G1 solar efficiency

Hello all

I bought the G1 solar about a month ago. So far I love it. However I am not sure the solar option is doing anything. I am currently in Costa Rica and the solar intensity graph is showing a lot of maximum values as I am out and about and it is super bright. However I do not see any improvement or recharge at all. The battery still going down day by day. I have the standard display on and not use any activity etc.. 

how long do you have to keep it in the sun to actually get an additional day out of it. I read somewhere it is 1h sun for 3h runtime but not sure this is correct.

I certainly was expecting to regenerate some power, not sure why some reviewers mention infinite run time. 

has anyone ever seen the G1 battery run time to go up? 

thanks!