Solar power with Ring Doorbell 2

I have a Ring Doorbell 2 that I use on the gate of my property. It is not near any power supply, and the doorbell is on a post that faces directly north (no direct sunlight). I seem to get a week or two on a battery charge, but it's still a pain to have to go change the battery. I'd very much like to use a solar charger, but the one that Ring provides for the Doorbell 2 mounts BEHIND the doorbell itself, which, in my case just won't work. If I could use a solar PANEL solution, I could easily mount it on OTHER side of the gate post which gets all-day direct sunlight. I called Ring support, and they basically said "sorry, we don't have an answer and cannot recommend any product that might work for you." Ugh. My question is: is there any solar-powered option that will work for my Doorbell 2 in my circumstance? And yes, I'm asking about 3rd party options here as well. Thanks!