What size power station do I need?
You need a power station whose battery holds your day's use divided by 0.85, whose rated output covers everything running at once, and whose surge rating covers the biggest motor start. For a fridge, three LED bulbs and a phone through a 24-hour outage, that works out to about 1,725 Wh of battery, 771 W of output and 2,946 W of surge: a 2,000 Wh class station.
| What you want to power | Battery you need | Station class |
|---|---|---|
| Wi-Fi router for an 8-hour workday [41][49] | about 169 to 282 Wh | 300 Wh |
| Full-size fridge for 24 hours [41][42][43][44] | about 1,468 Wh | 1,500 Wh |
| Fridge, 3 LED bulbs, a phone for 24 hours [41][42][43][44][45][46][47] | about 1,725 Wh | 2,000 Wh |
| Fridge and chest freezer for 24 hours [41][42][43][44][48] | about 2,174 Wh | 3,000 Wh |
Every row is worked out below from sourced appliance figures. Try your own list in the runtime calculator.
What three numbers decide the size?
Rated output, surge and battery capacity. A station has to pass all three: a big battery is no help if the output can't carry the load.
- Rated output (W). Add the running watts of everything that will be on at the same time. The station's continuous AC rating has to be higher, or it shuts off.
- Surge (W). Motors and compressors (fridges, freezers, pumps, air conditioners) draw several times their running watts for a moment when they start. The station's published surge rating has to cover that peak.
- Battery (Wh). Add up the energy you need: watts x hours for each device. Divide by the inverter efficiency, 0.85 unless the maker publishes a figure, to get the battery size.
The formula behind every runtime on this site is runtime = Wh x efficiency / load W. Sizing runs it backwards: battery Wh = energy needed / efficiency. How we got these numbers.
How do I size a station for a 24-hour outage?
Add up a day of use, then divide by 0.85. Here is the worked example from our 24-hour fridge outage page.
| Device | Watts | Hours | Energy |
|---|---|---|---|
| Full-size fridge (average draw) [41][42][43][44] | 52 W | 24 | 1,248 Wh |
| 3 LED bulbs (8.8 W each) [45] | 26.4 W | 6 | 158.4 Wh |
| Phone charger [46][47] | 20 W | 3 | 60 Wh |
| Total [41][42][43][44][45][46][47] | 1,466.4 Wh |
Battery needed: 1,466.4 / 0.85 = about 1,725 Wh.
Where the watts come from: the fridge's 52 W is the median ENERGY STAR full-size model (457 kWh a year / 8,760 hours). The bulb is a Philips 8.8 W A19 LED, the 60 W equivalent. The phone charger is Apple's 20 W USB-C adapter at its rated output, a ceiling rather than a typical draw. All three are on the appliances list with their sources.
Which stations cover that day?
In our data, these stations hold enough usable energy for the full 1,466.4 Wh day and pass the output and surge checks:
- Anker SOLIX S2000 (2,010 Wh, 0.9 published efficiency): about 1,809 Wh usable, 29 hours
- Jackery Explorer 2000 v2 (2,042 Wh): about 1,736 Wh usable, 28 hours
- Anker SOLIX C2000 Gen 2, DJI Power 2000, EcoFlow DELTA 3 Max and DELTA 3 Max Plus (2,048 Wh each): about 1,741 Wh usable, 28 hours
Larger stations, from the BLUETTI Apex 300 (2,764.8 Wh) up to the Jackery Explorer 5000 Plus (5,040 Wh), cover the energy with room to spare. The BLUETTI Elite 200 V2, Elite 300 and Elite 400 also hold enough, but BLUETTI doesn't publish their surge, so the fridge start can't be confirmed. A 1,500 Wh class station gets you about 20 to 21 hours of the same day.
What output and surge does that day need?
About 771 W running and about 2,946 W at the moment the fridge starts. For the output check we use the fridge's highest running figure, 725 W (Virginia Cooperative Extension), plus 26.4 W of bulbs and 20 W of phone: 771.4 W.
For the start, Generac's chart puts a fridge at 2,900 W, which is 2,175 W above its 725 W running figure. Add that jump to the 771.4 W already running and the peak is 2,946.4 W. Every station listed above has a published surge at or above that, except the DJI Power 2000, which publishes no surge figure but is rated 3,000 W continuous, enough on its own.
Why does rated output matter more than battery size?
Because a station that can't carry the load shuts off, however much energy it stores. Running watts decide whether it works at all; watt-hours decide how long.
A fridge shows this well. Its average draw is only 52 W, so even a 286 Wh EcoFlow RIVER 3 Plus holds enough energy for about 4.6 hours of it on paper (286 x 0.85 / 52). But generator charts put a fridge at 700 to 725 W running, and the RIVER 3 Plus is rated 600 W, so it can't run one. Check output and surge first, then size the battery.
What sizes do power stations come in?
In our list of 38 stations, batteries run from 286 Wh to 5,040 Wh. They fall into rough classes:
| Class | Battery range | Rated output range | Examples |
|---|---|---|---|
| 300 Wh [9][10][18][19][20] | 286 to 297 Wh | 350 to 600 W | Goal Zero Yeti 300, EcoFlow RIVER 3 Plus |
| 500 Wh [20][21][22][23][24] | 499 to 677 Wh | 500 to 1,000 W | Goal Zero Yeti 500, DJI Power 500 |
| 1,000 Wh [2][3][4][5][6][11] | 998 to 1,264 Wh | 800 to 2,200 W | EcoFlow DELTA 3 Plus, Jackery Explorer 1000 v2 |
| 1,500 Wh [7][8][27][28] | 1,505 to 1,536 Wh | 1,800 to 2,000 W | Jackery Explorer 1500 v2, Anker SOLIX F1500 |
| 2,000 Wh [12][14][15][17][34][35][36] | 2,010 to 2,074 Wh | 1,500 to 3,000 W | Jackery Explorer 2000 v2, EcoFlow DELTA 3 Max |
| 3,000 Wh and up [31][32][33][37][38] | 2,765 to 5,040 Wh | 2,400 to 7,200 W | Anker SOLIX F3000, EcoFlow DELTA Pro 3 |
The stations list has every model with its published capacity, output and surge.
How do I size for small electronics?
Small loads need little output, so the battery decides. A Wi-Fi router draws 18 to 30 W by NETGEAR's adapter ratings. Over an 8-hour workday that is 144 to 240 Wh, and dividing by 0.85 gives about 169 to 282 Wh of battery: a 300 Wh class station.
A laptop on a 35 to 70 W adapter (Apple's MacBook Air range, a ceiling rather than a typical draw) uses at most 280 to 560 Wh over 8 hours. Add the router and you are in the 500 Wh to 1,000 Wh class.
How do I size for a fridge and a freezer?
Both together average about 77 W, so 24 hours takes about 2,174 Wh of battery, and starting one while the other runs needs about 3,625 W of surge. The full breakdown is in what size solar generator runs a refrigerator and freezer.
How much bigger should I go than the math says?
Some margin is sensible, because the math is a best case. Batteries hold less as they age and in the cold, most stations keep a small reserve, and your appliances may draw more than the published figures. A plug-in watt meter on your own devices gives you the best inputs.
If you can recharge during the day, from the wall or solar, you can buy a smaller station. If you can't, size for the whole outage.
What should I read next?
Quick answers
What size power station do I need for a fridge during an outage?
For a full day, about 1,468 Wh of battery for the fridge alone (52 W average x 24 hours / 0.85), or about 1,725 Wh with three LED bulbs for 6 hours and a phone. The station also needs about 725 W of rated output and up to 2,900 W of surge to start the fridge.
How do I calculate what size power station I need?
Add the running watts of everything that runs at once and pick a station rated above that. Check its surge rating covers the largest motor start. Then add up watt-hours (watts x hours for each device) and divide by 0.85 to get the battery size.
Is a 1,000 Wh power station enough?
It runs a full-size fridge for about 16 to 18 hours, or a laptop and a Wi-Fi router through an 8-hour workday (about 499 to 941 Wh of battery). A full day of a fridge, three LED bulbs and a phone takes about 1,725 Wh, so it falls short.
What is the difference between watts and watt-hours on a power station?
Watts (rated output) is how much power the station can deliver at once, which decides what it can run. Watt-hours (battery capacity) is how much energy it stores, which decides how long it runs.