Your phone battery degrades a little every day. Lithium-ion cells are consumable components — they’re designed to wear out. The question isn’t whether your battery will degrade, but when it’s degraded enough to warrant replacement. Here are five signs it’s time.
1. Your phone dies at 15-20% instead of 1%
This is the most reliable sign of a worn battery. A healthy lithium-ion cell delivers consistent voltage from 100% down to about 5%. A degraded cell’s voltage drops sharply under 20%, and the phone’s power management system shuts it down to protect the components. If your iPhone shuts off at 15% or your Samsung dies at 18%, it’s not a software bug — it’s a battery that can no longer sustain voltage under load.
On iPhones, check Settings > Battery > Battery Health. Below 80%, Apple officially considers the battery degraded and recommends replacement. On Samsung, dial *#0228# to access the battery status menu (varies by model). On other Android phones, apps like AccuBattery can estimate health after a few charge cycles.
2. Your phone gets uncomfortably hot
All phones warm up during fast charging or gaming. But if your phone gets hot during normal use — browsing, messaging, calls — that’s a red flag. A degraded battery has higher internal resistance, which means more energy is lost as heat during both charging and discharging. The phone’s thermal management system throttles performance to protect itself, which is why an overheating phone also feels slow.
In Malta’s climate, battery heat is a bigger problem than in cooler countries. Using a phone with a degraded battery outdoors in July (35°C+ ambient) can push internal temperatures past 45°C, at which point permanent damage accelerates. If your phone gets hot enough to be uncomfortable to hold, get the battery checked.
3. Your screen is lifting from the frame
This one’s urgent: a swollen battery is expanding and pushing the screen away from the phone frame. Lithium-ion cells swell when they fail internally — the electrolyte decomposes and produces gas that inflates the sealed battery pouch. A swollen battery is a fire risk and should be addressed immediately. Don’t press on the screen to flatten it. Don’t charge the phone. Bring it to a repair shop and have the battery safely removed and replaced.
4. Your screen-on time has dropped dramatically
Remember when your phone lasted a full day? If you’re now reaching for the charger by 2pm with the same usage patterns, your battery has lost significant capacity. A new phone might deliver 6-8 hours of screen-on time. A degraded battery might manage 3-4. That’s a 50% capacity loss that affects how you use your device every single day.
5. Your phone throttles to the point of being unusable
Apple was the first to admit it (after being caught): iPhones with degraded batteries are deliberately throttled to prevent unexpected shutdowns. Settings > Battery > Battery Health will show if ‘performance management’ has been applied. Android phones don’t throttle as aggressively, but thermal throttling — performance reduction due to heat — has the same effect. If your phone is noticeably slower than it used to be, and a factory reset doesn’t fix it, battery degradation is the likely culprit.
What next?
If you recognise two or more of these signs, it’s time for a battery replacement. At Sigma Mobiles, we replace phone batteries with genuine-capacity cells, same-day in our Hamrun workshop. The replacement takes about 30 minutes, and every battery includes a 90-day warranty.