Quick picks
- Best overall: 100Ah LiFePO4 with built-in heater — usable capacity, lifespan, and weight all win.
- Best value: Group 31 AGM — half the upfront cost when your draw is light.
- Best for cold climates: Self-heating lithium that charges below freezing.
At a glance
| Battery type | Usable capacity* | Cycle life | Weight (100Ah) | Best for |
|---|---|---|---|---|
| LiFePO4 (lithium) | ~100% (100Ah) | 3,000–5,000 | ~26 lb | Full-timers, boondockers |
| AGM | ~50% (50Ah) | 500–1,000 | ~63 lb | Weekenders, budget builds |
| Flooded lead-acid | ~50% (50Ah) | 300–600 | ~58 lb | Tight budgets, ventilated bays |
*Usable capacity = how much you can safely draw before damaging the battery. This is the number that actually matters off-grid.
The reviews
100Ah LiFePO4 with Low-Temp Protection
A self-heating 100Ah lithium gives you a true 100Ah to work with, charges fast, and shrugs off deep discharges. Over a few seasons it's usually cheaper per usable amp-hour than AGM despite the higher sticker.
Pros
- Full usable capacity
- ~10-year lifespan
- Less than half the weight
- Charges below freezing (heated models)
Cons
- Higher upfront cost
- May need a compatible converter/charger
Group 31 AGM Deep-Cycle
If you mostly camp with hookups and only need backup for short stints, a quality AGM is sealed, maintenance-free, and easy on the wallet. Just remember you only get about half its rating in usable power.
Pros
- Low upfront cost
- Sealed, maintenance-free
- Widely available
Cons
- ~50% usable capacity
- Heavy
- Shorter lifespan
Self-Heating 100Ah LiFePO4
Lithium hates charging below freezing. A built-in heating pad solves that, drawing a little power to warm the cells before accepting a charge — essential for winter camping and four-season rigs.
Pros
- Charges in sub-freezing temps
- All the lithium upsides
Cons
- Premium price
- Heater sips a little power
How to choose
1. Size your bank to your real draw
Add up your daily amp-hours (fridge, lights, water pump, devices). Off-grid, plan for lithium at ~100% usable and lead-acid/AGM at ~50%. Two 100Ah AGMs roughly equal one 100Ah lithium in real usable power.
2. Match your charging
Lithium wants a lithium-aware converter and ideally DC-DC charging from the alternator. Budget for the charger, not just the battery.
3. Weight and space
Lithium saves 60–70% of the weight for the same usable capacity — a big deal for payload and tongue weight.