Glossary
Fast charging (watts)
The peak wattage a device accepts while charging. Higher numbers mean faster top-ups, but real-world charge time depends on the curve, not just the peak.
Charging wattage is marketed as a single peak number — "120 W" or "67 W" — but that wattage is only sustained for a small window of the charge curve.
How the curve works
- 0–30%. Peak wattage. The cell tolerates high current at low state of charge.
- 30–80%. Tapers to manage heat and cell stress.
- 80–100%. Trickles slowly; the last 20% often takes as long as the first 80%.
Real-world times
- 120 W phone: 0→100% in ~20 minutes.
- 67 W phone: ~40 minutes.
- 27 W (iPhone): ~90 minutes.
Heat and longevity
Higher peak wattage means higher cell temperatures, which accelerate battery wear. Some manufacturers (OPPO, Xiaomi) use dual-cell architectures to split current and reduce per-cell stress; others (Apple, Samsung) cap wattage to favor cell longevity.
What's needed
- A compatible charger and cable supporting the device's protocol (USB-PD PPS, SuperVOOC, etc.).
- A USB-C cable rated for the wattage (5A cables for 100+ W).
Where this matters
Categories that use fast charging (watts)
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