iPhone Battery Health: When to Replace It
2026-07-16 · Phone Repairs Newcastle
Your iPhone used to last all day, and now it is begging for a charger by mid-afternoon. Before you spend a thousand dollars on a new phone, check your battery health. A tired battery is one of the cheapest and quickest things to fix, and it can make an older iPhone feel brand new.
Where to find your battery health
Go to Settings, then Battery, then Battery Health & Charging. You will see a Maximum Capacity percentage. This is how much charge your battery holds now compared with when it was new. A brand-new battery reads 100 per cent, and that number slowly falls with every charge cycle.
What the percentage really means
| Maximum capacity | What to expect |
|---|---|
| 90–100% | Healthy. No action needed. |
| 80–89% | Normal ageing. Keep an eye on it. |
| Below 80% | Noticeable drop in runtime. Replacement recommended. |
| Below 70% | Short runtime and possible shutdowns. Replace soon. |
Apple considers a battery consumed once it drops below 80 per cent of original capacity. At that point iOS may also throttle peak performance to prevent unexpected shutdowns, which is why an old phone can feel sluggish as well as short-lived.
Signs it is time for a new battery
- The phone dies before the end of the day despite light use.
- It shuts down suddenly, often in the cold, even with charge remaining.
- The battery drains in big jumps, for example 40 per cent to 15 per cent in minutes.
- The phone feels warm or the back has started to bulge, which needs urgent attention.
A bulging battery is a safety issue. Stop charging and bring the phone in straight away.
Battery replacement vs new phone
A battery replacement typically costs A$79 to A$179 depending on the model, and takes well under an hour. Compare that with A$1,000 or more for a new flagship. If your iPhone is otherwise working well, a fresh battery is by far the smarter spend. It restores full runtime and removes the performance throttling tied to a worn battery.
How to make a battery last longer
- Avoid leaving the phone in a hot car. Heat is the biggest killer of lithium batteries.
- Enable Optimised Battery Charging so the phone learns your routine and slows overnight top-ups.
- Keep the phone roughly between 20 and 80 per cent where practical for daily use.
- Use a quality charger and cable rather than the cheapest option you can find.
Get your battery checked
Not sure whether your battery or something else is to blame? We can test it for you. Call our Cardiff shop on (02) 4072 2285 or drop in for a same-day battery replacement. See all our services on the homepage, and check model detail on our iPhone 13 repair page. We serve Newcastle, Cardiff, Charlestown, Kotara and the wider Hunter.
Frequently Asked Questions
At what battery health should I replace my iPhone battery?
Once maximum capacity drops below 80 per cent you will notice shorter runtime and possible performance throttling, so replacement is worth considering. Below 70 per cent it is strongly recommended.
How long does an iPhone battery replacement take?
Usually under an hour when the battery is in stock, so it is an easy same-day job.
Is it worth replacing the battery instead of buying a new phone?
Yes, if the phone is otherwise working well. A battery costs a fraction of a new handset and restores full runtime and performance.
My phone battery is swelling. What should I do?
Stop charging and using it, and bring it in promptly. A swollen battery is a safety risk and should be replaced by a professional.
Related guides
- Galaxy S26 Ultra Screen Repair: What to Know
- Cracked iPhone Screen? What to Do First
- iPhone 17 Screen Replacement Cost in Australia (2026)