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Apple Watch Series 4 has 20% lower battery capacity than Series 3

When Apple announced the Apple Watch Series 4 it promised the same 18-hours of battery life as its predecessor. That news may have come at a disappointment to some Apple fans, seeking around the clock battery life.

However, today’s reports that the physical battery has a 20% smaller capacity than the Series 3 cell put a slightly different spin on things.

The confirmation comes from Apple’s Product Information Sheet, which was spotted by a MacRumors reader. The document points out that, despite the larger display, the battery capacity has dropped on both Series 4 devices.

The 44mm Series 4 capacity is down 16.5% on the 42mm Series 3, while the 40mm Series 4 is down 19.7% on the 38mm Series 3. Here’s how the Product Information Sheet breaks it down:

  • Apple Watch Series 3 (42mm): 1.34 watt-hours
  • Apple Watch Series 4 (44mm): 1.12 watt-hours
  • Apple Watch Series 3 (38mm): 1.07 watt-hours
  • Apple Watch Series 4 (40mm): 0.86 watt-hours

With these stats in mind, it’s actually impressive that the Apple Watch Series 4 is able to achieve the same all-day battery life, rather than a let down.

We can presume Apple has done plenty of work in watchOS 5, while the new S4 chip offers more in the way of power efficiency. However, the company has not responded to requests for comment on today’s report.

Related: Best smartwatch 2018

The Series 4 offers the first significant redesign of the Apple Watch since the original. As well as the larger display, the casing is slimmer while there’s sleeker integration of the Digital Crown and power button. This may have caused Apple to rejig the internal components, leaving less space for a battery offering the same capacity.

Elsewhere, the Apple Watch Series 4 promises brand new heart-rate sensing features that will tell users if they have a low or irregular beat. There’s also a built-in ECG, which is a first for an over-the-counter consumer device.

Have you ordered the Apple Watch Series 4 yet? Will this finally get you on board with Apple’s smartwatch companion? Drop us a line @TrustedReviews on Twitter.


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