Thanks, but no thanks. The AAs in the GPS usually last for two or three days. AAAs only have half the capacity, so I would be swapping them out twice as often.

My marine band radio that I use for sea kayaking and canoeing takes 8 AA batteries, I think the batteries weigh more than the radio. I started using AAA to AA adapters for that radio, putting AAA batteries in the radio makes it much lighter. Probably 90 percent of the usage of that radio is only for weather reports which is probably no more than 15 minutes a day. Only in fog do I leave the radio on while I am on the water. Thus, I usually can go for a week without having to replace the AAA batteries.

I have never tried solar charging for bike touring, but I recently bought a couple small panels that will push out about 500 milliamps through a USB port in bright sun that I will probably carry in the future for kayak trips. Lets face it, a dynohub on a kayak trip would be pretty worthless. This coming summer I am contemplating a longer kayak trip where the solar panels could come in handy.