As in the prior version, further access is barred by a tiny tri-point screw—one of 64 possible contingencies we've come prepared for.

The top third of the watch is labeled "Taptic Engine," and that's mostly true—but the label also hides a bracket that guards, among other things, the battery connector we're searching for.

Time to pick away the power pack and see what gives this watch its all-day go-juice.

Professional teardown engineer on a closed track. Do not attempt battery replacement on the go.