"Lux hours" doesn't mean anything

Here is a page about the fenix 7s pro solar : 

https://runningwithrock.com/fenix-solar-charging-lux-hours/ 

…“According to Garmin, these battery life specs are based on the assumption that you wear your watch all day, that it is exposed to full sunlight, and that you reach a total of 150,000 lux hours per day.“..

Good read. But it also supports my point in essence. Just 1 example:

"For example, in the default smartwatch mode – when you’re not tracking an activity – the expected battery life is 11 days without solar charging and 14 days with solar charging. That’s a 27% increase. Not bad."

A 27% increase can't be broken down moment to moment and reported? How is a 27% increase achieved if it's based on a 50 lux hours minimum? That is, what math is used to determine 27% based on 50 lux hours? And whatever it is, that should mean that translates to a real time reportable number. Of 50 lux hours a day bumps you from 11 days to 14 days, why not report that number on the screen as "added days" or "added hours"? A metric that's meaningful.

Locked-N-Loaded said:

How is a 27% increase achieved if it's based on a 50 lux hours minimum?

bluefish said:

…“According to Garmin, these battery life specs are based on the assumption that you wear your watch all day, that it is exposed to full sunlight, and that you reach a total of 150,000 lux hours per day.“..

Locked-N-Loaded said:

why not report that number on the screen as "added days" or "added hours"?

Because it is not real-time data. The solar cell transfers the energy to the battery. This is stored there.
Incidentally, another real-time calculation itself would also consume energy, as this requires additional processing power.

150k per day BUT for how many days to get a 27% bump (3 extra days)? 150k for 15 days, 30 days?

AND if they can determine this, my original overall total point still stands. Why not provide a screen that reports a meaningful real-time number? If they can figure that, they should be able to break that down into a moment to moment real time number. It's just a different calculation.

Fine show me 90 lux hours. But then, like all other screens with data numbers, allow us to flip to another screen that says "4% battery life added" or "3 minutes battery added". With a chart or something (like Lux hours has) of the variability based on what functions are running.

Locked-N-Loaded said:

Why not provide a screen that reports a meaningful real-time number?

bluefish said:

Because it is not real-time data. The solar cell transfers the energy to the battery. This is stored there.
Incidentally, another real-time calculation itself would also consume energy, as this requires additional processing power.

Consider all of the metrics that are used to determine training status or training readiness or hill score or endurance score or recovery time. You're telling me the dozens and dozens (if not hundreds) of calculations needed to determine each one of these numbers which is broken down into a number for you to make it meaningful for you that the same thing can't be done with lux hours? 

That logic doesn't fly.

Useless.... Because it's still quoting the fundamental problem. It's still quoting lux hours. A number that means nothing to anybody. It needs to be broken down converted and translated into a number people can understand. 

Consider a "light year". That number means nothing to anybody it has no reference point. But if I tell you a light year is 186,000 miles (300,000 kilometers) per second. You now have a real world understanding of a "light year" in terms you can comprehend.

Nobody knows WTF a lux hour is, means or adds to the watches battery. Let alone what it even is  but if you can say 50 lux hours is 3 minutes saved (or added) NOW it means something.