Mastervolt Charge Mate Pro Lithium 40 [83304004]Charge Mate Pro Lithium 40 Current limited electronic charge relay with high efficiency and reverse current protection A secondary battery on board requires a dedicated charging solution. The Charge Mate Pro charging relay makes it possible to distribute the charger or alternator current effectively between two battery banks such as a starter and a service battery. The Charge Mate Pro connects both batteries during charging and keeps them isolated