Dont buy another GoPro battery until you have read this!
Last year I was searching for a spare GoPro battery for my Hero2 cameras on Amazon.com and came across Wasabi Power. The kit included (2) Wasabi Power batteries and a Wall/Car 12V charger for $20.00. I figured what do I have to loose going with that option since the new GoPro battery was $40.00.
Turns out this was a great purchase. I have been using it over a year now and it will charge a dead battery in about an hour and a half which beats the USB cable. I can now charge on the go with the 12V option. The batteries last as long as the original GoPro batteries. This is an excellent alternative.
Wasabi Power also supplies batteries and chargers for Hero3 & Hero3+ cameras.
Although from what I understand is they are developing a new charger for the Hero3+ batteries due to the 2 notches that have been removed from the Hero3 batteries. They also produce batteries and chargers for other photo and video devices. Check out their Facebook for more information and links to the charger and batteries you are searching for.