Typical wattage range
10-35 W. Use a measured average when the device matters.
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Small electronics
Tablet charging Runtime Estimate
USB-C charging efficiency is usually better than AC inverter charging, but charger and cable limits still matter.
Planning default
20 W at 100% duty cycle, or about 20 W average load.
Confidence label
Estimated. Treat the result as a planning estimate, not a lab measurement.
1,024 Wh example
With 92% efficiency and a 10% reserve, about 848 Wh remains usable. At the default load, that is roughly 1d 18h.
Evidence behind these load values
The value class and conditions stay separate from the number. Missing source details remain unknown rather than becoming assumptions.
Device measurement guide
Use the measured average
Enter a steady watt reading or a full-cycle average in the runtime calculator. Use 100% duty cycle for an average that already includes on and off periods.
- Device wattage (W)
- Read watts after a steady load settles; record energy over time for a cycling load.
- Duty cycle (%)
- Average watts calculated from Wh divided by hours already include off-cycle time, so do not apply duty cycle again.
Use this load in the runtime calculator
Verify your watts
- Check the device label for running watts or input amps and volts.
- Use a plug-in watt meter for AC loads when the result matters.
- For cycling loads, measure long enough to capture on/off behavior.
Check output path
- AC inverter loads usually lose more energy than direct DC loads.
- Keep reserve for cold weather, battery age, and load changes.
- Do not treat label capacity as fully usable watt-hours.
How to use this scenario
- Start with 20 W if you do not have a watt-meter reading yet.
- Tablet charging is treated as a continuous load, so runtime is sensitive to the real wattage you enter.
- Keep at least a planning reserve because battery age, temperature, output path, and device settings can move the result.
Watch-outs
- The scenario wattage is an estimate. Measure the real load before relying on it for outage, travel, or critical planning.
Sources
- U.S. Department of Energy power and energy definitions (official) - Defines watts, volts, amps, and kilowatt-hours for the site's unit conversions; it is methodological context, not a source for individual appliance wattage ranges.
Use this load in the runtime calculatorCheck source wattage rangesFind a practical power station sizeCompare runtime by battery capacity
Related Scenarios
Compare nearby loads before assuming one wattage profile covers your setup.
Phone charging
5-30 W, default 15 W, confidence: Estimated.
Camera battery charger
5-30 W, default 15 W, confidence: Estimated.