Most people look at one number: the percentage under Battery Health. That number is useful, but it is not the whole story, and it is not a limit Apple has set for when the battery must be replaced.
Where to find the number
Go to Settings, Battery, Battery Health & Charging. You will see two things:
- Maximum Capacity: how much charge the battery can hold now, compared with when it was new.
- Peak Performance Capability: whether the phone can draw full power when it needs to.
What Apple actually says about 80 percent
This is a common misunderstanding, including on repair sites. Apple states that:
- Batteries in iPhone 14 and earlier are designed to retain 80 percent of their original capacity at 500 complete charge cycles under ideal conditions.
- Batteries in iPhone 15 and later are designed to retain 80 percent at 1000 complete charge cycles.
So 80 percent is a design expectation over the battery’s lifetime, and the threshold Apple itself uses to replace the battery for free under AppleCare. It is not a rule that the phone has to go in for repair the moment it hits 79 percent.
We point this out because it is often presented as a hard limit. It is not, and you should not replace a battery you are still happy with.
The “Service” message
If your iPhone instead shows a message that the battery’s health has significantly degraded, iOS has measured a real decline. Apple’s own wording is that the battery can be replaced to restore full performance and capacity. That message is a more precise signal than the percentage alone.
The signs that actually matter
Whatever the percentage says, these are the real reasons to replace a battery:
- It shuts down suddenly at 20 or 30 percent. A classic sign that the battery cannot deliver power under load.
- It no longer lasts the day with the same use as before.
- It has become slow after an update. iOS throttles performance to avoid unexpected shutdowns when the battery is worn. A new battery removes that limit.
- It gets hot during completely normal use.
- The back glass or the screen is bulging. Stop using it, and have it checked straight away.
One of these is enough. If the answer is no to all of them and the phone otherwise does what it should, wait.
What it costs
The price depends on the model, and you see it in our price calculator as soon as you pick your iPhone. It includes VAT, travel and the part. We come to you anywhere in Copenhagen, and a battery replacement typically takes under an hour.
What you can do yourself to preserve the battery
- Turn on Optimized Battery Charging. It holds off on the last few percent until you need the phone.
- Avoid leaving the phone in a hot car or in direct sun. Heat wears the battery more than charging does.
- You do not need to charge to 100 every time, and you do not need to run it all the way down. Both are myths from older battery types.