Phone batteries degrade over time. After 18 months to 2 years of daily use, most batteries are holding significantly less charge than when the phone was new. The problem is that this happens gradually, so many people don't realise how much their battery has declined until it becomes a real problem.
The good news is that a battery replacement is one of the most affordable repairs available, and it can make an older phone feel like new again. Here are the five most common signs that your battery needs replacing.
1. Your Phone Doesn't Last the Day Anymore
If you remember your phone comfortably lasting all day and now you're reaching for the charger by mid-afternoon, your battery capacity has likely dropped significantly. This is the most obvious and common sign of battery wear.
On iPhones, you can check this directly. Go to Settings → Battery → Battery Health. If the percentage shown is below 80%, Apple themselves recommend a replacement. On Android, third-party apps like AccuBattery can show you a similar reading.
2. The Phone Shuts Off Unexpectedly
Does your phone suddenly turn off even when the battery indicator shows 20%, 30% or more charge? This is a classic sign of a degraded battery. As cells wear down they become unable to deliver power consistently, causing the phone to shut off without warning even when it appears to have charge remaining.
This isn't just annoying. It can also mean you lose work or miss important calls at a critical moment.
3. The Phone Gets Unusually Hot
All phones generate some warmth during heavy use, but if your phone is getting hot during basic tasks like browsing or calls, or even when it's just sitting idle on charge, that heat is often coming from the battery working harder than it should to compensate for worn cells.
Excessive heat can also accelerate the wear on other components over time, so it's worth addressing sooner rather than later.
4. The Battery Is Swollen
This is the most urgent sign. A swollen battery occurs when the cells inside have degraded and begin to expand. You may notice the back of your phone has started to lift away from the body, or the screen appears to be pushing outward.
If you suspect your battery is swollen, do not ignore it. A swollen battery can in rare cases be a fire risk. Bring the device in as soon as possible and avoid charging it overnight.
5. The Phone Is Slow or Lags on Simple Tasks
Both Apple and some Android manufacturers have introduced performance management systems that automatically reduce processor speed when the battery is too degraded to deliver consistent power peaks. This prevents unexpected shutdowns but comes at the cost of noticeable slowdown.
If your phone has become sluggish and you've ruled out software issues, a worn battery is often the cause. Replacing the battery will in many cases restore the phone to full speed.
How Much Does a Battery Replacement Cost?
Battery replacements are one of the most affordable phone repairs. At Tech Fix and Trade in Ruislip, most battery replacements cost between £35 and £75 depending on the model, and most are completed while you wait.
Compare that to a new handset costing £500 to £1,000. If your phone is otherwise working well, a battery replacement is almost always worth it.
Book a Battery Replacement in Ruislip
We carry stock for batteries on most popular iPhone and Samsung models. Walk in to our shop at 68 High Street, Ruislip, HA4 7AA or call 07919 188935 for an instant quote. We'll check the battery health on the spot and give you an honest assessment of whether a replacement is worth it for your device.