Portable Power Station Calculator
See exactly what your portable power station can run and for how long. Estimate runtime for camp lights, phones, laptops, mini fridges, CPAP machines, and more using battery watt-hours and device power draw.
Portable Power Station Calculator
Enter your power station capacity and device wattage to estimate runtime, usable energy, and whether your station can handle the device load. Use the quick presets to fill in common appliance wattages instantly.
Calculate Power Station Runtime
This calculator estimates how long a portable power station will run one or more devices based on battery watt-hours, average device power, and inverter efficiency.
Calculation Results
These values show usable battery energy, estimated device runtime, and whether the power station can handle the load based on the entered inverter rating.
Educational Estimates Only: Actual runtime varies with device efficiency, usage patterns, temperature, inverter losses, battery age, and surge requirements. Devices with compressors such as fridges cycle on and off, which extends practical runtime. Always verify against your device's actual wattage label or manual.
What Can a Portable Power Station Run?
Understanding watt-hours and device wattage is the key to matching a power station to your actual needs for camping, home backup, travel, or emergencies.
A portable power station is essentially a large rechargeable battery with built-in AC inverter, USB ports, and DC outputs. The battery stores energy in watt-hours, and every device you plug in consumes that energy at a rate measured in watts. The basic relationship is straightforward: more watt-hours means more runtime, and a lower device wattage means the battery lasts longer.
The runtime formula is simple in principle. You take the station's usable watt-hours, after accounting for inverter efficiency losses of typically 80 to 90 percent, and divide by the device's power draw in watts. A 1000Wh power station with 85 percent efficiency has about 850Wh of usable energy. At 100W draw, that gives roughly 8.5 hours of runtime. At 10W draw for a camp light, the same unit lasts around 85 hours.
Smaller 300Wh units are practical for phone and tablet charging, camp lights, and small electronics. A 300Wh unit can charge a phone around 20 times or run a laptop for several hours. However, a 300Wh unit is usually not enough to run a mini fridge continuously because the energy would be depleted quickly. A 1000Wh or larger unit is usually the minimum for meaningful fridge backup, and the fridge cycling on and off rather than running continuously helps extend practical runtime.
CPAP machines are a common use case because they typically draw around 30 to 150 watts depending on model, settings, and whether a heated humidifier is used. A 500Wh unit without a humidifier may cover a single night, while longer travel or camping trips often need a 1000Wh or larger unit to provide reliable multi-night coverage.
Inverter rating matters as much as watt-hours. Every power station has a maximum continuous output in watts that limits what it can power. A 300Wh unit with only a 300W inverter rating cannot run a device that needs 500W of startup surge, even though the energy capacity might seem similar to higher-rated units. Always check both Wh and inverter wattage before assuming a device is compatible.
Common device wattages
| Device | Typical Watts |
|---|---|
| Camp light / LED lamp | 5 – 15W |
| Phone charge | 10 – 30W |
| Tablet charge | 20 – 45W |
| Laptop | 45 – 100W |
| Wi-Fi router | 20 – 30W |
| Mini fridge (camping) | 40 – 100W |
| Compact fridge | 100 – 200W |
| CPAP (no humidifier) | 30 – 100W |
| CPAP (with humidifier) | 100 – 200W |
| Box fan | 20 – 65W |
| Coffee maker | 600 – 1200W |
Power station size guide
- Under 300Wh: phones, tablets, camp lights, small electronics.
- 300 – 500Wh: laptops, CPAP for one night, basic camping loads.
- 500 – 1000Wh: CPAP multi-night, mini fridge for several hours, light home backup.
- 1000 – 2000Wh: mini fridge all day, moderate home backup, small appliances.
- 2000Wh+: full-size fridge, power tools, extended home backup.
Why fridges cycle on and off
A mini fridge does not run at full wattage continuously. Its compressor cycles on and off to maintain temperature, which means real-world power draw is often much lower than the peak wattage label. This is why a 1000Wh station can often run a 100W mini fridge for far longer than 10 hours in practice.
Inverter efficiency explained
Portable power stations lose some energy converting stored DC battery power into usable AC output. This efficiency loss is typically around 10 to 20 percent depending on load and unit quality. At 85 percent efficiency, a 500Wh unit delivers about 425Wh of usable energy to your devices.
Surge versus continuous watts
Many devices, especially those with motors or compressors, require a surge of power at startup that can be two to three times the running wattage. Always check the surge rating of your power station against the startup requirement of the device, not just the running wattage.
Solar and recharging
Most modern portable power stations can be recharged via solar panels, car 12V sockets, or AC wall outlets. Adding a solar panel can extend run time indefinitely in sunny conditions, making the setup particularly useful for camping, outdoor events, and extended power outages.
Frequently Asked Questions
These are the most common questions people ask when choosing or using a portable power station for camping, home backup, travel, and emergency use.
How long will a portable power station last?
It depends on the station's watt-hour capacity and the power draw of your devices. Divide usable watt-hours by device watts to get an approximate runtime in hours. A 1000Wh station at 85% efficiency running a 100W load lasts roughly 8.5 hours.
Can a portable power station run a fridge?
Yes, if the inverter wattage is high enough to handle startup surge and the battery is large enough to cover the needed runtime. A mini fridge typically needs 40 to 100W running, but may surge to 300 to 400W at startup. A 1000Wh or larger unit with a 500W+ inverter can usually power a mini fridge for many hours because the compressor cycles on and off rather than running continuously.
Can it power a CPAP machine?
Yes. CPAP machines typically draw 30 to 100W without a heated humidifier and up to 200W with one. A 500Wh station can often cover a single night without the humidifier. For multi-night camping or travel, a 1000Wh or larger unit gives more comfortable headroom.
What does a 300Wh power station run?
A 300Wh station is useful for phones, tablets, laptops, camp lights, and small electronics. At 85% efficiency it delivers about 255Wh, which is enough to charge a phone around 17 times, run a laptop for several hours, or power camp lights through the night.
What does a 1000Wh power station run?
At 85% efficiency a 1000Wh station delivers roughly 850Wh. That can run a mini fridge for 8 to 20+ hours depending on cycling, a CPAP overnight with margin to spare, a laptop for over 13 hours at 65W, or combined smaller loads for a full camping day.
Why is there an efficiency loss?
Power stations convert stored DC battery energy into AC output through an inverter. This conversion is not perfectly efficient and typically loses 10 to 20 percent as heat, depending on load level and inverter quality. Most practical estimates use 80 to 90 percent efficiency.
What is surge wattage and why does it matter?
Surge wattage is the short peak of power some devices draw on startup, often two to three times their running wattage. Devices with motors or compressors, such as fridges, fans, and pumps, can have high startup surges. Your power station must be able to handle that peak, otherwise it may shut down or fail to start the device.
How many phones can a power station charge?
An average smartphone has a battery of around 13 to 18Wh. Using 15Wh as a middle estimate, a 300Wh station at 85% efficiency delivers about 255Wh and can charge around 17 phones. A 1000Wh station can charge around 57 phones from empty.
Can I recharge a power station with solar?
Yes, most modern portable power stations support solar charging via a dedicated solar input port. Solar charging time depends on panel wattage, sunlight hours, and station capacity. This makes them useful for extended camping or off-grid situations where AC power is not available.
Can I run multiple devices at once?
Yes, as long as the combined wattage of all devices does not exceed the station's inverter output rating. Add up the wattage of all devices you plan to run simultaneously and make sure the total stays under the station's continuous output limit.
Is a portable power station the same as a UPS?
Not exactly. A UPS is designed for instant switchover during power failures and is optimised for computers and sensitive electronics. A portable power station prioritises capacity, portability, and versatility rather than instant failover switching. Both can provide backup power, but they are designed for different purposes.
How do I find my device wattage?
Check the label on the device itself, the product manual, or the charger brick. Wattage is usually printed directly on the device or listed in specifications. If you see only volts and amps, multiply them to get watts.
What battery chemistry do portable power stations use?
Most modern portable power stations use either lithium-ion NMC or lithium iron phosphate (LiFePO4) cells. LiFePO4 units typically offer longer cycle life, better thermal stability, and safer operation, while NMC units can be lighter for the same capacity. LiFePO4 is generally preferred for longer-term reliability.
Does temperature affect runtime?
Yes. Cold temperatures reduce battery capacity temporarily, so a power station used in cold weather may deliver noticeably less runtime than it would in moderate conditions. Very high temperatures can also reduce performance and shorten battery life over time.
Should I fully discharge before recharging?
No. Lithium batteries do not have memory effects and actually prefer partial cycles over deep discharges. For best long-term health, avoid regularly discharging all the way to zero and try to keep the battery within a moderate charge range when storing for extended periods.
Can a portable power station run a coffee maker?
A standard coffee maker typically uses 600 to 1200 watts. A power station with a 1000W or higher inverter rating and at least 500Wh capacity can make a single pot of coffee. However, the brew cycle depletes a large portion of a smaller battery in one use, so it is best reserved for larger units.
How long does it take to recharge a portable power station?
Charge time depends on station capacity and charger wattage. Dividing capacity by charger input wattage gives a rough estimate. A 1000Wh station charged at 400W AC input takes roughly 2.5 hours. Smaller units with basic chargers may take 6 to 10 hours.
Is a portable power station safe indoors?
Yes. Unlike petrol generators, portable power stations produce no exhaust fumes and are safe to use indoors. They also operate quietly, making them suitable for bedrooms when running CPAP machines or for offices during power outages. Follow the manufacturer's temperature and storage guidelines.
Know What Your Power Station Can Do
Use this calculator to estimate runtime for your devices, then explore our battery tools to compare capacity, watt-hours, and energy storage options for camping, backup, and off-grid use.
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