The specifications on the Solio website appear to be somewhat mis-leading with regard to the power outputs of the Solio chargers;

http://www.solio.com/charger/solio-charger-comparison-chart.html

The power outputs appear to be the maximum power output from the Li-ion battery pack built in to the charger can deliver rather than the PV panel capacity. Judging from the size of the panels I doubt that the PV panels supply more than 1-2 Watts if that. As most devices the Solio charger is designed to be used with already have a rechargeable battery, it might be more useful to go for a flexible 6W panel such as the Sunlinq or Brunton 6.5W solar panel costing around $5-10 more. Additional rechargeable battery devices can then be added later if required ranging from AA and AAA battery chargers to equipment specific Li-ion chargers. Many GPS devices require just fresh AA cells and don't have the facility to be recharged via a 12V cigarette auto adapter. To recharge AA cells you would just connect a AA battery charger to the solar panel.



4.5W Silva solar II + Battery charger/Power supply Unit