How to Judge Battery Quality by Charging Speed?

Charging speed is an important hidden indicator for evaluating the quality of a used iPhone battery. There are significant differences in charging speeds between normal, aged, and refurbished batteries.

According to Apple’s official specifications:

For iPhone models that support fast charging (iPhone 8 and later), using an original or MFi-certified fast charger and cable, the battery can charge from 0% to approximately 50% in 30 minutes, and fully charge in about 1.5–2 hours.

For older models without fast charging, a full charge typically takes 3–4 hours.

If the charging speed of a used iPhone is noticeably abnormal, it may indicate battery quality issues:

Slow charging: If it charges less than 30% in 30 minutes, or takes more than 4 hours to fully charge (for non-fast charging models), the battery cells may be aged with increased internal resistance, reducing charging efficiency.

Irregular charging: If the speed fluctuates (e.g., 60% in the first 30 minutes but only 80% after another hour), it could be a refurbished battery with poor cell consistency, posing potential safety risks.

Note: Charging speed is also affected by chargers and cables. Always use original or certified accessories for testing to avoid misjudging battery quality due to faulty accessories. When purchasing, test the charging speed on-site and combine it with battery health percentage and cycle count for a comprehensive assessment of the battery’s true condition.