guide · energy
Portable Power Station Runtime Chart (300–3,600 Wh)
Updated October 30, 2026 · 6 min read
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At a 90% depth of discharge and 88% inverter efficiency, a 1,000 Wh station delivers 792 usable Wh. That is 52 h 48 m of phone charging, 22 h 38 m of Wi-Fi, 14 h 24 m of laptop use, 10 h 34 m of refrigerator cycling — or just 1 h 03 m of a space heater. Same box, six very different answers.
Every runtime claim you have read is this one table with different assumptions. Here are the hours for each common capacity, the loads behind them, and what moves the numbers.
The runtime chart
Each cell is usable watt-hours ÷ (device average + 5 W standby), rounded to the nearest minute. The capacities cover the portable market from a small camping unit to a large home-backup station.
| Device (average load) | 300 Wh | 500 Wh | 1,000 Wh | 2,000 Wh | 3,600 Wh |
|---|---|---|---|---|---|
| Phone charger (10 W) | 15 h 50 m | 26 h 24 m | 52 h 48 m | 105 h 36 m | 190 h 05 m |
| Wi-Fi router (30 W) | 6 h 47 m | 11 h 19 m | 22 h 38 m | 45 h 15 m | 81 h 28 m |
| Chest freezer (40 W) | 5 h 17 m | 8 h 48 m | 17 h 36 m | 35 h 12 m | 63 h 22 m |
| Laptop (50 W) | 4 h 19 m | 7 h 12 m | 14 h 24 m | 28 h 48 m | 51 h 50 m |
| CPAP with humidifier (60 W) | 3 h 39 m | 6 h 06 m | 12 h 11 m | 24 h 22 m | 43 h 52 m |
| Full-size refrigerator (70 W) | 3 h 10 m | 5 h 17 m | 10 h 34 m | 21 h 07 m | 38 h 01 m |
| LED TV, 55 in (100 W) | 2 h 16 m | 3 h 46 m | 7 h 33 m | 15 h 05 m | 27 h 09 m |
| Space heater (750 W average) | 0 h 19 m | 0 h 31 m | 1 h 03 m | 2 h 06 m | 3 h 47 m |
Usable energy: 300 Wh → 237.6 Wh, 500 → 396, 1,000 → 792, 2,000 → 1,584, 3,600 → 2,851.2 Wh. A 300 Wh unit yields 237.6 Wh usable once 90% depth of discharge and 88% inverter efficiency are applied.
Read the columns, not the rows. Doubling the capacity doubles every runtime, because the arithmetic is a straight division with no efficiency cliff. The interesting variation is between devices: the ratio between the phone and the heater is 75 to 1, and that is entirely the load, not the battery.
How to read the chart
Three assumptions sit inside every cell:
- 90% depth of discharge. The station uses 90% of its nameplate capacity before the battery management system stops it. LiFePO4 is the chemistry this suits.
- 88% inverter efficiency. The AC outlet keeps 88% of the energy it converts; the rest becomes heat. Published figures run 85–90%.
- Device averages, not nameplate watts. A refrigerator rated at 700 W draws that only while its compressor runs — roughly 10% of the time — for an average near 70 W. A TV draws its rating continuously.
That last point is the one most runtime claims skip. A 700 W fridge looks impossible for a 1,000 Wh station until the duty cycle is applied; a 1,500 W heater looks fine until you notice its thermostat still averages 750 W. The watt-hour explainer covers the unit maths behind the table, and the runtime calculator applies duty cycles automatically.
What moves the numbers
Change the chemistry or the inverter and the whole table shifts. The capacity stays the same; the usable energy does not.
| Chemistry | Depth of discharge | Usable from 1,000 Wh | Space heater runtime (755 W) |
|---|---|---|---|
| LiFePO4 | 90% | 792 Wh | 1 h 03 m |
| NMC lithium | 85% | 748 Wh | 0 h 59 m |
| Lead-acid | 50% | 440 Wh | 0 h 35 m |
| Inverter efficiency | Usable from 1,000 Wh at 90% DoD | Laptop runtime (55 W) |
|---|---|---|
| 85% | 765 Wh | 13 h 55 m |
| 88% | 792 Wh | 14 h 24 m |
| 90% | 810 Wh | 14 h 44 m |
Check: 765 ÷ 55 = 13.91 h (13 h 55 m); 810 ÷ 55 = 14.73 h (14 h 44 m). NMC 748 ÷ 755 = 0.99 h (0 h 59 m); lead-acid 440 ÷ 755 = 0.58 h (0 h 35 m).
Running several devices at once
Combining loads does not multiply the runtime loss — it adds the averages. A blackout essentials set draws about 125 W once the 5 W standby is included, and a work-from-home set about 130 W:
| Load set | Average draw | 1,000 Wh | 2,000 Wh | 3,600 Wh |
|---|---|---|---|---|
| Blackout essentials — fridge 70 W, router 30 W, LED bulb 10 W, phone 10 W, 5 W standby | 125 W | 6 h 20 m | 12 h 40 m | 22 h 49 m |
| Work from home — laptop 50 W, monitor 25 W, router 30 W, LED bulb 10 W, phone 10 W, 5 W standby | 130 W | 6 h 06 m | 12 h 11 m | 21 h 56 m |
A 1,000 Wh station will not carry the essentials set for a full day. That is the useful conclusion of the table: capacity has to be sized against the hours you need, not against the devices alone. The sizing guide runs that calculation in four steps.
Why the space heater row is the warning
Two separate limits show up in that last row. The first is energy: 750 W average against 792 usable Wh is a little over an hour, no matter how large the battery looks on the shelf. The second is output: many 1,000 Wh stations are rated below 1,500 W continuous, so the heater trips the inverter in seconds with the battery still nearly full. Watt-hours decide how long a load runs; the continuous rating decides whether it runs at all.
Motors add a surge on top. A full-size refrigerator may run at 700 W but start at about 2,200 W, so the station needs a surge rating above that figure. If the meter in the calculator crosses 100%, the answer is a smaller load or a bigger inverter — not a bigger battery.
try it with your numbers
Portable Power Station Runtime Calculator
Pick your capacity and devices and get hours to the minute, with duty cycles, chemistry, inverter losses and standby draw already handled. Nothing leaves your browser.
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Frequently Asked Questions
The three questions the chart gets asked most often.
How long will a 1,000 Wh power station last?
It delivers about 792 Wh of usable energy at the default 90% depth of discharge and 88% inverter efficiency. Alone, a phone charger runs 52 hours 48 minutes, a Wi-Fi router 22 hours 38 minutes, a laptop 14 hours 24 minutes, a 55-inch TV 7 hours 33 minutes and a refrigerator averaging 70 W about 10 hours 34 minutes.
How long will a 2,000 Wh power station run a refrigerator?
About 21 hours 7 minutes. A full-size refrigerator averages around 70 W after its duty cycle is applied, and 2,000 Wh × 0.90 × 0.88 = 1,584 usable Wh; 1,584 ÷ (70 + 5) = 21.12 hours. In a hot garage the duty cycle rises and the real figure falls.
Why does a space heater drain a power station so fast?
Because it is a continuous resistive load with almost no duty-cycle relief. A 1,500 W heater averages about 750 W on its thermostat, so a 1,000 Wh station lasts 792 ÷ 755 = 1.05 hours. Many 1,000 Wh units also have a continuous output below 1,500 W, so the inverter trips before the battery is flat.