Battery Isolators & Combiners

One alternator or charger, two batteries — this category covers both ways to manage them. Isolators (Argo diode and FET) split the charging current permanently and prevent one battery from discharging into the other — no moving parts, no settings. Battery combiners (Cyrix relays) connect the batteries automatically while charging voltage is present and separate them when charging stops. Choose an isolator for a fixed, maintenance-free split; choose a combiner when you want both batteries charged from one source with virtually no voltage drop.