Glossary
Watt-hour (Wh)
A unit of energy capacity. A 100 Wh battery delivers 100 watts for one hour, 50 watts for two, etc. The canonical spec for laptop and power-station batteries; airlines cap carry-on at 100 Wh.
Watt-hours measure total energy. Wh = (mAh × V) / 1000. A 5,000 mAh / 7.6 V phone battery is 38 Wh.
Practical reference points
- Smartphone — 14–22 Wh.
- Tablet — 30–45 Wh.
- Ultrabook — 50–80 Wh.
- Gaming laptop — 90–99.9 Wh (limited to stay under FAA carry-on cap).
- Power station — 250–4000+ Wh.
Why Wh beats mAh for cross-device comparison
mAh only makes sense at a known voltage. A 10,000 mAh phone power bank at 3.7 V (37 Wh) is half the energy of a 10,000 mAh laptop battery at 7.4 V (74 Wh). For honest cross-product comparison, always convert to Wh.
Where this matters
Categories that use watt-hour (wh)
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