Does Fast Charging Damage an Apple Watch

There’s a widespread belief that fast charging can damage or shorten the lifespan of a lithium battery. While this could be true in certain situations it doesn’t necessarily mean that fast charging will damage your Apple Watch.

Why People Don’t Like Fast Charging

The main reason people believe that fast charging is damaging to a battery is due to the heat it generates. Extreme heat will shorten the lifespan of any lithium battery. But it doesn’t seem that the heat difference between regular charging and fast charging is that extreme.

If you’re constantly plugging in a device to charge and that device is charging to 100% every time you plugin, you will be shortening the lifespan of the battery. But with an Apple Watch, that doesn’t actually happen.

Does Fast Charging damage the battery?

I haven’t noticed any difference in battery life compared to older models which didn’t have fast charging. And looking at reports from other people it doesn’t appear that there is any widespread evidence that fast charging might be damaging the battery compared to regular charging.

The reality is that Apple has always been pretty good with managing how devices charge and they wouldn’t ship a product knowing it would cause a major customer issue.

Apple Watch Optimised Charging

Apple introduced a feature called Optimised Charging in Watch OS7. This limits the the charge to a max of 80% if the Apple Watch thinks it will remain on a charger for an extended period of time. The watch does this by learning your habits over time. So if you place your Apple Watch on the charger before you go to bed, it actually won’t charge to 100% until closer in the morning. This ensures the battery isn’t in a state of stress for an extended period of time.

Apple also does a bunch of other optimisations under the hood that are designed to extend the life of the battery.

Is it ok to fast charge an Apple Watch?

Yes. Just make sure you have optimised charging on. This will help extend the life of your Apple Watch battery.

If you’re really concerned about fast charging, just pick up a regular Apple Watch charger that charges at around 5w.

Apple does show you what the estimated max capacity of the battery is at. However, I’ve never found this to be super accurate. And due to the way Apple throttles the CPU when your battery degrades over time, for many people it will feel no different, even with a reduced capacity.