Why is my iPad's battery health decreasing from 98% to 97% after charging?

Rechargeable batteries are a consumable item that will slowly decline over time - every recharge reducing the total battery capacity by a tiny amount. This effect is cumulative; eventually, the battery will need to be replaced.

With 97% Battery Health, your iPad battery is still in very good condition.

In more detail...

"Battery health" is influenced by many factors.

An iPad battery is nominally rated to retain 80% of its original capacity (when new) after 1000 full recharge cycles. Any combination of charging that together sums to 100% equates to one full charge cycle (e.g., 50% + 20% + 20% + 10% = 100% = 1 full charge cycle).

An iPad's battery is rated to retain at least 80% of its original capacity after 1000 full charge cycles - one full cycle being any combination of charging that together sums to 100% (e.g. 50 + 25 + 15 + 10 = 100 = 1 cycle). Simple arithmetic would therefore suggest that battery health will decline at about 1% for each 50 charge cycles - but this alone does not take into account that the rate of decline is non-linear.

Other factors can influence overall battery health. High ambient temperatures can permanently reduce the battery's ability to retain full charge - as can maintaining the battery at 100% charge for very long periods of time that leads to chemical aging of the battery. Limiting the battery charge to ~80% of maximum is intended to reduce the chemical aging effect. That said, independent studies have demonstrated that restricting charging to only 80% of maximum has little if any impact upon the overall longevity of the iPad's battery.

Information about iPad’s battery management can be found here:

About iPad and iPhone Charge Management Feature – Apple Support

For reassurance, if you have any concerns for your iPad or its Battery Health, you would be well advised to seek assistance directly from Apple Support - and request a remote diagnostic test of your iPad. You can contact the Support Team using the Support link at top-right or bottom-left of this page.

Alternatively, you can initiate and manage your support cases from Apple devices using the excellent Apple Support App. If not already installed, the App can be downloaded from the App Store:

https://apps.apple.com/app/apple-support/id1130498044

You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to hands-on test and assess your iPad.

Genius Bar Reservation and Apple Support Options - Apple

Please remember these are mass produced devices which have not been individually calibrated. The difference between 98% or 97% is not significant, and most likely to be a decimal rounding issue or random variation in measurement. For example, was the device at exactly the same state of charge, and same battery temperature for each measurement?

The battery health estimates are most useful if you look at the trend over a period of time. Don't worry about short term variations, think in terms of expecting hundreds of recharge cycles before you can make a useful judgement.

Two problems exist with obsessing over battery "Health":

— it is inexact

— it is non-linear

iPadOS reports health to only ±1 percent. That could mean for your observed values, one day it was 98.0% and the next it was 97.9%. That is NOT a problem because Health is inexact and not based on the actual capacity of your iPad but rather an average manufacturing initial capacity value. All mass-produced items have manufacturing tolerances.

We've had battery-powered Apple devices since 2008 and none have shown a linear decrease in "health" value.

There is not enough reliability in health to warrant it messing with your mind.