I2 Solar - Normal battery usage?

Battery discharge is not linear. 7% without gps is enough. I have my watch turned off to monitor SPO2, brightness 5% and if I'm in the sun a little, I gain. Try installing the Batt Guestimate application and you will see it beautifully. I would definitely drain the battery below 20% and then let it charge to 100% and continue charging for another 30 minutes or so and then you'll see.

Why continue charging after 100%?

My experience with all versions of Instinct Solar is that if I stop charging at 100%, in an hour it is already 99% and less, if I continue longer, I have a much longer state of charge, still 100% or 99.5% in the morning. Try it, you'll see. I think the charging continues, I can also see it when measuring that the watch is still taking power.

That is interesting, I think it is normal that modern devices don't really charge up to what the battery is capable to store, but show 100% before that point. But I would have expected Garmin also then to stop charging, because the whole point of it is to reduce the wear on the battery.

Btw, thank you for suggesting my Battery Guestimate widget 

It's not just Garmin, I noticed it on the phone. There are also applications directly on the mobile and show 100 %, but that there is still a charge over 100 % and the device really holds charge longer. Today, the product is competing for how long (fast) is charging up to 100 %. Who knows how it all is. But I tried it mainly for IS Solar and IS Solar 2, as soon as it is 100 % and disconnects, the battery goes down ... when I charge for about 30-60 minutes, holds 100 % and then goes down slower. Yes, it should manage and regulate it somehow, but my experience is just like that.

Hi, thanks for your feedback. 

I will try to charge it that way at the next cycle. 7% is not bad  ( today I’m on par with that after another 1h and half no gps activity ) Since it’s the same usage as my old Fenix 6 I just maybe expected something more. 
I already have Guestimate widget and it’s very good! 

Yeti said:

I think it is normal that modern devices don't really charge up to what the battery is capable to store, but show 100% before that point.

No, they probably do the opposite. Especially mobile phones.

Yeti said:

But I would have expected Garmin also then to stop charging, because the whole point of it is to reduce the wear on the battery.

As the exact charging method is not known, I think the best would be to charge only to 90% (quote from link: "Lithium ion is ONLY dependent on end of charge voltage"). That means doubled battery life. Of course it depends how long does the user intends to keep the watch in use.

I think we are saying the same thing.

If the manufacturer knows the battery will die quicker if always charged to 100%, just don't let the user ever do it. Let the charge go up 90% and display 100% to the user.

But maybe it depends on what the manufacturer wants to achieve, claiming a long time the device is able to run on one charge or having the battery surviving mire charge cycles

Yeti said:

But maybe it depends on what the manufacturer wants to achieve, claiming a long time the device is able to run on one charge or having the battery surviving mire charge cycles

Yes, I think you defined well. Li-ion battery management is a trade-off between operation-time and lifespan. At least everybody has the opportunity to charge it to 100% (probably resulting 4,2V cell voltage) to have maximum operation time or disconnect it at e.g. 90% to prolong battery life. It's up to the user.

But regarding I2 which is probably charged every week or so, 80% battery capacity in ~6 years from now is still acceptable in my opinion.

The question is whether it is. I had an IS Solar, I charged as I wrote and after two years the same endurance, I always charged below 20% and up to 100% and a little while after that. Nothing went down, in the morning after 12h still 100%, if I unplugged when it reached 100% then in the morning it was 97%-98% which is a bit weird. I don't think the battery is destroyed like that, if it is charged, no more can go into it. It can be measured if the meter showed me that the battery was still charging, so I continued, it was about 30 minutes after 100%, then it stopped charging, so I disconnected it. After 2 years of using both IS Solar and 5 years of using a mobile phone, I don't see a negative. Six years is on the watch is very old...