I found that solar panels are virtually useless while riding because they need full sun at the correct angle to achieve anywhere near the stated output. I prefer riding in daylight and taking rainy days off so that limits the time for full sun static charging. Do note that my experience is from 2008.
I use the
HyperJuice Mini and charge it every 10 days or so. It's 9 ounces including charging cable to charge from a standard outlet.