Note: In the early version of this report which was published, PPF figures were incorrectly shown as 56 in Ring and 43 in the Nest Cam. This was based on the width of the license plate in the Nest Cam (12"), not the actual angle of view/field of view calculation, which results in 27 PPF.
They would drain that pretty fast I think. You would need a much larger solar panel a large deep cell 12V battery to make it work and even then you would probably get drop outs on cloudy days and during night time.
I think the ring cam is designed to only be powered when it senses motion or when it is remotely viewed. That is how most of the "completely wireless" cams are designed, such as the arlo. What makes this one cool though is you never have to change the battery.