5 signs your smartphone battery needs replacing

Every lithium-ion battery has a set life cycle. After roughly 500-800 full charge cycles — about two to three years of average use — its capacity starts to drop noticeably. This is not a defect: it is the chemistry of Li-Ion cells. Apple itself states that after 500 cycles an iPhone battery retains around 80% of its original capacity.

The problem is that many people do not realise the drop in their phone's performance is down to the battery rather than the device itself. They carry on with a phone that runs flat in a few hours, shuts down without warning or crawls along, when an inexpensive battery replacement would give it a new lease of life.

If your phone used to reach the evening on 30% and is now dead by mid-afternoon, the battery is losing capacity. You can check its health in the settings: on iPhone go to Settings > Battery > Battery Health, where you will find the maximum capacity as a percentage. On Android, apps such as AccuBattery measure remaining capacity against the original.

Once capacity falls below 75-80%, the difference in running time becomes obvious. An iPhone that gave 10 hours of screen time when new gives about 7-8 at 80%, and 5-6 at 70%. At that point replacement is strongly advised. In our Leonforte workshop we replace iPhone batteries in around 30 minutes using certified parts.

Does the phone show 20% and then switch off without warning? That is one of the clearest signs of a worn battery. It happens because the battery can no longer deliver the power the processor demands at peak load — opening a heavy app, the camera, a game. The system protects itself by shutting down.

On iPhone, Apple introduced performance management precisely to avoid these sudden shutdowns: when the battery is degraded, the system slows the processor to reduce demand. That prevents the shutdown but makes the phone slower. If you notice unexplained slowdowns together with the occasional shutdown, the battery almost certainly needs replacing.

A little warmth while charging is normal, but if the phone becomes too hot to hold comfortably — especially at the back, where the battery sits — that can point to a problem. A degraded battery has higher internal resistance, which generates excess heat both charging and discharging.

Chronic overheating speeds up the degradation further, and the cycle feeds itself. If the phone is constantly warm even in normal use — not just with games or heavy apps — have the battery checked. Unusual heat is also a safety signal worth taking seriously.

This is the most serious sign and it needs attention straight away. If the screen is lifting slightly from the frame, the back panel is bowing, or the phone no longer sits flat on a table and rocks, the battery may have swollen. It is caused by gas building up inside the cell.

A swollen battery is potentially dangerous and must be replaced as soon as possible. Do not try to pierce or remove it yourself: take the phone to a qualified repair centre. At Techno Easy we handle these cases with the proper safety procedures and certified disposal of the spent cell. If you suspect swelling, come to our workshop in Leonforte or Catenanuova right away.

If the phone takes far longer than usual to charge, or the percentage seems to climb and then fall while it is plugged in, the battery is showing its age. Before blaming the battery, check that the cable and charger work by trying them with another device, and clear any dust out of the charging port.

If the problem persists with a working cable and charger, the battery can no longer hold charge efficiently. At that point replacement is the only answer. At Techno Easy battery replacement starts at €35 for the most common Android models and €55 for iPhone, with quality parts and a 6-month warranty on the battery fitted.