Short Answer
For simple outage planning, start with this formula:
watts x hours = watt-hours
If an internet router uses about 12 watts and you want it running for 8 hours, the raw estimate is 96 watt-hours. A portable power station rated at exactly 96 Wh is still too small for that job because real-world runtime is affected by inverter losses, temperature, battery age, and the way each device draws power.
For the calculator, Canada Ready Home uses an 80% usable-capacity planning assumption. That means a 96 Wh raw load becomes a rough 120 Wh battery-capacity target before you add extra margin.
Use the watt-hour calculator for a quick estimate, then come back to this guide for the buying checks and caveats.
Use The Calculator First
The Canada Ready Home watt-hour calculator is designed for small, practical outage loads:
- internet routers and modems
- LED lamps
- phone charging
- laptop charging
- small fans
- radio or communication devices
It is not a whole-home backup calculator. It is also not a guarantee for medical equipment, fridges, freezers, sump pumps, heaters, kettles, microwaves, tools, or anything with a motor or compressor surge.
Why The Calculator Adds A Buffer
Portable power stations do not deliver every rated watt-hour to every device. Inverter losses, temperature, battery age, and device behaviour can reduce usable runtime. Canada Ready Home uses a conservative 80% usable-capacity planning assumption in the calculator.
This is deliberately simple. The goal is to avoid under-sizing small backup loads, not to promise exact runtime.
Example Outage Loads
Use the wattage from your device label, charger, or manual whenever you can. The examples below are only planning placeholders.
| Item | Example watts | Example hours | Raw watt-hours |
|---|---|---|---|
| Internet router | 12 W | 8 hours | 96 Wh |
| LED lamp | 9 W | 6 hours | 54 Wh |
| Phone charging | 15 W | 2 hours | 30 Wh |
| Laptop charging | 45 W | 3 hours | 135 Wh |
In that example, the raw total is 315 Wh. With an 80% usable-capacity assumption, the battery-capacity target is about 394 Wh before adding any extra household margin.
Canada-First Outage Context
The Government of Canada recommends planning ahead for power outages, including emergency kits, household plans, battery packs for critical devices, flashlights, and radios. It also calls out medical planning for devices powered by electricity and recommends talking to a doctor or medical professional about critical medical needs during outages.
That matters for portable power because the right answer is not always "buy a bigger battery." For some households, the first step is a written outage plan, a charged phone battery pack, flashlights, and a clear list of what must stay powered.
What To Check Before Buying
Before you compare portable power stations, write down:
- Device wattage from the label or manual
- Startup surge for appliances with compressors
- Whether the device needs AC, USB-C, or DC output
- Temperature and storage caveats from the manufacturer
- Whether the use case involves medical equipment or safety-critical loads
Then compare that list with the station's rated capacity, continuous AC output, surge output, port types, weight, warranty, and Canadian availability.
For broader product criteria, use the portable power hub and the queued best portable power stations in Canada buyer guide once product validation is complete.
Portable Power Station vs Fuel Generator
Battery power stations and fuel generators solve different problems. The Government of Canada says portable fuel-burning generators should be operated at least 6 m (20 feet) from homes or buildings, with exhaust directed away from doors and windows, and that carbon monoxide alarms should be working.
Battery- or solar-powered portable generators do not produce carbon monoxide during normal use, but they still have capacity and output limits. They are usually better suited to smaller indoor loads like phones, routers, laptops, lights, and selected small devices.
For the safety tradeoffs between battery stations and fuel generators, see the portable power station vs generator guide.
Important Caveat
For medical devices, safety-critical equipment, or appliances with startup surge, verify requirements with the device manual, manufacturer support, or a qualified professional.
For CPAP backup, refrigerated medicine, life-sustaining equipment, or other critical needs, do not rely on a general online calculator alone. Make a power outage plan with the relevant medical, device, or professional support.
FAQ
Is a 300 Wh power station enough for an outage?
It can be enough for small loads like phone charging, a router, and a light for a limited period. It is usually not the right size class for heavy appliances or long fridge backup.
Why does the calculator use 80% usable capacity?
It is a simple planning assumption that leaves room for conversion losses and real-world variation. Some setups may do better or worse. The actual result depends on the station, device, output type, temperature, and battery condition.
Can I run a fridge from a portable power station?
Maybe, but do not size fridge backup from watt-hours alone. Fridges have cycling loads and compressor startup surge, and runtime depends on the fridge model, room temperature, how often the door opens, and the power station's output limits.
Should I buy based only on watt-hours?
No. Watt-hours are only one part of the decision. Check output wattage, surge capability, charging options, weight, warranty, seller, and whether the product is actually available in Canada.
Sources
- Government of Canada: Power outages - Get prepared