"Lux hours" doesn't mean anything

Because we all need a better metric that what's shown us.

Locked-N-Loaded said:

How much battery was saved/gained?"

I repeat myself. Lux hours describes the value that the solar cell has collected during the day and delivered to the battery through its collected energy. It is a cumulative value over the day.
How much this contributes to covering the energy consumption of the watch depends on an extremely large number of different factors. Among other things, the temperature, which watchface you are using, how charged the battery currently is, whether you are recording an activity. HOW you record it. Whether you have connected external sensors. Whether you have activated Bluetooth, whether the optical sensor is active, whether it is in low power mode or high power mode, whether you have activated second-by-second recording, the brightness of the display and how often the backlight is activated. A not insignificant consumer is the map page in a MIP display. and so on. Because a MIP display consumes battery when pixels change, the first Enduro didn't even have maps. A static display on a MIP display does not consume any power. When pixels change their status, they consume power. So the display factor alone can contribute to a not insignificant change in the current required by the battery within a very short time.

Last but not least, the age of the battery and the number of charging cycles that have already taken place are also decisive factors in determining the real capacity of the battery at present.
Schmjoe has already sent you links that should answer your questions. There the question of WHAT lux hours are and how many lux hours are needed to gain 1% charge is clarified.
I have also already tried to explain this to you.

According to Garmin, you need 150,000 lux hours DAILY in order to fulfill the specifications by solar charging in the respective modes.
In real terms, this means for the Enduro that the battery is not charged during a GPS activity, but only discharged more slowly.
An Live algorithm would have to take into account all factors that change constantly. When you go running, you are constantly moving your arms. The angle of the solar cell to the sun is constantly changing. Shadows fall on the cell. On a forest run, the light changes in a fraction of a second when the sun comes through the trees and then is shaded again.

As a result, an algorithm that gives you a live result would constantly require CPU power and thus consume extra energy. You have ignored this point so far. And what good is a live result if it is no longer valid the next moment because a cloud suddenly obscures the sun?
The value that you want (information on how many percent battery I gain at, for example, 50,000 lux hours) would only be meaningful when the watch is switched off, as there is then no consumption. If the watch is switched on and does not track the sun continuously, there are too many factors. Both the charging current to the battery and the discharging current through consumers vary constantly, so that even a real time result tells you nothing about the near future.

Please bear in mind that you are discussing an Enduro 2 here. A watch that is designed for battery life and for this purpose has a lower CPU clock than other watches such as the fenix. You will meet enduro watches at ultra races. For example, the Cocodona 250, a 250-mile race through Arizona.

If you think it would still make sense, go to the Gsrmin "share Ideas" website and suggest it to Garmin.

Locked-N-Loaded said:

I already did "share my thoughts" with Garmin & their tech support. Who, unlike you, actually admit they see the logic in my suggestion.

Good, then you can relax and wait for Garmin to implement your suggestion.

Locked-N-Loaded said:

Nothing more needs be said.

It is a very interesting discussion and I agree that the solar display in Lux-hours is useless.  I have tried to think of what else it might be useful for but the only thing I could think of was whether I should put sunscreen on, by which time it is too late, but a warning could flash up if the sun is strong maybe.

Battery % remaining is related to the voltage measured at the battery which varies between an upper and lower limit set by the battery management system.

The % remaining changes as energy is consumed by the watch and/or replenished by the charger and/or solar panels.

If the watch knows:

1) the power provided by the solar panel in real time

2) the power consumption of the watch in real time

3) the relationship between amp-hours consumed/charged and the change in voltage at the battery

then it would be possible to give a meaningful report in terms of battery % e.g. "Today's solar contribution 3% battery capacity"

We know it knows 1) because that is directly related to the Lux hours that we currently have, 2) possibly and 3) changes during the life of the battery so not sure.

In any case this is right up the street of Garmin's hardware engineers who have always been laser-focused on ultra-low power consumption so I expect they would enjoy the chance to try and implement it.

*** yeah.. you get it

PubBike said:

If the watch knows:

1) the power provided by the solar panel in real time

2) the power consumption of the watch in real time

3) the relationship between amp-hours consumed/charged and the change in voltage at the battery

then it would be possible to give a meaningful report in terms of battery % e.g. "Today's solar contribution 3% battery capacity"

We know it knows 1) because that is directly related to the Lux hours that we currently have

You are neglecting the following points :
1) the temperature of the battery - the higher the temperature, the higher the displayed voltage - chemical-physical process.

2) Lux hours is not a current value, but a value over a period of time.

3) the age of the battery. Have you noticed that a new LiIon battery apparently charges to 100% faster the older it gets? This is typical behavior for LiIon batteries. The reason is that the older they get, the more capacity they lose. The charging behavior of a LiIon battery therefore changes the older it gets.

1) the onboard temperature is known. So battery life can be determined because it is displayed so that means it's taking that into consideration if that's actually a factor at Play.

2) that's debatable I actually installed a data screen for solar that shows a continuously changing battery usage amount per hour & per day.

Every piece of data that is needed to conduct this calculation and convert it is collected and is onboard and we know this because those pieces of data are used in other screens.

Locked-N-Loaded said:

Every piece of data that is needed to conduct this calculation and convert it is collected and is onboard and we know this because those pieces of data are used in other screens.

No

bluefish said:

the age of the battery. Have you noticed that a new LiIon battery apparently charges to 100% faster the older it gets? This is typical behavior for LiIon batteries. The reason is that the older they get, the more capacity they lose. The charging behavior of a LiIon battery therefore changes the older it gets.

A 1% charge on a new battery is therefore not equivalent to a 1% charge on an older battery in terms of the energy supplied to it.