Your link on building a solar charged arudio is overly complex if you instead use AA Nimh batteries.Below I will cover how I build a solar charger. Very simple and works. Trying to get those fancy battery banks to work has seemed like too much work. In addition once you have hacked it into working some people complain that the voltage fluctuates and hurts their radio transmission power.
I read your links, a very interesting project. Sister saw me reading the links and told me to order the scale for a birthday present and to build the project for one of our hives. So I will be building one in the near future. Have you built any part of this yet? I am wondering how a person puts a humidity sensor in a hive without the bees plugging it up.
I have thought about the problem of the bees building over the sensor, but haven't come up with a concrete solution yet!