Solar Power Supply for Weatherstation or any device needing 3.3v

I have a weather station that runs on 2 AA batteries which lasts for about 4 weeks and I thought it would be a good idea if I could make a solar power supply.

Note this same design could be used to power almost any device that needs 3.2 volts,for instance an Arduino based weather sensor you make yourself.

You can replace the Buck converter I used to generate almost any voltage required.

I used the 500mAh battery from a quad copter I already had, but any 3.7 volt lithium cell can be used