Why do I need a DC-DC Charger? In a nutshell, your DCDC charger will charge your auxiliary battery faster, to a far greater level and safely regardless of your vehicle's alternator type. ... If you have or are considering a lithium battery, then you absolutely have to run a DCDC charger.

Do I need a DCDC charger for AGM battery?

For lead-acid deep cycle batteries such as AGM or Gel, you need a charger with an Amp output of 10-20% of the battery capacity. For example, a 100Ah AGM Battery should have at least a 20Amp DC-DC Charger. ... So with these batteries, we would suggest a DC-DC Charger with an output of 40-50+ Amps.

Do I need a VSR with a DCDC charger?

Any circuit that includes an auxiliary battery that needs to be charged from an alternator source needs a DCDC charger and not a VSR. ... If you have a newer vehicle, run AGM or LiFePO4 batteries or any setup that is outside of the engine bay, then a DCDC charger is required instead of a VSR.