How to tell when your phone battery needs replacing
Battery wear is gradual, which is why most people put up with a failing one far longer than they need to. Here is how to tell the difference between a battery having a hard day and a battery that is finished.
The signs that actually mean something
- It shuts down with charge left. The phone dies at 20%, 15%, sometimes 40%. A worn cell cannot hold its voltage under load, so the phone cuts out to protect itself. This is the clearest sign of all.
- Charge collapses in steps. 60% to 30% in a moment, rather than draining smoothly.
- It dies fast in cold weather. A healthy battery handles cold. A worn one falls over.
- The phone has become slow. On iPhones especially, a degraded battery causes the system to throttle performance to avoid unexpected shutdowns. People replace phones for feeling slow when a battery was the problem.
- It gets hot doing very little. Warm while gaming is normal. Warm while sitting on a table is not.
- It will not hold charge overnight with nothing running.
Check the actual number
On an iPhone: Settings → Battery → Battery Health & Charging. The Maximum Capacity figure is what the battery holds now against when it was new. Below about 80% you are into replacement territory, and most people notice the difference well before that.
On Android it varies by manufacturer — some show battery health in Settings under Battery or Device Care, and Samsung phones report it through Samsung Members under diagnostics. If your phone hides it, bring it in and we will measure the cell directly, which is more reliable than any app.
Be wary of "battery health" apps from the Play Store. Most of them estimate from charging behaviour and are close to guesswork.
Swelling: deal with this today
This one is not about convenience. Stop and check for:
- A screen lifting away from the frame, often starting at one corner
- A back cover bulging, or a phone that rocks when placed flat
- Gaps opening around the edges of the display
A swelling lithium cell is generating gas internally. It will keep expanding, it can crack the display from behind, and a punctured or crushed cell is a genuine fire risk. Stop charging it, power the phone off, and bring it in today. Do not press the screen back down, do not carry it loose in a bag with keys, and do not leave it charging overnight "until the weekend".
Why batteries wear out
Lithium-ion cells have a limited number of charge cycles, and every full cycle takes a little capacity. Two things speed it up: heat, which is the main enemy — charging in a hot car or gaming while plugged in does real damage — and sitting at 100% or near 0% for long periods. If you want a battery to last, keeping it roughly between 20% and 80% and away from heat does more than any app claiming to optimise charging.
Getting it replaced
A battery replacement is one of the quicker jobs and is normally done while you wait. Price depends on the model, so message us on WhatsApp with your model and we will tell you what it costs before you come in.
One thing worth saying: if your phone shuts down early and will not charge properly and gets hot, the battery may not be the whole story — charging circuitry faults produce similar symptoms and a new battery alone will not fix them. We check the charging side before replacing a cell, so you are not paying twice.