Solar Fan Calculator
Size solar for ceiling fans — the cheapest solar upgrade for load-shedding.
About the Solar Fan Calculator
If you have ever wanted a fast, reliable Solar Fan Calculator that works on your phone without sign-ups or ads getting in the way, this is it — the figures update the moment you type.
Not every appliance should run on solar — high-wattage, long-running loads drain batteries quickly. This Solar Fan Calculator estimates how long your solar battery can run a specific appliance, so you plan your power priorities during outages and at night.
The calculation divides the battery's usable capacity by the appliance's consumption to give runtime, accounting for the depth-of-discharge limit of the battery type.
The order of priority for most Pakistani homes: fans and lights first, then the fridge (intermittent), then TV and internet, with heavy loads like ACs and heaters only on large systems. This calculator quantifies what each choice costs in battery.
Run the tool for each appliance you plan to power — the numbers will show you quickly why a small battery struggles with an AC but handles fans and lights for many hours.
Come back to the Solar Fan Calculator whenever your numbers change; because everything runs live in your browser, you can re-run it as many times as you need at no cost.
How to estimate solar runtime for an appliance
- 1
Enter the appliance's wattage.
- 2
Enter your battery capacity and system voltage.
- 3
Read the runtime in hours, updated live.
Frequently Asked Questions
Can solar run fans during load-shedding?
Yes — 4 fans × 75 W × 12 h is under 4 kWh/day, so a small 1 kW system with battery keeps fans running through load-shedding.
How long can a solar battery run a fan?
A 70 W fan on a 200 Ah, 12 V battery (2.4 kWh, usable ~1.2 kWh at 50% discharge) runs roughly 15–17 hours. An AC, by contrast, would drain the same battery in under an hour.