@rfc6919 @kornel @jimbob Same!

Let's see … I have a cheap NiMH AAA in front of me; it lists its capacity as 900 mAh; at ~1.2 V that's pretty much 1 Wh. Spending that in 2 minutes gives 30 W. Maybe that could sustain the smallest G5 (CPU only) when it's mostly idling? AFAICT the watch in question holds ~1/3 of that.

As 2 minutes was given as a hard upper bound and seems in the right ballpark, I'd say it checks out, but there might be enough wiggle room to reduce that limit to under a minute :)