House Battery
The 12V battery (or bank) that powers an RV's interior systems — lights, water pump, fan, propane controls. Distinct from the chassis starter battery.
Also called: house battery, house battery bank, coach battery, 12V battery, deep cycle battery
The house battery (or house battery bank) is the 12V battery system that powers an RV’s interior 12V loads — lights, water pump, propane refrigerator controls, vent fans, and the slide-out motor. It’s distinct from the chassis battery, which starts the engine.
How the house battery charges
Three charging sources:
- Shore power. When plugged into a campground pedestal, the RV’s converter charges the house battery.
- Generator runtime. When the onboard generator runs, the converter also charges.
- Solar (if equipped). Roof-mounted solar panels charge through a charge controller.
- Engine alternator (motorhomes only). When driving, the engine charges both the chassis and house batteries.
Towables (travel trailers, fifth wheels) only charge from shore power, generator, or solar. They don’t charge from the tow vehicle’s alternator except marginally through the trailer’s 7-pin connection.
Battery technology tiers
| Battery type | Capacity | Cycle life | Cost | When used |
|---|---|---|---|---|
| Flooded lead-acid | 80-100 Ah | 200-400 cycles | $80-150 | Cheapest; in many older rentals |
| AGM (sealed lead-acid) | 100-200 Ah | 400-800 cycles | $150-300 | Mid-tier; most modern rentals |
| Lithium (LiFePO4) | 100-300 Ah | 3,000-5,000 cycles | $600-1,500 | Premium; high-end Class B builds, boondocking rigs |
What this means for renters
For typical full-hookup camping, house battery capacity matters little — you’re plugged in and the battery is always topped up.
For boondocking and dispersed camping, house battery capacity drives how long you can stay off-grid:
- Single 100 Ah flooded battery (no solar): 1 night
- Dual AGM batteries: 2 nights
- 100 Ah lithium + 200W solar: 4-5 nights
- 300 Ah lithium + 400W solar: 7+ nights
If you’re renting for an off-grid trip, ask about battery type and solar wattage before booking. The difference between a 2020 lithium setup and a 2014 single-battery rig is the difference between a successful boondocking trip and a frustrated one.