I see solar charging as more of a convenience than trying to go green.
The main drawback is the additional weight rather than cost.
Charging does not have to be limited to only while you ride. Your bike still has the battery, good for a couple of days commuting before recharging. Progress in solar cell will continue boost conversion yield and reduce weight for years to come. When I got interested in solar cells, you could only get about 100W/sqm at peak irradiance, now we get up to 20%-22% yield and in some situation, you can use mirror to concentrate the light onto a chip, with even better yield.
The main drawback is the additional weight rather than cost.
Charging does not have to be limited to only while you ride. Your bike still has the battery, good for a couple of days commuting before recharging. Progress in solar cell will continue boost conversion yield and reduce weight for years to come. When I got interested in solar cells, you could only get about 100W/sqm at peak irradiance, now we get up to 20%-22% yield and in some situation, you can use mirror to concentrate the light onto a chip, with even better yield.