How Long Will a 200Ah Battery Last?
A 200Ah battery is one of the most popular sizes for RV, marine, solar, and home backup applications. Understanding its real-world runtime under different loads helps you plan power systems that actually meet your needs.
Total Energy vs. Capacity
"200Ah" describes charge capacity, but runtime depends on total energy, which also requires knowing the voltage. A 200Ah battery at different voltages stores vastly different amounts of energy:
| Voltage | Total Energy | Usable (80% DoD) |
|---|---|---|
| 12.8V (4S LFP) | 2,560 Wh | 2,048 Wh |
| 25.6V (8S LFP) | 5,120 Wh | 4,096 Wh |
| 51.2V (16S LFP) | 10,240 Wh | 8,192 Wh |
This is why comparing batteries by Ah alone is misleading. A 200Ah 48V battery stores four times the energy of a 200Ah 12V battery, even though the Ah rating is identical.
Runtime Formula
For all examples below, we assume LFP chemistry at 80% DoD and 90% system efficiency unless stated otherwise.
Worked Example: Common Loads
Given: 200 Ah at 12.8V LFP battery, 80% DoD, 90% efficiency
Usable energy:
Effective load with efficiency correction:
Runtime Table: 200Ah 12.8V LFP
This table shows runtime for typical loads you might encounter in RV, marine, or home backup scenarios.
| Load | Power (W) | Runtime |
|---|---|---|
| Phone charging (×3) | 15 W | ~121 hours |
| LED lights (×4) | 24 W | ~76 hours |
| Laptop | 60 W | ~30 hours |
| 12V camping fridge | 50 W | ~36 hours |
| TV + streaming stick | 100 W | ~18 hours |
| Coffee maker | 800 W | ~2.3 hours |
| Microwave | 1,000 W | ~1.8 hours |
| Space heater | 1,500 W | ~1.2 hours |
Scenario: Weekend RV Camping
A typical weekend camping trip (2 nights, 3 days) with the following loads:
| Appliance | Daily Use | Energy (Wh) |
|---|---|---|
| 12V fridge (24h) | Continuous | 600 Wh |
| LED lights (5h) | 5 hours | 30 Wh |
| Phone + tablet | 2 hours | 30 Wh |
| Water pump (10 min) | 3× daily | 50 Wh |
| Daily Total | 710 Wh |
With 2,048 Wh of usable energy from a 200Ah 12.8V LFP battery, this camping setup runs for approximately 2.9 days — covering a full weekend trip without recharging. If you have solar panels, even a small 100W panel in good sun can replenish 400–500 Wh per day, extending the trip indefinitely.
Scenario: Home Backup
For home backup during a power outage, prioritizing critical loads only:
Essential Loads Only
Router (10W) + fridge (50W) + 4 LED lights (24W) + phone charging (15W) = ~99W
Runtime: ~18.6 hours — enough for overnight coverage.
Essentials + Medical Device
Add CPAP machine (30W) to essential loads = ~129W
Runtime: ~14.2 hours — still covers a full night plus morning.
Chemistry Comparison
The runtime of a 200Ah battery varies significantly with chemistry. Lead-acid batteries have lower usable DoD and suffer the Peukert effect at higher loads:
| Chemistry | Usable DoD | Usable Energy | Runtime at 100W |
|---|---|---|---|
| LFP (LiFePO4) | 80% | 2,048 Wh | ~18.4 hrs |
| NMC (Lithium) | 80% | 2,048 Wh | ~18.4 hrs |
| AGM Lead-Acid | 50% | 1,280 Wh | ~11.5 hrs |
| Flooded Lead-Acid | 50% | 1,280 Wh | ~10.2 hrs* |
* Flooded lead-acid runtime is lower due to the Peukert effect reducing usable capacity at moderate discharge rates.
Try It
Use the Runtime Calculator to estimate discharge duration for your specific loads and battery configuration.
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Read Guide →Frequently Asked Questions
How long will a 200Ah battery run a fridge?
A typical 12V fridge draws 40–60W continuously (compressor cycling). A 200Ah 12.8V LFP battery at 80% DoD provides 2,048 Wh of usable energy. Divided by 50W at 90% efficiency, runtime is approximately 36 hours. Actual time varies with ambient temperature and how often the door is opened.
How long will a 200Ah battery run a 1000W inverter?
At 1000W AC load with 90% inverter efficiency, the battery sees 1,111W. A 200Ah 12.8V LFP battery at 80% DoD provides 2,048 Wh. Runtime is approximately 1.84 hours, or about 1 hour 50 minutes.
Is a 200Ah battery enough for camping?
For a weekend camping trip (2–3 days) with moderate loads (fridge, lights, phone charging), a 200Ah 12V LFP battery is usually sufficient. For extended off-grid stays or heavy loads (air conditioning, heating), you may need 400Ah or more.
Does voltage matter when comparing 200Ah batteries?
Yes. A 200Ah battery at 12.8V stores 2,560 Wh. The same 200Ah at 25.6V stores 5,120 Wh — double the energy. Always compare total energy (Wh), not just Ah, when evaluating batteries.