Dual Battery Charger

A dual battery system has two batteries with two jobs. The starter battery starts the engine and must always hold enough charge to do so. The second battery, often called the house or auxiliary battery, runs lights, fridges, communications, and other loads while the engine is off. The charger that links them must charge the second battery from the starter system while driving, and must not let the second battery's loads drain the starter battery when parked.

The charger category on this site supports that setup in two ways. The bidirectional series can move energy in both directions and supports charging while the engine runs, which suits a dual battery installation where the auxiliary bank must both charge and supply. The category-level charger lines include a bidirectional battery charger line and a lead-acid battery charger line, for configurations the detail page does not cover.

Two questions decide a dual battery specification: the voltages of the two banks, and whether the auxiliary bank is lithium or AGM, since the charging profile differs. State both banks, both chemistries, and the auxiliary load in the inquiry, and before ordering, confirm quantity, price and delivery time. Certificates are available upon request.