wiring and cost, or if it’s better to just size the main bank bigger and carry a jump pack. I haven’t bought anything yet and don’t want to overbuild. Curious what those of you with real van builds have done and whether you’d go the separate backup route again.