How to Tell If Your iPhone Battery Is Bad: 5 Warning Signs
- KiR
- Aug 29
- 2 min read
If your iPhone is acting strangely or dying way too fast, you might be wondering how to tell if your iPhone battery is bad.
Batteries degrade over time — and while they don’t fail overnight, there are warning signs to look out for.
Here’s what to check.
1. Your iPhone battery doesn’t last the day
If you’re charging your phone multiple times a day — even with moderate use — your battery health may be dropping below what’s reliable.
Dimming the screen or switching on Low Power Mode might help for a while, but it’s usually just delaying the inevitable.
2. Your phone shuts down unexpectedly
If your iPhone is turning off at 20%, 30%, or even 50% charge — that’s a common sign of battery degradation. It means the battery can no longer deliver enough power to keep the phone running reliably.
3. It feels slower and less responsive
Apple has admitted that iPhones with ageing batteries may automatically slow down to prevent crashes. If everything feels laggy, your battery might be the reason — not the processor.
4. The battery health shows ‘Service’
Go to Settings > Battery > Battery Health & Charging. If it says:
“Service recommended”
Battery capacity below 80%
…it’s time to consider a replacement. Anything under 80% usually leads to poor performance and shorter lifespan.
5. Your iPhone feels warm — even when idle
Heat is a warning sign. If your phone gets warm in your pocket, or while doing something simple like browsing or texting, the battery might be overworking or failing.
What to do if your iPhone battery is bad
If you’re seeing one or more of these signs, it’s a good idea to have your battery assessed. At Kent iPhone Repair, we:
Replace iPhone batteries quickly (usually in 30 mins or less)
Use high-quality parts
Come to your location (home or work)
Charge only if we can fix it
Serving all of Kent
We’re a mobile service, covering:
And surrounding areas
Check out our battery replacement service or get in touch for friendly advice and a no-obligation quote.
No fix, no fee. Fast battery replacement wherever you are.