Why do you require a DC to DC Charger?
Your Smart Alternator can have a significant effect on the amount of charge your house battery receives while you are driving. As the alternator charges only under a “regenerative braking” process (i.e. closed throttle braking) that actual amount of charge is insufficient to maintain your house battery. As your fridge can draw up to and including 20A whilst driving, it is not uncommon to have house batteries in a lower state of charge than when your journey started. The DC to DC 40 amp charger is triggered from the vehicles alternator and steps up the charge to ensure your house batteries receive the correct charge amount to bring them to a fully charge state whilst you travel. The DC to DC charger switches off when the ignition key is off, so there is no house battery to starter battery discharge.