Camping Power Calculator: How Much Battery You Need (2026)
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A camping power calculator only needs to answer one question: how many watt-hours will you use between charges? Everything else follows. This guide gives you the numbers for typical camping loads and the arithmetic to turn them into a battery size that is neither wasteful nor disappointing.
The short answer
Most tent campers need 300–600 Wh for a weekend. Add a 12 V cooler and you are at 1,000–1,500 Wh. Add a CPAP and you want 1,500–2,000 Wh for two nights with margin. Cooking electrically changes the answer entirely — use gas.
What camping gear actually consumes
| Item | Watts | Typical use | Wh/day |
|---|---|---|---|
| Phone charge | 10 | 2 phones, full | ~40 |
| LED lantern / string lights | 8 | 5 hrs | ~40 |
| 12V cooler / fridge | 45 avg | 24 hrs | ~1,080 |
| CPAP, no humidifier | 30 | 8 hrs | ~240 |
| CPAP + heated humidifier | 60–90 | 8 hrs | ~480–720 |
| Laptop | 60 | 3 hrs | ~180 |
| Fan | 20 | 8 hrs | ~160 |
| Electric kettle | 1,200 | 10 min | ~200 |
| Portable induction hob | 1,500 | 30 min | ~750 |
The cooler dominates everything else, which is the central insight of any camping power calculator. One 12 V fridge running around the clock consumes more than every phone, light and laptop combined. If you are bringing one, size for it first and treat the rest as rounding.
Three worked scenarios
Weekend tent camping, no fridge. Phones, lights, a speaker, one laptop charge. Roughly 300 Wh across two days. A 500 Wh unit covers it comfortably with margin for a cold night.
Weekend car camping with a 12 V fridge. Fridge at 1,080 Wh per day plus around 150 Wh of everything else. Two days is 2,460 Wh. That is a 3 kWh unit, or a 2 kWh unit with 100–200 W of solar to top it up during the day.
Two nights with a CPAP and no fridge. 480 Wh for the machine with humidifier, plus 100 Wh of devices. Roughly 1,060 Wh, so a 1.5 kWh unit gives you genuine margin. Never size a medical device to exactly the calculated number — details in the CPAP power guide.
The margin rules
Subtract 15% straight away. Inverter conversion and internal losses mean a 1,000 Wh unit delivers about 850 Wh of usable AC output.
Add 20% for cold. Battery capacity falls in low temperatures. A unit that runs your gear comfortably in July may fall short on a near-freezing October night.
Round up, never down. The cost difference between adjacent sizes is far smaller than the cost of a dead fridge full of food.
Where solar changes the calculation
For trips beyond two nights, solar stops being optional. A 100 W panel returns roughly 400–500 Wh on a good day, which nearly covers a 12 V fridge on its own.
The practical approach for extended camping is a moderate battery plus enough panel to replace daily consumption, rather than a very large battery carrying the whole trip. It is lighter, cheaper and open-ended. Bear in mind that trees are the enemy — a shaded campsite may return a fraction of rated output, so plan for less than the ideal figure.
For appliance consumption references, the ENERGY STAR database is the authoritative source. See also watt-hours explained for the underlying method.
Using the camping power calculator for group trips
Group camping changes the arithmetic in a way that catches people out, because consumption does not scale the way you expect. Lighting and the cooler serve everyone regardless of headcount, so those figures stay flat. Device charging is what multiplies.
Four people with a phone each, two with tablets, someone with a camera battery and a portable speaker running most of the evening comes to roughly 250–350 Wh per day on top of your shared loads. Run that through the camping power calculator alongside a 12 V cooler and a two-night trip lands near 3 kWh — a considerably larger unit than any individual would have bought.
The practical answer is usually two mid-sized units rather than one large one. Two people carrying 1.5 kWh each is easier than one person carrying 3 kWh, you get redundancy if one fails, and you can leave one at camp while the other travels with the group. Bear in mind that separate units cannot pool their output, so any single appliance still needs one unit rated to run it.
Agree in advance who charges what and when. The most common group camping failure is not undersizing — it is six people treating one battery as unlimited on the first evening and finding it empty by the second morning.
Frequently asked questions
Can I cook with a power station while camping?
You can, but the arithmetic rarely favours it. A single induction cooking session uses more energy than everything else you will run all weekend. Gas is dramatically more efficient for heat. Reserve electric cooking for a kettle or a quick reheat.
Is a 12V fridge better than a cooler with ice?
For trips beyond two or three days, usually yes — no ice runs, no soggy food, and stable temperature. But it means committing to roughly 1 kWh per day of battery capacity. For a single weekend, ice is often simpler and cheaper.
Should I charge from my car instead?
A 12 V socket typically supplies only 100–120 W, so it is slow, and it requires running the engine or risking a flat starter battery. Useful as a top-up while driving between sites, but not a primary charging plan.
How do I measure my own gear before a trip?
Use a plug-in energy meter at home for a full day of typical use and read the kilowatt-hour total. That measured figure beats every estimate in this or any other table, because it reflects your actual equipment and habits.
Last updated: July 20, 2026. Consumption figures are typical averages; measure your own equipment for accurate planning.
