What Size Power Station Do You Need to Run a Refrigerator? Wattage and Runtime Guide
If your goal is to keep food safe during an outage, your refrigerator (and freezer) is usually the first load to plan around. One extended blackout can spoil a full fridge/freezer and wipe out hundreds of dollars in groceries. This is not a place to “buy the bare minimum.”
The good news: sizing a power station for a refrigerator comes down to two practical targets: inverter watts (W) for the compressor start-up moment, and battery watt-hours (Wh) for the hours you want it to run. You can get very accurate by measuring your fridge, but you can also make a solid choice with realistic ranges.
Quick sizing answer (with real-world ranges)
Inverter (W): For most modern full-size refrigerators, plan on at least 500W continuous inverter power. For a more comfortable “don’t worry about it” choice, especially for oversized or older refrigerator models, aim for 1,000W.
Battery (Wh): A typical full-size fridge often uses about 1–2 kWh per day (that’s 1,000–2,000Wh), but real usage can swing a lot with temperature (both ambient air temp and fridge temp settings), door openings, and the contents of the fridge. These are practical planning targets:
| Runtime goal | Battery target (Wh) | What this assumes |
|---|---|---|
| ~8 hours | 800–1,000Wh | Typical fridge cycling, minimal door opening |
| Overnight (~12 hours) | 1,000–1,500Wh | More cushion for warmer rooms or frequent use |
| ~24 hours | 1,500–2,500Wh | Planning for tougher conditions + normal household habits |
Want the most accurate number? Put a simple plug-in watt meter on the fridge for 24–72 hours and record its daily kWh usage. That tells you your real Wh needs far better than guessing.
Multi-day outages: Instead of buying an enormous battery, many people get better results by prioritizing recharging, especially solar. If you want the fridge to keep going day after day, plan on adding solar and treating the battery as a buffer.
The heart of fridge sizing: how refrigerators really use power
A refrigerator is a cycling load. It does not pull the same watts all day. Most of the time it’s either off (coasting) or running the compressor for short periods to bring the temperature back down. That’s why fridge sizing has two different targets:
| What you’re sizing for | What it means | Why it matters |
|---|---|---|
| Inverter watts (W) | Handling the compressor start-up “burst” + normal running | If the inverter can’t handle the start-up moment, the fridge may fail to start |
| Battery watt-hours (Wh) | How much energy the fridge uses over time | This determines how long you can run the fridge before you must recharge |
Think of it like a car: watts are how hard you press the gas at a moment in time, and watt-hours are how much fuel you burn over the whole trip. You need enough power to start and run the compressor, and enough energy to keep it going for the hours you care about.
Step 1: Find your fridge’s real-world energy use (best method)
If you want accurate sizing (and less guessing), measure the fridge for 24–72 hours with a plug-in watt meter. The number you’re looking for is the fridge’s kWh per day (or Wh per day). That’s your daily fuel burn.
What to record from the meter:
kWh/day (or the total kWh over your test period ÷ days) and a quick note about conditions: Was it hot? Was the door opened a lot? Was the fridge packed full or mostly empty?
Measuring across a hot day and a normal day gives you a safer “realistic worst case” number.
No meter yet? You can still estimate using the refrigerator’s energy label (kWh/year) or typical ranges. But if you’re building a fridge/freezer backup plan you’re relying on, a watt meter is one of the highest-value tools you can buy.
Step 2: Turn “average watts” into watt-hours (the part most people miss)
Here’s the simplest way to understand the math: if you know the fridge’s average watts, you can estimate energy like this: Watt-hours (Wh) = Average watts (W) × Hours.
The trick is finding average watts for a cycling load. If you don’t have a watt meter, you can get a decent approximation by thinking in two pieces: running watts when the compressor is on, and how often it runs (its duty cycle).
| Concept | Plain-English meaning | Example |
|---|---|---|
| Running watts | What the fridge draws while the compressor is actively cooling | 150W when running |
| Duty cycle | How much of the time it runs (not a constant draw) | Runs ~30% of the time |
| Average watts | Running watts × duty cycle (plus small standby loads) | 150W × 0.30 = 45W avg per hour |
Example (reasonable fridge math):
Let’s say your fridge pulls about 150W when the compressor is running, and it runs about 30% of the time. That’s roughly 45W average. Add a little overhead for electronics/efficiency and call it 55W average (or 55Wh per hour).
If you want 12 hours of runtime: 55W × 12h = 660Wh. Add a safety cushion (door openings, warm room, conversion losses) and plan around 800–1,000Wh.
This is why a fridge can need a decent inverter to start, but still be manageable on battery energy over a normal overnight window.
If you measured with a watt meter and got a daily number, converting is even easier: 1.5 kWh/day = 1,500 Wh/day. For a 12-hour goal, that’s roughly half a day: ~750Wh, then add cushion.
Step 3: Choose an inverter that can start the compressor comfortably
The inverter is about the hard moment when the compressor starts. Many fridges have a brief start-up surge that can be several times higher than the running draw. That surge is short, but if the inverter can’t handle it, the fridge may fail to start (or it may start sometimes and trip other times).
Practical rule: For full-size refrigerator backup, many people start around a ~1,000-1,500W class power station (with strong surge capability) for fridge-only, and move to ~2,000–3,000W class if they want to run other essentials and gain extra confidence for tougher conditions.
The goal isn’t to buy the biggest inverter possible. It’s to avoid sizing so tight that one hot afternoon or one extra door-opening turns into spoiled food. A bit of inverter headroom is usually cheaper than replacing a fridge and freeze full of spoiled food, even once.
Step 4: Pick a battery target that matches your runtime goal (with cushion)
Once you understand your fridge’s average energy use, sizing the battery becomes straightforward: pick a Wh target for your time window, then add margin for real-world conditions and conversion losses.
In practice, many people add ~20–30% cushion for a fridge backup plan they actually want to trust.
| Runtime goal | Planning approach | What usually changes the number |
|---|---|---|
| Overnight (8–12 hours) | Use your measured/estimated Wh for the window + ~20–30% cushion | Hot rooms, frequent door opening, warm groceries added |
| 24 hours | Use measured Wh/day (best) + cushion | Daytime heat and normal household habits |
| Multi-day | Battery + a recharging plan (solar/AC/generator) | Cloudy days, shade, and recharge speed limitations |
If you want to shop by size after you get a target, browse our power station collection here. We highly recommend the PECRON F3000LFP Power Station as a robust yet affordable option to keep your fridge cold and many of your most critical devices running during an outage.
How to make a smaller power station last longer (real-world tactics)
If your power station is sized for overnight or a day of backup, a few simple habits can noticeably extend runtime. These are “free wins” that reduce how hard the fridge has to work.
| What to do | Why it helps |
|---|---|
| Keep doors closed and decide what you need before opening | Every door opening dumps cold air and forces the compressor to run more |
| Add thermal mass (cold water bottles, frozen packs) | More cold “mass” stabilizes temps so the compressor cycles less |
| Move the fridge out of heat if possible (shade / cooler room) | Hot surroundings can dramatically increase energy use |
| Improve airflow behind the unit | Compressors run less when heat can escape efficiently |
| Use a fridge thermometer | Helps you avoid “panic opening” and confirm temps stay safe |
These tactics won’t turn a tiny battery into a multi-day solution, but they can be the difference between “barely made it” and “felt easy.”
Multi-day outages: solar and recharging strategy
If you want refrigerator backup that can go beyond a day, the smartest upgrades are usually about recharging. A bigger battery helps, but it’s a one-time buffer. Solar (and fast AC charging when available) can keep you going day after day.
With solar, think in terms of “daily replacement.” If your fridge uses around 1–2 kWh/day, your solar setup needs to put roughly that much energy back in, plus a bit extra for cloudy hours and conversion losses.
A 200W solar panel can provide about 1,000Wh (1kWh) in a full day of direct sunlight. One or two 200W solar panels is usually enough to cover a refrigerator.
Panel wattage, sun hours, and shade matter a lot, so sizing solar is about reasonable expectations, not perfect math.
Recommended shopping approach
If you want a refrigerator backup setup that feels reliable, aim for a power station that clears your inverter target with breathing room, then choose battery capacity based on your real runtime goal. If you expect longer outages, prioritize solar input and charging speed so the setup can recover instead of just slowly draining.
The fastest way to sanity-check your exact devices and runtime is the quiz, and then you can browse all available options from the collection page.
Conclusion
To run a refrigerator on a portable power station, you need enough inverter watts to handle compressor start-up and enough battery watt-hours to cover the hours you care about. The most accurate way to size it is to measure your fridge’s real energy use with a watt meter for a day or two, because temperature, habits, and fridge condition can change the numbers a lot.
Most importantly, remember the value side: a single outage can spoil an entire fridge and freezer full of food. A little headroom and a realistic charging plan usually costs less than replacing groceries even once.