I have noticed that I'm still charging the batteries on partly cloudy days.... certainly not as effectively.If the timing / price / availability of home solar ever works out in my favor, I'd love to look into it.
The good thing about this technology is how efficient newer panels are at generating electricity in lower-light situations.
Here in Indiana, we're cloudy like 60%+ of the time (on average, per year). I'd bet that the newest panels can probably come close to generating the same power on a cloudy day as older panels used to produce on a sunny day. To me, that's pretty incredible.