Renogy 12V 40A DC to DC On-Board Battery Charger Temperature Control?:No Solar panels also allow you

Solar panels also allow you to run limited low watt electrical equipment without a power hookup

It is equipped with half-cut PERC cell technology that enhances solar light capture and electrical performance

For a standard 400/450mm roof light you'll need 6 of these in total so that's why we sell them in packs of 6

This product has as built in Voltage Sensing Relay so will start charging your 2nd battery once the voltage from your alternator reaches 13

the Voyager is engineered to be of world-class quality

Renogy 12V 40A DC to DC On-Board Battery Charger Temperature Control?:No Solar panels also allow youCompatible Multiple Battery Types: Compatible with a multitude of alternator types, the DC DC battery charger offers correct charging for AGM, Flooded, Gel, and Lithium batteries. Smart 3 stage Charging: The DC DC battery charger will charge your house batteries from the starter battery by 3 stage charging (Bulk, Boost, and Float), to make sure it optimally and automatically charge to 100%. Various Protections For Ultra Safety: Offers Over voltage