A reliable dual-battery and charging system is the backbone of any overlanding rig. Whether you need a DC-DC charger to keep your auxiliary battery topped up from the alternator, a solar blanket for camp charging, or a complete power management system — we compare the best options for US overlanders.
8 products reviewed
Best for: Any overlanding rig with a lithium or AGM auxiliary battery
Best for: Budget builds with flooded/AGM batteries and older vehicles
Best for: Clean installs where you want one box to do everything
Redarc
Max Current
50A
Solar Input
750W
MPPT
Built-in
IP Rating
IP67
Weight
0.85 kg
Warranty
2 yr
Batteries
LFP, AGM, gel, lead-acid, calcium
Renogy
Max Current
50A
Solar Input
660W
MPPT
Built-in
IP Rating
IP32
Weight
1.42 kg
Warranty
2 yr
Batteries
LFP, AGM, gel, lead-acid
Victron Energy
Max Current
30A
IP Rating
IP43
Weight
1.4 kg
Warranty
5 yr
Batteries
LFP, AGM, gel, lead-acid
CTEK
Max Current
20A
Solar Input
300W
MPPT
Built-in
IP Rating
IP65
Weight
1 kg
Warranty
2 yr
Batteries
LFP, AGM, gel, lead-acid, calcium, EFB
Redarc
Max Current
30A
Solar Input
520W
MPPT
Built-in
IP Rating
IP65
Weight
1.6 kg
Warranty
2 yr
Batteries
LFP, AGM, gel, lead-acid
Renogy
Max Current
11A
Solar Input
200W
IP Rating
IP54
Weight
4.4 kg
Warranty
5 yr
Batteries
LFP, AGM, gel, lead-acid
National Luna
Max Current
100A
IP Rating
IP67
Weight
2.3 kg
Warranty
2 yr
Batteries
LFP, AGM, gel, lead-acid
WirthCo Battery Doctor
Max Current
125A
IP Rating
IP62
Weight
0.5 kg
Warranty
1 yr
Batteries
AGM, gel, lead-acid
A DC-DC charger is the modern standard. It provides multi-stage charging (bulk, absorption, float) that protects your battery and maximizes lifespan — essential for lithium (LFP) batteries. An isolator is a simple relay that connects batteries directly, which works for flooded/AGM but can damage LFP cells and doesn't work with smart alternators found in most vehicles from 2015+.
If you use portable solar panels, yes. MPPT (Maximum Power Point Tracking) extracts 20–30% more energy from your panels than a basic PWM controller. Many DC-DC chargers (Redarc BCDC1250D, Renogy DCC50S, CTEK D250SA) have MPPT built in, so you can connect solar directly without a separate controller.
LFP is superior in every way except upfront cost: 50% lighter, 3,000+ cycles vs 400 for AGM, usable to 80–100% depth of discharge vs 50% for AGM, and faster charging. A 100Ah LFP battery gives you 80–100Ah of usable capacity vs only 50Ah from a 100Ah AGM. Over its lifetime, LFP costs less per cycle.
Add up your daily power consumption in Ah or Wh: fridge (~40Ah/day), lights (~5Ah), phone charging (~5Ah), laptop (~15Ah). A typical overlanding setup uses 60–80Ah/day. Your battery should be 1.5–2x your daily use (120–160Ah for LFP, 200+ Ah for AGM at 50% DoD). Your DC-DC charger should be sized to replenish the battery in 2–4 hours of driving.