I'm intrigued with solar chargers either for camping, travelling or cycling. But realistically, they are impractical. They are heavy so for camping it's better to carry spare dry cells and battery packs- how long are you gone for anyways? For travelling, you'll find and electrical outlet in your hotel room.
If you leave your solar panel out unattended, it'll get stolen.

For cycling, carry spares or get to a coffee shop.