This will happen quite often, at least for the majority of the battery’s useful existence. Go through the battery threads on this forum and look at all of the coconutBattery screenshots, see how the values decrease and increase what could be described as “wildly” and seemingly impossibly. Well, that’s because there are a lot of very dynamic variables in batteries.
Battery degradation is a complex nonlinear problem, and it is crucial to accurately predict the cycle life of lithium-ion batteries to optimize the usage of battery systems. However, diverse chemistries, designs, and degradation mechanisms, as well as dynamic cycle conditions, have remained...
www.mdpi.com
Look at an analytics log, such as the partial one I included in post
#168. And even with monitoring and considering those vast number of factors, it’s impossible to perfectly measure a battery’s state of charge. So, you can probably understand why predicting an unusable state or failure is going to be nowhere near consistent/accurate — well, this applies to a lot or most technology but anyway. Speaking of accuracies… coconutBattery is a useful troubleshooting tool, at times, but it’s only fetching data for that moment — which, as was just noted, varies frequently. While still a guesstimate, the iOS/iPadOS/macOS/etc battery health calculations are still going to be reference because they account for a past data as well.
Last but not least another reminder:
My iPad 6th generation graph:
I didn’t routinely log with coconutBattery until December 2020, and primarily only do so with point OS releases.
