THE SIMPLE GUIDE / UK BACKUP POWER
How to choose a
portable power station.
Start with what you need to keep running. Then work out how long you need it. Our calculator turns those choices into an estimated battery size and output requirement.
Build your backupYOUR ESSENTIALS
Choose what stays on.
Press an appliance tile to open it, pick the type and use the + and − buttons to set quantities. Close the tile to keep your choices. Add a custom appliance with the Other tile.
The watts readout estimates the draw if your selected devices run together. Where possible, use the appliance’s actual operating wattage rather than its charger or power-supply rating.
Watts and watt-hours, simply
Watts (W) describe how much power a device draws. Watt-hours (Wh) describe energy: a 50 W device running for four hours uses 200 Wh before losses. A station must have enough output in watts and enough battery capacity in watt-hours.
YOUR TIMEFRAME
Decide how long.
Choose 24, 48 or 72 hours, or enter a custom duration. This is the time without mains power or recharging. It does not mean every appliance runs continuously.
Open Adjust usage assumptions to check daily hours, full phone charges per day and fridge cycling. The battery estimate allows for our stated usable-capacity and conversion-loss assumptions; the output estimate includes a safety margin.
A useful starting point, with limits
Appliance presets include provisional assumptions. Fridge startup, changing loads and inverter idle consumption can affect results. We do not model solar recharging or additional inverter idle load. Check the estimate methodology and source register before relying on a result.
YOUR MATCHES
Compare suitable options.
The calculator checks nominal capacity, continuous output and declared startup surge where needed. It shows up to three qualifying products, or explains when our catalogue has no match. Click a completed step to edit your choices.
Check the exact UK model, sockets, appliance startup requirements and manufacturer guidance before buying. Our catalogue records manufacturer declarations; we have not independently tested the products. Runtime is an estimate, not a compatibility guarantee.
Explore the product catalogue →Portable power station questions, answered.
What size power station do I need?
Add each appliance’s watts multiplied by its running hours to estimate delivered watt-hours. Divide that total by the usable battery fraction and conversion efficiency to estimate nominal capacity. For example, a 50 W load for four hours needs 200 Wh delivered; at 90% usable capacity and 85% efficiency, that is about 262 Wh nominal. These are example assumptions, not measured runtime.
Can a portable power station run a fridge?
Check both energy use and compressor startup against the exact station’s AC output and surge specification. A large battery alone does not establish compatibility. Our fridge defaults are provisional; review the source register and enter appliance-specific values.
Will a 1,000 Wh station last 24 hours?
At an illustrative 90% usable fraction and 85% efficiency, it delivers about 765 Wh: roughly 15 hours at a constant 50 W, before additional inverter idle consumption. Intermittent loads need a daily usage estimate.
Does this calculator include solar charging?
No. It estimates backup without recharging. Solar input varies with equipment, weather, shading and placement and is outside this calculation.
Keep your backup plan simple.
Start with essentials, check the assumptions and leave room for uncertainty. Use portable equipment as its manufacturer directs. This calculator does not assess medical, safety-critical or hardwired equipment.
Try the calculator