Originally Posted by
noglider
Really, solar panels are useful? I read the ratings from time to time, and it seems that the space required and the small output don't justify the expense. And you pretty much need ideal conditions, and it isn't always easy to drape them on your bike over your baggage. But I'd be glad to know I'm wrong. I haven't toured much recently, but I suspect batteries seem like the best bridge between power outlets. It also pays to reduce power consumption as much as possible.
I was surprised, but a lot of the newer ones are really getting up there in wattage and down in weight. Omnicharge has one for $75 that is 20W and weighs 500g. I had wanted to test them so this conversation got me to order one. I’ll let you know how it works. The last time I looked at this, you could pretty much get 7W for that weight.
With the solar panels, I think it’s best to have a battery that charges at the voltage output of the panel instead through the USB interface that they all have that is going to drive the efficiency down.