You're making an assumption that the battery would get 70% smaller. I never said that. The Apple watch is fat, and pretty much everything in it could be and will be smaller with each generation. I bet they could make the watch 2/3 thinner and still keep a battery close to the current mAH rating by shrinking everything else inside and/or reconfiguring the battery shape a la Macbook Air with the stepped battery. Add better power management with each generation and incremental battery technology updates and I don't think it's absurd that in 3-4 years you have an Apple watch that's much thinner and lasts 3 days.
Not it's not FAT. It's the average size of current watches on the market;
check it out yourself before saying nonsense.
Right.... bet.
No... Not in the way your talking.
The main obstacle to battery life, besides the battery itself is the screen tech, next is the com chips.
Nothing in the pipeline will take significant less power from them in the next 5 years: maybe 25% less.
Say, 100% less power used by the CPU (if people don't use it more obviously by using more power hungry apps).
As for the battery itself, there is no tech in the pipeline to increase the density in a commercial product significantly there too; let's be generous and give 30% more there too (though I have no clue were this would come from...)
So extra battery life by this very rosy glass scenario would be about
0.3 * (1 /(1 - ((50%+30%) * 0.25 + 1.0 * (20%)))
0.3 * (1/0.60)
= about 50% , pretty good, but not anywhere near what your talking about.
The thing that would make the most difference is a dynamic refresh screen tech that takes very little power.
If you get that, then a long battery life is possible.
Maybe people get to the second day with the 42 mm, with this, they'd get to the third day (so 3 days between charges)
BTW, the inside of the Watch is already pretty tight, not much room to cut things off...
BTW, getting it much thinner AND having a long battery life is incompatible; you'll get one or the other (or a bit of both).
Also, you forget that instead of adding battery life, many people may want more functionality instead.
Adding Cell phone function and GPS would kill any increase in battery life from any source and assure that the watch would not get thinner.
I have a Garmin. Two of them in fact. Counting these two, I've had 4 different models (301, 305, 315xt, 910xt). I would put the odds of having a GPS in the next Apple Watch at less than 50%. I just won't be buying one until they do, because it would be something I take off to go run, and what would the point of that be. To me, it's not a useful health and fitness device without a GPS.
Huh! Why on earth do you need a GPS to run? Are you lost? The accelerometer (when it's tuned to your stride) gives you the exact same info (just without were you went). Unless your running in the brush or in a place with much hills, I don't get why you'd need a GPS. The GPS has a precision of +- 6-8 meters, so your not gaining much by using it, especially in an urban setting (and it's kill your battery).