LTE Apple Watch Battery Tests: Will cellular destroy the Series 3 battery?

The new Series 3 Apple Watch will bring a much-requested feature when it launches on the 22nd: Cellular and LTE connectivity. That means that, yes, you'll be able to make phone calls, send messages and emails, get directions, use third-party apps, and give Siri commands.

LTE is fully-functional on your Apple Watch when your iPhone isn't present unless you specifically disable it, so pretty much anything you can do on your Apple Watch with your iPhone connected, you'll be able to do when only connected via Cellular. In fact, you'll be able to do a little bit more: The Series 3 GPS + Cellular model will even let you stream any song from Apple Music's 40,000,000 song catalog starting in October.

But with no discernible casing size change nor battery bump, how will the Series 3's battery life fare? Apple, as always, has done some preliminary pre-release tests, which we have right here.

Apple's pre-release testing

According to the company's battery tests, both Series 3 watches (GPS-only as well as GPS + Cellular) continue to average 18 hours of battery life, with specifics highlighted below:

All-day battery life is based on 18 hours with the following use: 90 time checks, 90 notifications, 45 minutes of app use, and a 30-minute workout with music playback from Apple Watch via Bluetooth, over the course of 18 hours.Apple Watch Series 3 (GPS) usage includes connection to iPhone via Bluetooth during the entire 18-hour test. Apple Watch Series 3 (GPS + Cellular) usage includes a total of 4 hours of LTE connection and 14 hours of connection to iPhone via Bluetooth over the course of 18 hours.

While Apple doesn't note which watch configuration it used for these tests (38mm or 42mm), it did peg the Cellular watch at 18 hours' with 4 hours of LTE and 14 hours of iPhone connectivity — about what the average person might use in a given day.

Specific battery tests, however, are far less forgiving. Here's how the Series 3 fared in Apple's single-task tests:

  • Talk: 3 hours connected to iPhone, 1 hour w/ Cellular
  • Audio: 10 hours w/ Bluetooth (Apple Music streaming not tested)
  • Workout: 10 hours w/ iPhone, 5 hours using just GPS, 4 hours using GPS + Cellular

Herein lies the downside of a GPS + Cellular-enabled watch: In choosing to pursue connectivity over battery life, Apple still doesn't quite have the battery numbers to make long-distance runners (like ultra-marathoners) happy if they're using GPS, let alone GPS + Cellular.

Tests we plan to run

We'll be doing extensive battery testing for our Series 3 review to try and confirm and expound on these numbers, so stay tuned. So far, our list includes:

  • Series 3 GPS + Cellular 38mm vs 42mm
  • Series 3 GPS + Cellular with Cellular disabled vs GPS-only
  • Series 3 GPS + Cellular messaging-only
  • Series 3 GPS + Cellular workouts with continuous heart rate monitoring disabled
  • Series 3 GPS + Cellular vs Series 2
  • Series 3 GPS + Cellular vs Series 1
  • Series 3 GPS + Cellular vs comparable fitness tracker

If you have battery tests you'd like us to run, drop it below and we'll work it in when we review the watches.

Serenity Caldwell

Serenity was formerly the Managing Editor at iMore, and now works for Apple. She's been talking, writing about, and tinkering with Apple products since she was old enough to double-click. In her spare time, she sketches, sings, and in her secret superhero life, plays roller derby. Follow her on Twitter @settern.