We will quickly run the numbers and I can get back to you about expected battery life.
In the meantime, can you explain more about your intentions? Are you actually planning to swim continuously in a pool for 8 hours??? I'm a bit concerned about the size of the .fit file that would be generated and whether we might fill up memory or something. I'll have to check with the engineers on that, if that is your plan. Or, is this a use case where multiple swimmers will be using the watch each for shorter sessions over the course of a day?
We quickly ran the numbers assuming 56 hours per week of usage for swimming and we end up with 3 months of battery life. Of course there are assumptions in our models about time in sleep mode, backlight presses, etc. so individual battery life will vary.
