UK Sizing Guide
How Much Backup Power Do You Need?
Choose a portable power station by adding the devices that must run together, checking their start-up demand and deciding how long they need to operate. This guide gives you a practical UK sizing method without promising a fixed runtime.
1. List the equipment that matters
Start with essential devices rather than the whole house. Many plans prioritise the router and fibre ONT, phones, LED lighting, a laptop and, where technically suitable, refrigeration or heating controls.
2. Add the simultaneous load
| Equipment | Illustrative planning range | What to check |
|---|---|---|
| Wi-Fi router | 8–12W | Include a separate modem or fibre ONT. |
| LED lamp | 5–10W | Use the actual lamp rating. |
| Laptop | 40–65W adaptor reference | Real draw varies with charging and workload. |
| Television | 40–90W | Check the model label and settings. |
| Refrigerator | Variable cycling load | Confirm running and compressor start-up demand. |
| Phone charging | 5–20W | Include every device charging at once. |
3. Choose enough output and capacity
Continuous output in watts determines what can run together. Battery capacity in watt-hours helps estimate how long those devices may run. Keep reserve for inverter overhead, changing loads, temperature and battery condition.
Compact backup
BLUETTI AC2P
230.4Wh · 300W
For a modest communications, lighting and short laptop setup when the total load remains within its limits.
Everyday backup
BLUETTI AC60P
504Wh · 600W
For a wider selection of carefully checked essentials and more runtime margin than a compact entry model.
Mid-range household backup
EcoFlow DELTA 3
1,024Wh · 1,800W
For larger combined loads and longer planned runtime after all running and start-up requirements have been checked.
Higher-capacity BLUETTI
BLUETTI AC200PL
2,304Wh · 2,400W
For longer support of selected essentials where the larger size, weight and cost suit the plan.
Higher-capacity EcoFlow
EcoFlow DELTA 3 Max
2,048Wh · 2,400W
A higher-capacity alternative for larger combined loads and longer runtime planning.
4. Estimate runtime cautiously
A useful planning formula is battery capacity × efficiency allowance ÷ average load. The result is theoretical. Actual runtime may be shorter because inverter efficiency changes with load, appliances cycle, and temperature and battery condition matter.
For refrigeration, pumps and similar equipment, capacity alone is not enough: the power station must also handle start-up demand.
Typical planning routes
Light essentials
Router, ONT, phones, LED lighting and short laptop use may fit a compact model after the measured load and target hours are checked.
Broader home essentials
Adding refrigeration, more work equipment or overnight coverage usually points towards more capacity and output headroom.
Build your own estimate
Enter the devices you want to run together and your target duration. Treat the result as a planning aid, then confirm the product limits and appliance start-up demand.