2,560Wh
LiFePO4 Usable
51 hrs
at 50W Load
2x
vs AGM Usable
A 200Ah battery runtime depends on your battery chemistry and load. A 200Ah LiFePO4 at 12V gives you 2,560Wh of usable energy - enough to run a fridge for 17 hours, a CPAP for 10+ nights, or power an RV overnight with lights, fridge, and phone charging. A 200Ah AGM gives you only half that (1,200Wh usable) due to the 50% depth of discharge limit.
The question "how long will a 200Ah battery last?" doesn't have a single answer because it depends on what you're running. A 200Ah battery powering a single LED light lasts over a month. That same battery running a microwave lasts 2 hours.
This guide gives you the specific runtime for every common appliance, shows you realistic multi-device scenarios, and explains why a 200Ah LiFePO4 delivers twice the runtime of a 200Ah AGM.
200Ah: How Much Energy Is That?
Amp-hours (Ah) tell you the battery's capacity, but watt-hours (Wh) tell you how much energy you can actually use. The conversion depends on voltage and how deeply you can discharge.
Usable Wh = Ah × Voltage × Depth of Discharge
| Battery Type | Rated Ah | Safe DoD | Usable Wh |
|---|---|---|---|
| 200Ah LiFePO4 (12V) | 200Ah | 100% | 2,560Wh |
| 200Ah AGM (12V) | 200Ah | 50% | 1,200Wh |
| 200Ah Flooded Lead-Acid | 200Ah | 50% | 1,200Wh |
Use our Ah to Wh Calculator to convert any battery's amp-hour rating to usable watt-hours.
Single Device Runtime: 200Ah LiFePO4
The table below shows runtime for a 200Ah LiFePO4 battery (2,560Wh usable) powering individual devices. Devices running through an inverter (AC loads) include a 15% efficiency loss.
| Device | Watts | Power Type | Runtime |
|---|---|---|---|
| LED Lights (4 bulbs) | 40W | 12V DC | 64 hours |
| Phone Charging (x2) | 20W | 12V DC | 128 hours |
| Laptop | 60W | AC | 36 hours |
| CPAP (no humidifier) | 30W | DC | 85 hours (10+ nights) |
| CPAP (with humidifier) | 60W | AC | 36 hours (4-5 nights) |
| 12V Camping Fridge | 45W avg | 12V DC | 57 hours (2+ days) |
| Residential Fridge | 150W avg | AC | 14.5 hours |
| Chest Freezer | 40W avg | AC | 54 hours (2+ days) |
| TV (42") | 80W | AC | 27 hours |
| Box Fan | 75W | AC | 29 hours |
| Coffee Maker | 1,000W | AC | 2.2 hours |
| Microwave | 1,200W | AC | 1.8 hours |
AC runtime includes 85% inverter efficiency. Fridge and freezer watts are averages accounting for compressor cycling (on ~30% of the time). Actual runtime varies by model, ambient temperature, and usage patterns.
For detailed fridge runtime analysis, see our 100Ah Battery for Fridge guide (double those numbers for a 200Ah battery). For CPAP-specific sizing, see CPAP Solar Power.
Real-World Multi-Device Scenarios
Nobody runs just one device. Here's how a 200Ah LiFePO4 battery handles realistic multi-device loads.
RV Overnight (12 hours)
ComfortableA 200Ah LiFePO4 handles basic RV overnight use with 68% capacity remaining. You could go 3 nights without recharging.
Off-Grid Cabin (Full Day)
ModerateOne 200Ah battery handles a moderate cabin day but needs daily solar recharging. Two 200Ah batteries in parallel give a comfortable 2-day buffer.
Emergency Power Outage Kit
ConservativeFor essentials-only emergency use, a 200Ah LiFePO4 provides nearly a week of power without any recharging.
200Ah vs 100Ah: When to Upgrade
If you already have a 100Ah battery, here's the exact difference a 200Ah makes.
| Scenario | 100Ah LiFePO4 | 200Ah LiFePO4 |
|---|---|---|
| Usable energy | 1,280Wh | 2,560Wh |
| 12V fridge runtime | 28 hours | 57 hours |
| CPAP (no hum.) nights | 5 nights | 10+ nights |
| RV overnight (basic) | 1.5 nights | 3 nights |
| Emergency kit (essentials) | 2.5 days | 5.5 days |
| Weight (typical) | 23 lbs | 45 lbs |
| Price range | $100-180 | $180-320 |
| Cost per Wh | $0.08-0.14 | $0.07-0.13 |
Upgrade to 200Ah if any of these apply: you need more than one night without charging, you run a fridge or freezer, you want emergency power for 3+ days, or you plan to add more loads later. A single 200Ah battery is also cheaper per Wh than two 100Ah batteries and uses fewer cables and connections.
For detailed 100Ah runtime tables, see our How Long Will a 100Ah Battery Last? guide.
LiFePO4 vs AGM: The Usable Energy Gap
A "200Ah" AGM and a "200Ah" LiFePO4 have the same label but deliver vastly different real-world runtime. This is the single most important thing to understand about battery sizing.
| Feature | 200Ah LiFePO4 | 200Ah AGM |
|---|---|---|
| Usable energy | 2,560Wh | 1,200Wh |
| Depth of discharge | 100% | 50% |
| 12V fridge runtime | 57 hours | 26 hours |
| Cycle life | 3,000-5,000 | 300-500 |
| Weight | ~45 lbs | ~110 lbs |
| Price | $180-320 | $150-250 |
| Cost per usable Wh | $0.07-0.13 | $0.13-0.21 |
The LiFePO4 costs slightly more upfront but delivers 2.1x the usable energy, lasts 10x longer, and weighs less than half. For a deep dive into the cost-per-cycle math, see our LiFePO4 vs AGM comparison.
Frequently Asked Questions
How long will a 200Ah battery run a fridge?
A 200Ah LiFePO4 battery runs a standard residential fridge (150W average with compressor cycling) for about 17 hours. A 12V camping fridge (40-50W) lasts 2-3 days. An energy-efficient chest freezer (30-40W average) can run for 3+ days on a single charge.
Is a 200Ah battery enough for an RV?
For basic RV use (LED lights, phone charging, water pump, 12V fridge), a single 200Ah LiFePO4 battery is enough for 1-2 days without recharging. If you run an inverter for a TV, microwave, or coffee maker, you will need solar panels or shore power to recharge daily. Two 200Ah batteries give a comfortable 2-3 day buffer.
How long will a 200Ah battery last at 1000 watts?
A 200Ah LiFePO4 battery at 12V provides 2,560Wh. At 1,000W continuous draw (accounting for ~85% inverter efficiency), you get about 2.2 hours of runtime. At 48V (same 200Ah), you get 9,600Wh and roughly 8.2 hours at 1,000W.
What is the difference between 100Ah and 200Ah battery runtime?
A 200Ah battery lasts exactly twice as long as a 100Ah battery at the same load. A 100Ah LiFePO4 gives you 1,280Wh and a 200Ah gives you 2,560Wh. For example, a 100Ah runs a 50W load for 25.6 hours while a 200Ah runs the same load for 51.2 hours.
How many solar panels to charge a 200Ah battery?
Two 100W solar panels (or one 200W panel) will charge a fully depleted 200Ah LiFePO4 battery in about 6 hours of good sun. A single 100W panel takes about 12 hours (almost 2 full sunny days). For daily cycling of 50% depth, one 200W panel is sufficient in most climates.
Methodology & Sources
Runtime calculations use the formula: Runtime = Usable Wh / Device Watts. LiFePO4 usable energy calculated at 12.8V nominal with 100% DoD. AGM calculated at 12V with 50% DoD to protect battery life. AC device runtimes include 85% inverter efficiency.
- Appliance wattages: EPA Energy Guide labels and manufacturer specifications
- Fridge/freezer cycling: Average 30% compressor duty cycle at 70°F ambient
- Battery pricing: Major retailer pricing as of early 2026 (Amazon, battery direct)
- How Long Will a 100Ah Battery Last? - Runtime tables for the smaller battery size
- Will a 100Ah Battery Run a Fridge? - Deep dive on fridge runtime (double for 200Ah)
- Solar Power for CPAP Machines - Battery sizing for medical device backup
- LiFePO4 vs AGM for Solar Storage - Full cost-per-cycle comparison
This content is for informational and planning purposes only. Always consult a licensed electrician or qualified professional before making electrical installations or purchasing decisions. See our terms of use.