You need the watt-hours your devices will use: label watts × hours ÷ 0.85, and continuous watts at or above the largest single load. A round Wh number on the box is not a plan. That math is our site estimate, not a measured run of your unit.
A phone overnight is a few dozen watt-hours. A car fridge for a night lands closer to 850 on that estimate. An electric kettle fails on output before it fails on capacity — a 1,000 W kettle will not run on a 300 W continuous rating even when the battery still has charge.
What devices should I list first?
The ones you will actually plug in. Use the watts on the device label, not a number from memory. If two things run at once, add the watts. The table below is the same set we use on model runtime pages, so the estimate you make here matches the estimate on a product page.
| Device | Power |
|---|---|
| Small fan | 10 W |
| Phone fast charge | 15 W |
| CPAP | 40 W |
| Car fridge | 60 W |
| Laptop | 65 W |
| Electric kettle | 1000 W |
Example values for estimating. Your label may differ — use that number.
How do I turn watts and hours into watt-hours?
Shop the watt-hours you need: device watts × hours ÷ 0.85. Only about 85% of the printed watt-hours show up as usable AC on our estimate. Runtime the other way is rated watt-hours × 85% ÷ device watts.
A car fridge at 60 W for 12 hours needs about 847 Wh on that math. A CPAP at 40 W for 8 hours needs about 376 Wh. A laptop at 65 W for 4 hours needs about 306 Wh. Size for the set you will run together. A compressor fridge often draws less than its label once it cycles, but we do not credit that here — we have not measured each fridge — so the estimate stays on the high side.
How many watt-hours for a car fridge overnight?
About 847 Wh on our estimate for a 60 W fridge running 12 hours. The Jackery Explorer 300 v2ModelJackery Explorer 300 v28.1 / 10288 Wh · 300 W · 8.16 lb · 3.7 kg · $279.00 and the EcoFlow RIVER 3 PlusModelEcoFlow RIVER 3 Plus8.2 / 10286 Wh · 600 W · 10.4 lb · 4.72 kg · $299.00 sit near 288 Wh and 286 Wh. At 60 W either one estimates about 4.1 hours — not a night.
The Jackery Explorer 1000 v2ModelJackery Explorer 1000 v28.9 / 101,070 Wh · 1,500 W · 23.8 lb · 10.8 kg · $559.00 at 1,070 Wh estimates about 15.2 hours at 60 W. The Jackery Explorer 1500 v2ModelJackery Explorer 1500 v29.0 / 101,536 Wh · 2,000 W · 31.97 lb · 14.5 kg · $849.00 at 1,536 Wh is about 21.8 hours. Those are still estimates. Open a model page if you want the same table with a different device.
| Model | Capacity | Output | Weight | List price | Score |
|---|---|---|---|---|---|
| Jackery Explorer 300 v2 | 288 Wh | 300 W | 8.16 lb · 3.7 kg | $279.00 | 8.1 |
| EcoFlow RIVER 3 Plus | 286 Wh | 600 W | 10.4 lb · 4.72 kg | $299.00 | 8.2 |
| Jackery Explorer 1000 v2 | 1,070 Wh | 1,500 W | 23.8 lb · 10.8 kg | $559.00 | 8.9 |
| Jackery Explorer 1500 v2 | 1,536 Wh | 2,000 W | 31.97 lb · 14.5 kg | $849.00 | 9.0 |
Hours use rated Wh × 85% ÷ 60. Estimate only. List prices as on each model page.
Why isn’t capacity the same as output?
Watt-hours answer how long. Continuous watts answer whether the station will run the device at all. A 1,000 W kettle on a 300 W continuous rating trips protection even when the battery is not empty. Peak watts cover short motor starts, not holding a kettle.
So you need both: enough watt-hours from the formula, and continuous watts at or above the largest single device. For an overnight fridge and a few lights, the best portable power stations for home backupReviewBest Portable Power Stations for Home BackupHome backup picks that list expansion. We looked at capacity and continuous output. A UPS time appears only when the brand lists one. review is a better place to continue than another round number on a retail box.
What should I check before I buy?
- Device list. Watts from the label, hours you need, added if they run at once.
- Watt-hours you need. Watts × hours ÷ 0.85, then compare to the rated Wh on the station.
- Continuous watts. At or above the largest single device. A kettle is an output check, not a capacity check.
Questions
How many watt-hours do I need for a night?
It depends on the device. A 60 W car fridge for 12 hours needs about 847 Wh on our estimate (watts × hours ÷ 0.85). A phone overnight is far less. Size from your devices, not from a round marketing number.
Is 1,000 Wh enough?
For some jobs yes, for others no. At 60 W, about 1,070 Wh (Explorer 1000 v2) estimates near 15 hours. The same battery will not run a 1,000 W kettle if continuous output is under 1,000 W.
Why divide by 0.85?
We treat about 15% of the printed watt-hours as lost to conversion and reserve when estimating AC runtime. It is a site-wide estimate, not a lab measurement of your unit.
Updated 2026-10-04. Runtime uses the same 85% estimate as the model pages. Specs and list prices come from those pages. If a number looks wrong, write through About.
In this note
Open a review or a model page for the score and the specs.
Models 4
- ModelJackery Explorer 300 v28.1 / 10 · 288 Wh · 300 W · 8.16 lb · 3.7 kg · $279.00
- ModelEcoFlow RIVER 3 Plus8.2 / 10 · 286 Wh · 600 W · 10.4 lb · 4.72 kg · $299.00
- ModelJackery Explorer 1000 v28.9 / 10 · 1,070 Wh · 1,500 W · 23.8 lb · 10.8 kg · $559.00
- ModelJackery Explorer 1500 v29.0 / 10 · 1,536 Wh · 2,000 W · 31.97 lb · 14.5 kg · $849.00
An editor chooses what is listed, fact check matches specs and prices to the source, and a page editor reads the page and handles corrections. About
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