What size power station do you need during a power cut?
Start with the devices and hours you need, then check output and the exact South African product version separately.
Allow for conversion losses and unused battery reserve, then check continuous output, starting surge and connections separately. A capacity calculation does not establish compatibility.
See why this fitsIllustrative nominal capacity for a 50W load
W × hours ÷ efficiency ÷ usable share = required WhUse the row closest to your situation. The explanation below shows what can move the result.
Comparison table
| Duration | Energy used by the device | Nominal capacity needed |
|---|---|---|
| 2 hours | 100 Wh | About 131 Wh |
| 4 hours | 200 Wh | About 262 Wh |
| 8 hours | 400 Wh | About 523 Wh |
Planning estimate only. Real runtime varies with temperature, load behavior, battery condition and conversion path.
Use your own watts, hours and reserve.
A realistic input gives you a useful range instead of a false promise.
Open Power Planner →What does this mean
for your choice?
Keep watts and watt-hours separate
Watts describe power; watt-hours include time. The table calculates watts × hours ÷ 0.85 ÷ 0.90, assuming zero station idle draw. Add the station's idle draw to the device load when known. A laptop adapter's maximum rating is not necessarily its average consumption.
Treat a local listing as a specification example
The cited EcoFlow South Africa RIVER 3 (UPS) page lists 245Wh with 300W continuous output. The same page also sells the standard RIVER 3, whose switchover time differs, so the exact variant matters. These facts are a specification example, not a recommendation, stock or price promise, or evidence that every similarly named imported model is equivalent.
Plan the whole connection
Read the input rating on your appliance and the output specification for the exact station. Confirm frequency, socket, cable and any grounding requirements. South African mains is 230V at 50Hz, usually through SANS 164 sockets. An English-language listing may still be a US 120V model or ship from the US. Check the version sold to your South African address.
Check the complete power path.
A large enough battery can still be the wrong setup when its output, cable or regional version does not match.
- Measured load and required duration
- Continuous output and starting surge
- Appliance and station voltage/frequency
- Actual sockets, cables and grounding
- Exact model, delivery and warranty
Practical answers
Does more Wh mean it can run any appliance?
No. Wh describes energy. Check running and starting watts, voltage, frequency and connections separately.
Are the table values measured runtimes?
No. They are calculations assuming 85% efficiency, 10% unused reserve and no station idle draw. Replace those assumptions with your own values.
Evidence and sources3 official sourcesShow sources
Separate documented specifications from calculated matches.
Products lists stations documented on EcoFlow South Africa product pages beside source-region technical references. A calculated match is not a compatibility guarantee, a stock or price claim or a purchase recommendation. Enter your actual device load and check the sockets, lead and instructions of the exact unit.