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Cooling - 70W running - 1.5x start-up surge

How long can an inverter battery run a Ceiling Fan?

A Ceiling Fan draws about 70W, so a 150Ah 12V tubular battery runs one of them for roughly 9 hours on its own. That comes from 630Wh usable energy divided by 70W. A standard 1200mm induction-motor ceiling fan at medium-to-high speed.

What a Ceiling Fan actually draws

A standard 1200mm induction-motor ceiling fan at medium-to-high speed. The 70W figure used across this page is a typical mid-range Indian retail unit — check the nameplate on yours and put the real number into the calculator, because a 10W difference on an appliance you run for six hours is 60Wh out of a budget of only a few hundred.

Category: Cooling. People search for this as fan, ceiling fan watts, pankha — all the same question, and all answered by the same arithmetic.

Runtime on every standard battery size

Usable energy is Ah x 12V x 0.7 efficiency x 0.5 depth of discharge. Divide that by the appliance draw and you have the runtime with nothing else connected.

One Ceiling Fan on each standard battery size
BatteryUsable energyRuntime with one unitRuntime with two
100Ah420Wh6 hours3 hours
120Ah504Wh7 hours 12 minutes3 hours 36 minutes
135Ah567Wh8 hours 6 minutes4 hours 3 minutes
150Ah630Wh9 hours4 hours 30 minutes
165Ah693Wh9 hours 54 minutes4 hours 57 minutes
180Ah756Wh10 hours 48 minutes5 hours 24 minutes
200Ah840Wh12 hours6 hours
220Ah924Wh13 hours 12 minutes6 hours 36 minutes
250Ah1050Wh15 hours7 hours 30 minutes

How many you can run at once

Nothing stops you connecting more units — the limit is runtime, not the inverter, until you hit the surge ceiling below.

How many Ceiling Fan units a 150Ah battery carries
QuantityContinuous drawRuntimeBand
170W9 hoursLow load
2140W4 hours 30 minutesModerate
3210W3 hoursModerate
4280W2 hours 15 minutesModerate
5350W1 hour 48 minutesHigh load
6420W1 hour 30 minutesHigh load

Duty cycle: the input most calculators ignore

Very few appliances run flat out for a full hour. A fridge compressor cycles, a mixer runs in bursts, a pump fills a tank and stops. Battery Buddy asks for minutes run per hour and multiplies the wattage by that fraction — which is why its answers are usually longer, and more honest, than a calculator that assumes continuous draw.

Duty cycle changes everything
Minutes run per hourAverage hourly drawRuntime on a 150Ah battery
15 min17.5W36 hours
30 min35W18 hours
40 min46.7W13 hours 30 minutes
45 min52.5W12 hours
60 min70W9 hours

Start-up surge and inverter overload

This is a surge-sensitive appliance. Battery Buddy applies a 1.5x start-up multiplier to a Ceiling Fan, so one unit spikes to about 105W for a second or two at switch-on. Your inverter has to survive everything else already running plus that spike — not just the average load.

Peak demand = total continuous load + the single largest start-up surge. The sizing advisor runs that check automatically for whatever mix you enter.

Real setups that include a Ceiling Fan

These are complete household and shop profiles we model, each with its own worked page.

Load profiles containing a Ceiling Fan
ProfileAverage drawBackup on a 150Ah battery
2 ceiling fans + 3 LED bulbs167W3 hours 46 minutes
1 ceiling fan + 2 LED bulbs88W7 hours 10 minutes
3 ceiling fans + 5 LED bulbs255W2 hours 28 minutes
2 fans + 4 lights + TV + WiFi router246W2 hours 34 minutes
Refrigerator + 2 fans + 4 LED bulbs276W2 hours 17 minutes
Laptop + WiFi router + 1 fan + 2 lights163W3 hours 52 minutes
2 fans + 6 lights + TV + refrigerator + WiFi404W1 hour 34 minutes
4 tube lights + 2 fans + billing computer420W1 hour 30 minutes
1 fan + 2 lights + 2 mobile chargers98W6 hours 26 minutes
TV + set-top box + 2 fans + 3 lights242W2 hours 36 minutes

Frequently asked questions

How many watts does a Ceiling Fan use?

About 70W while running. A standard 1200mm induction-motor ceiling fan at medium-to-high speed. Always confirm against the nameplate rating on your own unit before sizing a battery around it.

How long will a 150Ah battery run a Ceiling Fan?

Roughly 9 hours with nothing else connected: 630Wh usable divided by 70W. Add anything else to the inverter and that time drops proportionally.

Does a Ceiling Fan have a start-up surge?

Battery Buddy applies a 1.5x multiplier, so a single unit peaks near 105W at switch-on before settling to 70W. That spike, not the running load, is what trips undersized inverters.

Can I run a Ceiling Fan on a 100Ah battery?

Yes — one unit runs about 6 hours on a 100Ah 12V battery at 70% efficiency. Whether that is enough depends on how long your outages actually last and what else shares the inverter.

Why is my real runtime shorter than this?

The figures assume 70% system efficiency. An older battery, low electrolyte, corroded terminals or thin cabling all reduce the effective factor. Measure yours with the efficiency estimator and re-run the numbers — it takes one discharge test.

Battery Buddy is free, needs no sign-up, sells no batteries and shows every formula it uses. It is built by Flocci Technologies, an India-first AI-native software studio behind 30+ apps that share one Flocci identity.