The roll eyes I put in there because... It seems to me, people are making it way more complicated than it really is... One needs to figure out how long one needs/wants to be able to go without plugging into a wall for power... The solution is varied... One can use less power, one can make some power, one can carry more power, one can do a combination of all... So, IMO the easiest way, is cut to back on power usage, and carry some extra battery power to extend the day's you can go without plugging into a wall socket... Once you go down the road of generating power with a dynamo or a solar panel... The $$$ one spends to accomplish the goal can be huge... And the goal could still be left wanting...