I took two Exposure Joysticks and a Diablo, and I had some Piggyback batteries for those that I could also use to extend the range on my Garmin. I could use the lights as chargers for the Garmin as well
This, I think:http://www.chainreactioncycles.com/Models.aspx?ModelID=70087&utm_source=Google&utm_medium=Shopping&utm_name=UnitedKingdom&gclid=CKOZqbO91LUCFeXLtAodfGMAywI've been considering trying one.