Is Solar charging bad for the battery?

KrapfenKringel said:

Since its known that a lot of short charging cycles are bad for the battery

This is not true for Li-Ion batteries. You can always REcharge Li-Ion batteries in between without damaging them.

The most important thing is the charge level in %, which should be observed. At a charge level below 20% and above 80%, the decay of the chemistry accelerates.

With Li-Ion batteries, one always speaks of charge cycles. It lasts - depending on the type differently - for example 500 charging cycles. However, this does not mean that you can only connect it to the charger for 500 times, and after that it is broken. If it says 500 charge cycles, then it still has about 80% of its initial capacity after these 500 charge cycles. He still works. But not so good anymore.

One cycle corresponds to 0%-100%-0%. Until you have reached that by short recharging, a lot of time passes.

Are there any differences in readability between solar and non-solar version? The Instinct solar seems worse, but the this one is not really comparable to the Fenix series.

Think of it like a Hybrid car. Like a Prius. It's constantly switching between charging and discharging, many times per minute. Batteries still last for years. I don't see how the watches would be any different, it's more or less the same kind of battery.

I think that Solar version does not actually charge the battery but when in bright sun light, watch uses more solar power instead of battery. You can test it by leaving watch to sun light and check if charge level rises or not.

A lot of people used to think that, but it's been disproven.

It's true that the solar panel doesn't usually provide enough power to compensate for the drain that occurs simultaneously, however if you drop the watch into super-low-energy mode and turn off all the sensors and radios and everything, then it will (very) slowly charge the battery. It's been shown on a few youtube videos.

So in typical usage, it effectively does only offset the battery drain. But the circuitry is there for battery charging, all that's missing to effectively charge the battery is a panel big enough to collect more energy than the watch uses. The instinct has that, and we're thinking the Fenix 7 probably will too.

In my little experience yes, they look different a bit... The solar panel that covers the screen (the "10% efficiency" part which is transparent and covers the actual display) make colors a bit darker and somewhat less readable if illumination is low, no big difference in shiny light, and... Makes the display look better when backlight is on, since black looks deeper.

Also, for the solar the display looks as it's more embedded into the device, possibly due to the additional thickness of the solar panel over it.

I kinda prefer the regular one better looks nicer when backlight is not turned on, which in the end is the beauty of the transflective display.

This however is based on a single Fenix 6 solar I had the opportunity to see in comparison with other 3 or 4 regular Fenix 6 ,could be luck of the draw for the specific watches and not general, I am not sure

As it has been said the Power Glass on the Fenix 6 Series (or Tactix/Quatix) is not made to recharge the battery but to help the battery by being another power supply. Only the Instinct Solar has shown real signed of recharging with the Infinite Sign displayed.

Now Casio (for example) has been proposed solar tech on their G-Shock watches since 1998 with their Raysman.

Is Solar charging bad for the battery ?
I have bought my Raysman in 1998 and it still going strong on its first battery. So it is 23 years old on the same battery using the sun light daily.
From my own experience solar charging is not bad for the battery of this old watch.

Picture from the 5th of November (remember, remember the 5th of November!), my Raysman on the left posing with my new B5000TB)

There are alternatives too charging the battery, you could also charge a capacitor.

Yes KrapfenKringel, of course. Solar Panels Juice can go their own way to the "engine" of the watch.
Casio got "button rechargeable batteries" and Fenix seems to have "Capacitors". 
No need to play with words. You could charge "anything" and the question was about "battery" in regard of way they can react to "over charge" (the law of 80% max to keep them in good health)... ;-)

Yes that was the question and you talk about some old Casios that do this for years (I my still own a 15 year old Casio solar that says its power source is fine). But I suspect they didn't have the batter technology of today and used capacitors, anyway I'm not sure.

But as stated in other posts it also seems its not a problem for modern batteries (Just those old Casio's might not be a good example for that).