Yes, you can physically install a standard car battery in an RV, but it is generally a poor choice for powering your RV's living area (the "house" system) and can lead to premature failure. The critical difference lies in the battery's design purpose. A car battery is a starting battery, engineered to deliver a very large burst of power (measured in Cold Cranking Amps, or CCA) for a few seconds to start an engine. It's not designed to be repeatedly drained and recharged. An RV's house system requires a deep-cycle battery, which is built to provide a lower, steady amount of power over a long period and can withstand being discharged down to 50% of its capacity hundreds of times.
Using a car battery for your RV's appliances (lights, water pump, fridge) will significantly shorten its lifespan. The internal lead plates are thinner and can be damaged by the deep discharge cycles, a process called sulfation. For reliable, long-term power, a dedicated deep-cycle battery, such as an Absorbent Glass Mat (AGM) or Lithium Iron Phosphate (LiFePO4) battery, is the correct investment.
| Battery Type | Primary Function | Ideal for Discharge Down To | Key Metric | Lifespan (Cycles) |
|---|
| Car (Starting) Battery | Engine Cranking | 80-90% State of Charge | High Cold Cranking Amps (CCA) | 200-500 (if used as deep-cycle) |
| Marine Deep-Cycle | Mixed Use (Starting & Trolling) | 50% State of Charge | Reserve Capacity (RC) | 500-800 |
| True Deep-Cycle (Flooded) | RV House Power, Golf Carts | 50% State of Charge | Amp-Hours (Ah) | 800-1500 |
| AGM Deep-Cycle | RV House Power | 50% State of Charge | Amp-Hours (Ah) | 800-1200 |
| Lithium (LiFePO4) | RV House Power | 20% (or lower) State of Charge | Amp-Hours (Ah) | 3000-5000+ |
The only scenario where a car battery is appropriate in an RV is for the vehicle's engine chassis battery, which is solely for starting the motor. Never use it to replace your house batteries.
