Zamp and RockPals
First, I'm not a solar expert. I had a Zamp solar suitcase with 90 watts to charge my Five Wide Rough Rider. I'm sure it was fine, but was awfully big and heavy. I had a hard time fitting it in for trips, and I'm usually in shade anyway. I sold it. I still have a single (with no controller), same size, but only 45 watt and half the weight. I'm not hauling that around either.
The RockPals 100 watt, folding solar panel doesn't weigh much and is much smaller and less expensive. I cannot plug it into the Zamp connection for the battery, but it does work fine for keeping my Jackery 500 charged. It is not waterproof, but if it's raining, it probably won't charge anyway. It can also connect with a second one if a person wanted two hundred watts. It has fold out things on the back to set it at an angle on the ground, or I could unfold it up on the roof basket and is not too heavy to get up there.
I rarely go where there are hookups, but I feel like I can stay out longer if I need to charge the phone, the electronic reader, camera batteries, maybe a little laptop.