A Quick Guide to DC-DC Battery Chargers for Campervans

Introduction

A DC-DC battery charger is a powerful tool that keeps your leisure battery charged while you drive, ensuring readiness for relaxation once parked.

What Is a DC-DC Battery Charger?

A DC-DC (battery-to-battery) charger connects your leisure battery to your vehicle's alternator through the starter battery. While the alternator recharges the starter battery, the DC-DC charger simultaneously charges your leisure battery. This connection is essential because alternators produce variable voltages that could damage sensitive batteries without proper management. Victron DC-DC chargers work with AGM, gel, and lithium battery types.

DC-DC Charger vs. VSR: What's the Difference?

VSR (Voltage Sensing Relay):

  • Simple and inexpensive option
  • Suitable for vehicles with lead-acid batteries and uncomplicated alternator systems
  • Functions like switches, splitting alternator charge between starter and leisure batteries when specific voltage is detected

DC-DC Charger:

  • Smarter and more versatile technology
  • Essential if you have a lithium battery
  • Required for vehicles with smart alternators (common in modern vehicles), which output varying and extreme voltages that only DC-DC chargers can regulate effectively

Isolated vs. Non-Isolated DC-DC Chargers

Non-Isolated:

  • Shares common ground with vehicle chassis
  • Ideal for most standard setups

Isolated:

  • Has no shared ground
  • Used in specialized cases like ex-military vehicles or camper conversions with non-metallic habitation boxes
  • Recommended as a universal choice if uncertain, as these work in all applications

Starter Battery Voltage: Know Before You Buy

Check your vehicle's starter battery voltage (typically 12V or 24V) and leisure battery voltage. Ensure your selected DC-DC charger matches both battery types and system voltage. For example, a 12/24 charger accommodates a 12V starter battery paired with a 24V leisure battery system.

LUX Solar provides a "DC-DC Charging Tool" that helps select the correct charger and generates appropriate wiring kits for quick setup.

Choosing the Right Size Charger

Your DC-DC charger's capacity determines leisure battery recharge speed. Consider:

  1. Desired recharge speed
  2. Battery charging limits

Victron Orion Smart DC-DC chargers are highlighted as popular choices. These chargers offer easy Bluetooth installation and configuration, providing efficient charging in compact, durable packages.

Note: Victron chargers do not include battery connection cables. LUX Solar's DC-DC Charging Tool creates custom prewired cable kits for installations.

Ready to Upgrade?

DC-DC battery charger kits from LUX Solar include everything needed -- charger, cables, fuses, and detailed wiring diagrams -- for seamless installation.