Sounds reasonable enough, especially if you work with the traditional correspondence of wand being Fire.
I've never charged anything with sunlight before though, so I can't really give you any suggestions on whether or not just leaving it in the sunlight will work or if you need to consciously focus it or what.
True, though in this case I wouldn't suggest moonlight. The two most common elemental attributions to the Wand are Fire and Air, both being masculine elements. The moon, being feminine and all, really doesn't jive too well with that.
There are certainly cases where moonlight would make sense, like if you're from a particularly feminine tradition or are making a wand of some feminine element, but your "standard" wand would do better with sunlight.