The Apple Watch 10 is thinner and lighter – but the battery is bigger

There is one constant in this changing world: the battery life of an Apple Watch, except Ultra, is 18 hours in normal mode and 36 hours in power saving mode. In fact, however, the manufacturer is experimenting with the batteries in the watches, and the information on the stored energy changes every year.

Apple has improved the batteries in the Apple Watch almost every year. The first Apple Watch had a battery with 0.93 watt hours in the small version, and the Series 9 already had 1.091 watt hours. We didn't think it was possible, but the battery in the Series 10 has grown again.

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The difference is particularly large in the 46 mm version, where the battery holds around six percent more energy than its predecessor, 1.266 instead of 1.19 watt hours. In the 42 mm version, the increase is smaller, with the battery becoming 2.5 percent larger: from 1.091 watt hours in the Series 9 to 1.18 watt hours in the Series 10. This is according to documents from the US authority Chemtrec.

How does Apple do this?

This, even quite small, increase in battery power is all the more astonishing when you consider that the Apple Watch Series 10 has become thinner and lighter compared to the Series 9. The casing of both versions has grown by one millimeter on the long side, but has also become one millimeter thinner at the same time. Depending on the casing material and the size, the Series 10 has become five to twenty percent lighter, while the new battery retains its weight of five grams. Apple probably achieved the most hopes by switching from ceramic to metal on the bottom.

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If you compare the Series 10 with the first Apple Watch, the battery performance has increased by 27 percent in ten generations, but why hasn't the battery life increased? This is probably because each subsequent Apple Watch has more tasks on the surface and in the background than its predecessor. The Apple Watch Series 10, for example, monitors sleep behavior and determines whether or not you have sleep apnea.