What size power station do I need?

Choose what you need it for, tick your devices and say how many hours you use them. We work out the usable capacity, continuous output and surge power you need, and show the batteries in stock that meet it according to their spec sheet.

Camping and vansCool box, lights and phones for a few days away.Power outage at homeFridge, router and lights when the power goes out.CPAP at nightOne or more nights without grid power nearby.Tools and job sitesSaw, drill and chargers where there is no grid power.

How we calculate it

For each device we multiply its power by the hours per day and by the share of time it actually runs (a fridge only runs its compressor part of the time). We add them up and multiply by the days without recharging.

We divide that total by the inverter efficiency, which we take as 85%, and add a 20% reserve for cold weather, cell wear and not draining the battery completely. We compare it with the usable capacity the manufacturer declares, or the nominal one if it does not publish it, and we flag that.

Continuous output is the sum of what runs at the same time. Kitchen appliances and tools count one at a time, the biggest one. Surge power adds what the device with the highest start-up demand draws when it switches on.

We do not recommend batteries with more than three times the capacity you need, because you would pay for and carry capacity you will not use. If a battery is missing a figure we need, such as surge or solar input, we do not count it as a match.

Typical power figures for 120 V household power.