My first 7X Solar Sapphire developed an issue where it ended up in an infinite boot loop, and had to get sent back to Garmin. I found another one locally at a store, and before I got a chance to send the old one back to Garmin, I was able to compare them side by side. These are the exact same model watch. Old one on the left, new replacement one on the right.
You can easily tell the solar panel on the old one was a lot redder, and the new one is a lot yellower. I assure you, it's not due to different viewing angles, the solar panel on the new one is substantially yellower at all viewing angles and in all light.
I asked Garmin if this was something I should worry about, and they essentially said "no", and said it was probably due to different viewing angles (it isn't). Anyways, not knowing which one was better, or whether it even made a difference at all, I just let it go.
But in the 2 days I've been using this new one, it seems like it struggles to get very much energy from the sun. This is a screenshot of my watch after driving to work this morning - the bright morning sun was hitting it directly during the entire drive, for 30 minutes - the watchface was perpendicular to the sun, and my window was down so it was not in between the sun and my watch. You can see, it got VERY little energy from the sun. When I did the same thing with my previous 7X, it would net 10-15k Lux hours. This time it barely got 1k. And I noticed the same thing yesterday, walking around outside in the sun, that it barely seemed to take in any energy from the sun at all.
Is it possible that the yellowish version of the solar panel just sucks? Should I return it and try to get another one with the reddish solar panel? It seems like my first 7X solar worked vastly better than this replacement one I got.