There was one sensor that wasn't fully optimized, working on it could've added maybe 4 or so hours to the battery life (up to 8 if all the best case most optimistic estimates came through), but other than that OS architecture of the Band ensured optimal battery life.
Having that many sensors, and a screen that bright, on a device that small, just sucks up battery.
For what it is worth (nothing!), if the majority of health sensors were turned off, and the Band was only used as for productivity, the battery could easily last over 3 days. That is if memory serves me correct. :) (I'm wearing one right now, but I'm too lazy to turn everything off and come back in a few days to comment!)
Some Cambridge folks figured out how to convert ATP into (extremely small amounts of) electricity [1].
If you had a route from extracting lipids in the bloodstream, to feeding it to mitochondria in some kind of controlled culture, carry away the carbon dioxide, heat and water, then extract and feed the ATP to the aforementioned Cambridge process, then you might be able to power your wearable tech from your bad eating habits. That 5,000 calorie chocolate volcano cheesecake death-on-a-dish now gets a "hh:mm" advertised next to it. Militaries around the world will then be faced with adding more calories to their already-calorie-loaded rations. Corn farmers in the US will rejoice.
Thank goodness that route I described is not anywhere near feasibility in the next several decades. I'm dubious our ecosystem could sustain that kind of demand for more food calories.
Sorry, I wasn't clear. I meant it more as a personal preference. Considering the sensors and screen, a 2 day battery life was pretty great and certainly one of the reasons it was (and still is) better than the Apple Watch and G3, IMO.
I just meant I value a longer battery life pretty highly. So, something like a MS Band "lite" with a less feature rich sensor package, a 2 tone oled display, and 6 to 7 day battery life would have hit that sweet spot for me, personally.
I really like being able to wear the Charge 3 around the clock for a full week (I typically charge it during my lazy Sunday morning routine) without really worrying about it.
Have you looked at the Garmin fitness bands? The first gen was something like you describe but could go for a year on a couple of coin cells. They probably have more/better ones now, that was several years ago.
This is the reason I still use a Pebble 2 smart watch, so I need to charge it once per week. For me the device is for displaying glucose values, so needing to charge it every day is not really an option.
Battery life was provably as good as it could be!
There was one sensor that wasn't fully optimized, working on it could've added maybe 4 or so hours to the battery life (up to 8 if all the best case most optimistic estimates came through), but other than that OS architecture of the Band ensured optimal battery life.
Having that many sensors, and a screen that bright, on a device that small, just sucks up battery.
For what it is worth (nothing!), if the majority of health sensors were turned off, and the Band was only used as for productivity, the battery could easily last over 3 days. That is if memory serves me correct. :) (I'm wearing one right now, but I'm too lazy to turn everything off and come back in a few days to comment!)