Used iPhone shows 100% battery health despite 1000+ cycles

The 100% battery health indicator in iOS is based on how much capacity the battery retains relative to when it was new, not necessarily how many cycles it has gone through. A battery's cycle count indicates how many times it’s been charged from 0% to 100%.

If you’ve got an iPhone with 1000 cycles showing 100% health, that’s unusual. Typically, after a battery goes through several hundred cycles, it starts to show wear, and the battery health should decrease. So, it’s possible that the battery was either replaced with a new or refurbished one, or maybe the iOS was altered to make it look like it’s at 100% health when it’s not.

As for the "Unknown Part" alert, iPhones will usually display that message if a non-Apple battery is installed, but it doesn’t always trigger if the battery is an Apple-certified replacement, or if the iOS has been modified. If the battery isn’t showing any signs of wear, and the health report is still 100%, I would recommend using a third-party app like CoconutBattery (for Mac) or other diagnostic tools to check the real condition of the battery and its cycle count. You could also have Apple check the phone’s battery to confirm if it’s original or a replacement.

In short, it’s worth investigating further, especially if you’re seeing signs of performance issues or battery drain.

EddyJosue wrote:

The strange thing is that the battery yesterday dropped to 99 in the maximum capacity, The strange thing is that no ad of * Unknown piece * I investigated thoroughly and I was left with the fact that they probably altered the original Apple battery so that it was 100% with external machines, And if the iOS had been altered how would you know? I have my iPhone updated to the latest version

It is simply an aftermarket battery where the BMS(Battery Management System) was removed from the original battery and soldered onto the new one. Techs have done this to bypass the unauthorized message with some success. I suspect the Battery Health indication is correct, but you may not have the same performance or battery life of an original battery. There is also the possibility that Apple will refuse service if you were to try and replace that battery.

If the pentalobe screws are in good shape, the tech will never know it’s been opened.

The battery was re-flashed to show 100% battery health. It’s a lot of labor, but in markets with low cost labor, it’s cheaper than replacing a battery. Unfortunately, the customer doesn’t get what they think they’re paying for.

Find someone with a Mac and install Coconut Battery. It will give the manufacturing date of the battery. It should be before the manufacturing date of the iphone, also shown there. If not, it is a replacement, by whom, difficult to tell.

Parts and service history

With iOS 15.2 and later and iPhone XR, iPhone XS models, and later—including iPhone SE (2nd and 3rd generation)—you can go to Settings > General > About for the parts and service history of your iPhone. You can also find out if the battery has been replaced. If the replacement was done using genuine Apple parts and processes, "Genuine Apple Part" will appear next to Battery.

If you want to replace with a genuine Apple battery, you will need to make an appointment at the Genius Bar or take the phone to an authorized Apple service shop.

Whether they will agree to perform the service is an open question. You won't know until you try.

You can find a list of authorized Apple service shops in your area using this link:

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I doubt very much that Apple will repair any device which has already been opened by a third party.

So do I, but we can't speak officially for Apple and it cannot hurt to ask.

I have an iPhone 6 and it has 100% battery life