How to Know When Your iPhone Battery Needs Replacement

iPhones are tough, but batteries have their limits. Over time, every charge cycle takes a little life out of them — and before you know it, the phone that once lasted all day barely makes it to lunch.

Here’s how to tell when your iPhone’s battery is ready for a refresh.

You’re Charging More Than Usual

If you find yourself topping up before midday, your battery’s health is likely dropping.

Modern lithium-ion batteries lose capacity gradually, especially after about 500 charge cycles — roughly two years of daily use.

The Battery Health Reading Is Under 80%

Open Settings → Battery → Battery Health & Charging.

If it shows “Service” or the Maximum Capacity is under 80%, it’s time.

This means your battery no longer holds enough charge for a full day, even with light use.

Unexpected Shutdowns or Sudden Drops

Does your iPhone jump from 40% to 5% in a flash?

That’s a sign the internal cells are struggling to deliver stable power.

Replacing the battery will bring those readings — and your peace of mind — back to normal.

It Feels Hot — Even When Idle

Excess heat usually means your phone is working harder to compensate for battery inefficiency.

If it’s getting warm in your pocket or while charging, that’s a good cue to get it checked.

It’s Swelling or Lifting the Screen

A swollen battery is rare, but serious.

If your screen looks slightly lifted around the edges or no longer sits flush, stop using it and have it replaced immediately — pressure from inside the phone can damage the display or logic board.

When to Visit a Professional

In Christchurch, most iPhone battery replacements take around two hours or less and cost between $89 and $149, depending on the model.

At Phone Repair NZ, every replacement includes fitting, testing, and a six-month warranty covering both the part and the workmanship.