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Interactive Sizing & Electrical Reference

The Biggest Confusion in Solar Generators

When you look at portable power stations (like Jackery, EcoFlow, or Bluetti), you'll see two similar-looking numbers on the spec sheet: Watts (W) and Watt-Hours (Wh). Confusing these two is the main reason people buy the wrong size power station.

1. Watts (W) = Speed / Output Power

Watts dictate how powerful a device the battery can run. It is the size of the internal inverter.

  • If a power station is rated for 1000 Watts, it can run a 900W coffee maker.
  • It cannot run a 1500W space heater. It will simply shut down because the output load is too high.

Think of Watts as the horsepower of a car's engine.

2. Watt-Hours (Wh) = Gas Tank / Capacity

Watt-Hours dictate how long the power station can run a device before the battery dies. It is the physical size of the internal lithium battery.

  • If a power station has a capacity of 1000 Watt-Hours (Wh), it can output 1000 watts of power for 1 hour.
  • Or, it can output 100 watts of power for 10 hours.

Think of Watt-Hours as the size of the car's gas tank.

Sizing Example: CPAP Machine

Let's say you want to run a CPAP machine while camping. The CPAP draws 50 Watts with the humidifier on, and you sleep for 8 hours a night.

Step 1: Check the Output (Watts)

Does the power station have an inverter larger than 50W? Almost every power station on the market has at least a 200W inverter, so you are perfectly fine here.

Step 2: Check the Capacity (Watt-Hours)

Energy Needed = 50 Watts × 8 Hours = 400 Watt-Hours (Wh)

You need exactly 400 Wh for one night. Because power stations are never 100% efficient (inverters lose about 15% to heat), you should multiply by 1.2 to be safe.

Target size: A power station with at least a 500 Wh battery.

Comparing Popular Sizes

Class Typical Inverter (Watts) Typical Battery (Wh) Best Used For
Small 300 W 250 Wh - 300 Wh Charging phones, laptops, running LED lights.
Medium 1000 W 700 Wh - 1000 Wh CPAP machines, small TVs, mini-fridges.
Large 2000 W 2000 Wh Full-size fridge backup, microwaves, coffee makers.
Home Backup 3600 W 3600 Wh+ Sump pumps, window AC units, heavy power tools.
Battery Chemistry Tip: Look for power stations that use LiFePO4 (Lithium Iron Phosphate) batteries rather than NMC. LiFePO4 lasts for 3,000+ charge cycles compared to 500 cycles for older lithium chemistries.

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