The best portable power stations for camping in 2025: Expert tested and reviewed

To figure this out, you're going to need to get a pencil and do some back of the envelope calculations.  

You're going to need a couple of bits of information.

First, you need to know what devices you are going to power. List them all, because forgetting that coffee pot or heated blanket could make the difference between the power station lasting all day, or giving up the ghost on you before the day is over.

Specifically, you want to know how much power, in watts, each device draws. This information is usually found on a label on the device. For example, a heater might draw 1,000W, while a CPAP machine might draw 60W. This figure represents the maximum power consumption, and you will find that the power consumption of some devices, such as CPAP machines, fluctuates greatly, while for other devices, like the heater, the power consumption remains quite stable.

Next, you need to know how long you plan on running your devices during a day (or between recharges of your power station). Your heater might run for two hours, while the CPAP machine could run for eight hours.

Power station capacities are measured in watt-hours (Wh). A device drawing 1,000W running for one hour uses 1,000Wh. Therefore, the same device running for two hours will need 2,000Wh. Heaters are some of the most power hungry devices that people find themselves needing to run!

Similarly, a CPAP machine that uses 60W will consume 60Wh per hour, so running it for eight hours would consume 480Wh.

Your total energy usage over 24 hours would then be 2,480Wh.

Based on this, you might think that a 2,500Wh capacity power station would be sufficient. However, in reality, nothing is perfect, and there are energy losses in the system. The rule of thumb is to add 20% to your total and then round up to the next highest capacity available. So, you'd be looking at a power station with a capacity of around 3,000Wh to ensure you have enough stored power for the day.