By Portable Power Lab | Last Updated: December 2025
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The number one mistake people make when buying a portable power station is getting the math wrong.
Marketing brochures often claim a 500Wh battery will “run a mini-fridge for 10 hours.” But they don’t tell you which mini-fridge, or what the ambient temperature is, or the inverter efficiency loss.
At Portable Power Lab, we believe in real-world data.
Below is our master database of 2025 Appliance Wattages. We have compiled average Starting (Surge) Watts and Running Watts for common household, camping, and medical devices.
Bloggers & Journalists: You are welcome to use this data for your own articles. Please credit PortablePowerLab.com as the source.
The “Golden Formula”: How to Calculate Runtime
Before you look at the charts, you need to know the formula. You cannot just divide Battery Size by Wattage. You must account for Inverter Efficiency (usually 85%).
Formula:
(Battery Capacity Wh × 0.85) ÷ Device Wattage = Hours of Runtime
- Example:
- Battery: EcoFlow Delta 2 (1024Wh)
- Device: Starlink (50 Watts)
- Math:
(1024 × 0.85) ÷ 50= 17.4 Hours
🏠 Home Backup: Kitchen & Essentials
Note: “Starting Watts” is the split-second burst of power needed to turn a motor on. Your power station’s Inverter Rating must handle this number.
| Appliance | Running Watts (Avg) | Starting Watts (Surge) | Est. Runtime on 1000Wh Battery |
| Refrigerator (Full Size) | 150W – 200W | 1200W+ | 4 – 6 Hours |
| Chest Freezer | 30W – 60W | 500W | 14 – 28 Hours |
| Coffee Maker | 1000W | 1000W | 45 Minutes (approx 8 pots) |
| Microwave (700W) | 1000W | 1500W | 45 Minutes |
| Space Heater | 1500W | 1500W | 30 Minutes (Do not recommend) |
| TV (55″ LED) | 60W – 100W | 100W | 8 – 14 Hours |
| WiFi Router | 10W – 15W | 15W | 55+ Hours |
| Sump Pump (1/2 HP) | 800W – 1050W | 2150W+ | ~45 Minutes |
Lab Note: Large appliances like Fridges and Sump Pumps cycle on and off. They don’t run 24/7. The runtimes above assume the compressor is running continuously. In reality, a fridge might only run 20 minutes per hour, effectively tripling the runtime shown above.
🚐 Camping & Van Life Gear
| Device | Running Watts (Avg) | Starting Watts | Est. Runtime on 500Wh Battery |
| 12V Fridge (Dometic/Iceco) | 35W – 50W | 60W | 8 – 12 Hours (continuous) |
| Starlink (Standard) | 50W – 75W | 100W | 5 – 8 Hours |
| Laptop (MacBook Pro) | 40W – 60W | 60W | 7 – 10 Recharges |
| Drone Charger (DJI) | 30W – 50W | 50W | 8 – 12 Recharges |
| Electric Blanket (Low) | 40W – 60W | 60W | 7 – 10 Hours |
| Smartphone | 5W – 10W | 10W | 40+ Recharges |
| Projector (Mini) | 40W – 60W | 60W | 7 – 10 Hours |
Lab Note: For 12V fridges, using the DC Cigarette Lighter Port is more efficient than the AC Outlet. You can gain 20% more battery life by avoiding the AC inverter conversion.
🏥 Medical Devices (CPAP)
Based on ResMed AirSense 10/11 averages.
| Settings | Power Draw (DC) | Power Draw (AC Plug) | Est. Runtime on 500Wh Battery |
| Humidifier OFF | 7W – 10W | 15W | 40+ Hours (4-5 Nights) |
| Humidifier Low (2-3) | 25W – 35W | 45W | 12 Hours (1.5 Nights) |
| Humidifier High (6-8) | 50W – 60W | 75W | 7 Hours (1 Night) |
🛠️ Tools & Garage (DIY)
| Tool | Running Watts | Starting Watts | Minimum Inverter Required |
| Corded Drill | 600W | 900W | 1000W Inverter |
| Circular Saw | 1400W | 2500W | 3000W Inverter (Heavy Duty) |
| Air Compressor | 1000W | 3000W+ | 3000W+ Inverter |
| Battery Charger (18V) | 50W | 50W | Any |
Which Size Generator Do You Need?
Based on the data above, here is our quick recommendation chart:
- Phone, Drone, Laptop only:
- Target: 250Wh – 500Wh
- Lab Pick: Bluetti EB3A or Jackery Explorer 300
- CPAP Camping (Weekend):
- Target: 500Wh – 700Wh
- Lab Pick: EcoFlow River 2 Pro
- Van Life (12V Fridge + Laptop):
- Target: 1000Wh+
- Lab Pick: EcoFlow Delta 2
- Home Backup (Fridge + TV):
- Target: 2000Wh+
- Lab Pick: Bluetti AC200L
Frequently Asked Questions
Q: Why is “Starting Watts” higher?
A: Appliances with electric motors (fridges, pumps, saws) need a massive jolt of electricity to get moving from a standstill. This lasts milliseconds but can trip your generator if the inverter isn’t strong enough.
Q: Does cold weather affect these numbers?
A: Yes. In freezing temperatures (below 32°F / 0°C), standard Lithium-ion batteries can lose 20-30% of their capacity. For winter use, we recommend insulating your battery.