Phone battery draining fast? How to check its health and when to replace it
Fast draining doesn't always mean a worn-out battery. Often a single app or a setting is to blame. Check the battery health first, then decide.
- Replacement makes sense
- when battery health drops below approx. 80%
- Time to check
- 5 minutes
- Replacement cost
- usually 150–500 zł
If the battery is swollen (the screen or back panel sticks out, the phone rocks on the table), stop charging it and don't try to open the case. A swollen battery can catch fire.
Step by step
Check the battery health
iPhone: Settings → Battery → Battery Health & Charging. Samsung: Samsung Members app → Diagnostics → Battery status. Other Android phones: Settings → Battery or About phone. Below approx. 80% capacity, the battery is clearly worn.
See which app uses the most power
Settings → Battery shows app usage over the last 24 hours. If one app (often social media, games or navigation) eats 30–40%, limit its background activity or reinstall it.
Turn off what runs in the background for no reason
Change location access from “always” to “while using the app”, turn off background app refresh for apps you don't need, and set a shorter screen timeout. Screen brightness is the single biggest power drain.
Update the system and restart the phone
After an update, the phone spends a day or two indexing files and uses more power. That's normal. If the problem lasts longer, a restart often stops “stuck” background processes.
Check your signal
In places with weak signal, the phone keeps searching for a network and the battery melts away. If it drains mainly at work or in the basement, it's the signal rather than the battery. Turning on Wi-Fi calling helps.
Decide whether it's time to replace it
Health below 80%, the phone shutting down at 15–20% or in the cold, sudden jumps in the percentage: these are classic signs of a worn battery. A replacement gives your phone a second life for 2–3 years.
- The battery is swollen or the case has started to come apart.
- The phone gets very hot with no load.
- The phone shuts down on its own even at 40–50% charge.
How much does a repair shop charge?
| Battery replacement (Android, popular models) | 150–350 zł |
| iPhone battery replacement (independent repair shop) | 200–400 zł |
| iPhone battery replacement (authorized repair shop) | 350–580 zł |
| Diagnosis at a repair shop | 0–50 zł |
Typical prices at independent repair shops in Poland, October 2026. Authorised service centres and big cities can be more expensive.
Repair or buy new?
A battery replacement is the best-value phone repair. It costs a fraction of the price of a new phone, and the device works like it used to. It's usually not worth it only for very old phones that no longer get security updates.
Check if replacing the battery in your phone is worth it
Pick your model and fault. In 2 minutes we show the repair cost, what the device is worth and an honest verdict.
Open the calculator →FAQ
Does charging overnight damage the battery?
Modern phones have built-in protection and slow down charging at 80–100%. Turn on optimized charging or battery protection in the settings. It really does extend the battery's life.
Does battery calibration help?
Draining the battery to zero and charging it to full can improve the percentage readout, but it won't bring back lost capacity. It fixes the indicator, not the battery.
Will anything stop working if I replace the battery outside Apple's service?
The phone will work normally, but an iPhone may show a message about an unknown part. It doesn't affect how the phone works, but it can sometimes lower the resale price.