How Long Will a 100Ah Battery Last?
The 100Ah battery is the most popular capacity for RV, van life, and marine applications. It provides 1,200Wh total (960Wh usable) at 12V - enough to run a CPAP all night, keep a 12V fridge running, and charge devices for several days.
Capacity
100Ah
Total Energy (12V)
1200Wh
Usable (80% DoD)
960Wh
Typical Use
RV/Van life
Runtime Calculator
Runtime at 100W
8.2 hours
0.3 days if running continuously
Total Capacity
1200Wh
Usable (80% DoD)
960Wh
Solar Charging
* Actual runtime varies based on temperature, battery age, and load consistency.
Runtime Examples at 100Ah
| Device | Power Draw | Runtime |
|---|---|---|
| CPAP (no humidifier) | 30W | 27 hours |
| 12V fridge (running) | 50W | 16 hours |
| Laptop + lights | 100W | 8 hours |
| TV + fan | 200W | 4 hours |
| Microwave (low) | 500W | 1.6 hours |
* Based on 12V LiFePO4 with 80% depth of discharge and 85% inverter efficiency.
- ✓Weekend van trips
- ✓RV backup power
- ✓Marine house battery
- ✓CPAP backup
- ✓Small cabin
- ✗Full-time off-grid
- ✗Running AC
- ✗Multiple high-draw appliances
- ✗Extended cloudy periods
100Ah Battery Tips
- •The sweet spot for van life and weekend RV trips
- •Can run a CPAP for 3+ nights without humidifier
- •Pairs well with 200W of solar panels
- •LiFePO4 weighs about 25-30 lbs, lead acid about 65 lbs
- •Two 100Ah batteries in parallel doubles capacity without voltage change
Frequently Asked Questions
How long will a 100Ah battery run a refrigerator?
A typical 12V RV fridge (50W average) will run about 16 hours on a 100Ah LiFePO4 battery. Compressor fridges cycle on/off, so actual runtime may be 24+ hours.
How long to charge a 100Ah battery with solar?
With 200W of solar panels in full sun, about 6-7 hours from 20% to full. A 100W panel takes about 12 hours. Factor in clouds and panel angle for real-world estimates.
Is 100Ah enough for an RV?
For weekend trips with moderate use, yes. For full-time living or running AC, you likely need 200-400Ah. It depends heavily on your power consumption habits.