If there’s one thing obvious within all the rumors of a coming iWatch from Apple is the reality that no one wants to charge a watch every day or every other day. This would be a classic example of a device that is less convenient than what we already have. (I know that an iWatch would be miles away from what a Swatch does, but from a consumer behavior perspective, I think it’s fair to say folks don’t want to take their watch off every night and charge it. I also suspect they don’t want to worry about whether they forgot to take it off before showering.)
That leaves a couple options. Make it extraordinarily low power. That’s going to be almost impossible with a high resolution display. The Kindle has such incredible battery life because eink isn’t back lit. The other alternatives? Figure out a way for the watch to charge itself.
The leading theories (rumors) are that Apple is looking at some kind of glass with solar capabilities or even that the company is exploring charging systems that work based on movement, a design that exists in current watches. The solar argument is related to reports that Apple might be adding a solar charging layer to its sapphire glass screens. The issue is whether the current generated by such a small surface area really makes much of a difference and whether we actually use these devices in environments with sufficient access to light.
Given the job postings at Apple related to solar and battery tech, it’s not a stretch to think that Apple is also trying to answer these questions.