Is 90% battery health considered good for my smartphone?

Battery health is measured as a percentage of the original capacity, indicating how much charge a battery can hold compared to when it was new.

For example, if a battery originally had a capacity of 3000 mAh and now can hold 2700 mAh, its health would be reported as 90%

A battery health of 90% is generally considered good, especially for smartphones, as it indicates the device can still provide a significant amount of usable energy and performance over its lifespan

Lithium-ion batteries, commonly used in smartphones, follow a nonlinear decay pattern, meaning battery deterioration does not happen at a constant rate.

This reveals that factors like usage patterns and charging habits can significantly influence battery health

A smartphone battery can maintain a health score above 90% for several years if the device is used and charged carefully, highlighting the importance of charging habits in longevity

It is commonly recommended to keep battery levels between 20% and 80% for optimal battery health, as frequent full discharges and overcharging can accelerate battery decay

Battery health metrics can be imprecise, with the potential for up to a 10% margin of error in reporting health percentages.

Thus, a reported 90% might not indicate that it has exactly 90% of its original capacity

A battery's "State of Health" (SoH) is a key indicator, measuring the current condition relative to the battery's capacity when new.

For devices nearing 80% SoH, users should consider preparing for a replacement

The performance of a battery is also influenced by its discharge rate: heavy usage can lead to increased wear and a more significant drop in health over time compared to lighter usages

Users who frequently rely on power-intensive applications or services might see a more rapid decline in battery health compared to those who utilize their devices more conservatively

Ambient temperature plays a major role in battery health.

Future materials like solid-state batteries promise longer lifespans and faster charging times, potentially redefining what constitutes good battery health

Charging habits not only affect health but can also influence efficiency.

Fast charging, while convenient, can generate heat, which accelerates battery wear if done frequently

Battery calibration methods—like completely discharging the battery and then fully charging it—are often recommended to help recalibrate the device's battery health reporting, though their actual need is debated

In addition to capacity, factors like internal resistance and maximum current draw also contribute to what can be considered the overall "health" of a battery, which may not directly correlate with available capacity alone

Observations from various user communities suggest that mindful charging strategies and lifestyle adjustments can lead to drastically different battery performance results across seemingly identical devices