Symptoms
- Phone doesn't last as long as it used to on a full charge
- Battery care app shows reduced capacity or a maintenance recommendation
- Battery drains fast even with light use
- Phone feels noticeably slower when battery is low
Likely causes
- CommonNormal aging from charge cyclesLithium-ion batteries lose capacity gradually, typically reaching around 80% after 500 full charge cycles.
- CommonFrequent full discharges or extreme heat exposureLetting the battery hit 0% often or leaving the phone in hot cars accelerates wear.
- PossibleKeeping the phone plugged in at 100% for long periodsConstant full-charge states stress the battery over time, though many phones now offer optimized charging to offset this.
- Less commonA single defective battery cellOccasionally a battery degrades unusually fast compared to its charge cycle count.
What to do
- Check for a battery health or battery care feature in Settings > Battery, or your manufacturer's dedicated app, if available.
- Compare how the phone performs now to a few months ago at similar charge percentages.
- Turn on any adaptive or optimized charging feature if offered, to reduce time spent at 100%.
- Avoid leaving the phone in direct sun, hot cars, or under a pillow while charging.
- Try to keep the battery generally between 20% and 80% for daily use when convenient.
- If capacity has clearly dropped and it's affecting daily use, that's a normal point to consider a replacement.
- Back up the phone before any battery service in case it requires a restart or reset.
- Ask a repair shop to check exact battery health if your phone doesn't show it natively.
When to call a pro
Once battery capacity has clearly dropped and daily use suffers, a manufacturer service center or repair shop can replace the battery to restore full-day performance.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.