7 Signs Your Phone Battery Needs Replacing
The warning signs of a failing phone battery — from rapid drain to sudden shutdowns and swelling — and what to do about each one.
Every phone battery degrades over time — it's simple lithium-ion chemistry, not a fault. But knowing the warning signs means you can replace it before it becomes a real problem, rather than after your phone has already started letting you down.
1. Your battery drains much faster than it used to
If you're charging significantly more often than you used to, for the same kind of usage, that's the clearest sign of a degrading battery. This is different from a temporary drain caused by a rogue app — if it's been gradual and consistent over months, it's almost always the battery itself.
2. Your phone shuts off before it reaches 0%
A phone that suddenly powers off at 20%, 30%, or even higher, and then shows a different percentage (or 0%) when you turn it back on, is a classic sign the battery can no longer deliver consistent power under load.
3. Unexpected restarts or shutdowns
Random restarts, especially during demanding tasks like the camera or a game, often point to a battery that can't supply enough current, causing the phone to protect itself by shutting down.
4. The battery percentage jumps around
Jumping from 40% to 15% in a matter of minutes — with no heavy use in between — usually means the battery's ability to hold and report an accurate charge has deteriorated.
5. Your phone runs hot during normal use or charging
Some warmth during charging or heavy use is normal. A phone that consistently runs hot during light, everyday use is worth having checked.
6. Battery health tools show reduced capacity
On iPhone, check Settings → Battery → Battery Health & Charging — this shows your battery's maximum capacity as a percentage of when it was new. Once this drops meaningfully, you'll usually notice some of the symptoms above. Android battery diagnostics vary by manufacturer, but most phones have an equivalent screen under battery settings.
7. Visible swelling
If the back of your phone looks like it's lifting, bulging, or the screen appears to be pushing outward, stop using the device immediately and have it looked at. A swollen battery is a genuine safety issue, not just a performance one.
Should you replace it yourself?
Phone batteries need to be removed and disposed of carefully, and getting the reassembly wrong can damage waterproofing seals or other components. Professional replacement — with the old battery disposed of safely and the repair backed by a warranty — is almost always the better choice over a DIY kit, particularly for anything showing signs of swelling.
We replace batteries in iPhones, Samsung phones, tablets and smartwatches, all backed by our 12-month warranty. If you're not sure whether your battery is the problem, bring it in for a free diagnosis and we'll tell you honestly what's going on.