While the iPhone's battery continues to shrink in capacity, Apple's watch battery has been subtly pumped up:

The Series 3 battery, designated A1848, packs in 1.07 Whr (279 mAh at 3.82 V).

That's nearly a 4% increase from the 1.03 Whr battery we found in the Series 2—which itself was a whopping 32% increase over the original Apple Watch's 0.78 Whr cell.

We're curious to see how Apple managed to beef up the battery while still leaving room for the added functionality of cellular antennas, radios, power amplifiers, SIM card, and so on—all in the same form factor as before.