The REDARC BCDC1240D under bonnet Battery Charger is a 12/24V 40A DC to DC battery charger, capable of high performance in engine bay installations, potted to survive and thrive against heat, water and dust.Featuring a Maximum Power Point Tracking (MPPT) solar regulator, the BCDC1240D Classic will charge from both solar and the alternator simultaneously. With built-in ‘Green Power Priority™’ it will select solar charging first, meaning less load on the alternator.Suitable for 12 or 24-volt vehicle systems, the unit will also work with either standard or variable/smart alternators.