Box fan: how much battery you need
Box fan draws about 120 W (50–200 W range), runs 100% of the time and uses 960 Wh per day. Start-up surge: 200 W.
A box or window fan on its lowest speed draws a fraction of its rating. Champion lists 50–200 W running; we use the middle for energy and the top starting figure (200 W) for the peak.
Battery needed
| Hours | Wh | Battery (Wh) | Inverter (W) |
|---|---|---|---|
| For 8 hours | 320 | 485 | 132 / 200 |
| For 24 hours | 960 | 1455 | 132 / 200 |
| For 72 hours | 2880 | 4364 | 132 / 200 |
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Stations that fit (24 h)
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FAQ
How many watts does a Box fan use?
Typically 120 W while running, with a range of 50–200 W depending on model and age. Start-up surge can reach 200 W.
How long will a 1000 Wh power station run a Box fan?
About 5.5 hours on the clock, allowing for the 100% duty cycle, inverter losses and a 20% reserve.
What size power station do I need for a Box fan overnight (8 h)?
About 485 Wh of battery and an inverter rated at least 132 W continuous with 200 W surge.
Can I run a Box fan on solar during an outage?
You need roughly 640 W of panels in winter to replace a day's use (960 Wh), charging through a station with a big enough MPPT input.
Other appliances
1 Approximate values: estimated from motor or heater power and typical figures published online, not from a manufacturer chart. Check your appliance label.
Inverter efficiency 88%, usable depth of discharge 90%, reserve 20%. Full method: How we calculate. source