Any chance you would be willing to share what solar charger you are using? I have a Brunton Solarport 4.4. Seems to work but I haven't actually tested how long it takes to charge. I do a good bit of backpacking myself, and I think this Brunton is a too bulky. I use it to charge the batteries for my Canon S3 IS and my Garmin Rino 120. thanks....