How Long Will a 200Ah or 300Ah Battery Last?
By Frank Zale · August 7, 2026 · 2 min read
A 200Ah LiFePO4 battery holds about 2,048 usable watt-hours and a 300Ah bank about 3,072 Wh — enough to run a full remote-work van for one to three days with no charging. That roughly doubles and triples what a 100Ah battery delivers. Here are the real runtimes.
Usable energy first
You never use a battery's full rating. LiFePO4 gives about 80%:
| Bank | Rated | Usable (80%) |
|---|---|---|
| 200Ah LiFePO4 | 2,560 Wh | ~2,048 Wh |
| 300Ah LiFePO4 | 3,840 Wh | ~3,072 Wh |
| 200Ah AGM | 2,440 Wh | ~1,220 Wh (50%) |
Note how a 200Ah AGM gives barely more usable energy than a 100Ah lithium — the chemistry gap is huge.
Runtimes on a 200Ah bank (2,048 Wh usable)
| Appliance | Draw | Runtime |
|---|---|---|
| 12V fridge | 45W cycling | ~4 days |
| Diesel heater | 30W avg | ~68 hours |
| Starlink | 50W | ~40 hours |
| Laptop (via inverter) | 65W | ~28 hours |
| Induction cooktop | 1,500W | ~75 min |
A real full-timer day
| Load | Wh/day |
|---|---|
| Fridge | ~500 |
| Lights + fan | ~200 |
| Laptop + Starlink | ~700 |
| Occasional cooking | ~300 |
| Total | ~1,700 Wh |
- 200Ah (2,048 Wh): ~1.2 days without charging
- 300Ah (3,072 Wh): ~1.8 days without charging
Add solar or driving and either bank runs indefinitely. The battery's job is to bridge the gaps — cloudy days and nights — not to power everything alone.
Which size do you need?
- 200Ah: the full-time sweet spot for most remote workers with solar.
- 300Ah: heavy users, electric cooking, or winter travel where charging pauses in the cold and winter solar is halved.
Compare the jump from 100Ah in the 100Ah vs 200Ah guide, then confirm your exact number with the free calculator.
FAQ
How long will a 200Ah battery last?
About 2,048 Wh usable — roughly 4 days for a fridge alone, or 1–1.5 days running a full remote-work setup (fridge, lights, laptop, Starlink) with no charging.
Is 200Ah or 300Ah better for van life?
200Ah suits most full-timers with solar. Choose 300Ah for electric cooking, very high daily use, or winter travel where charging is intermittent.
How many solar watts to recharge a 200Ah battery?
Roughly 400W of solar replaces a typical day's use in good sun. Size battery and solar together with the calculator.