Ebay offers Cuddeback Super Solar Power Bank for Trail Cameras for $93.88 (reg $139.99) with free shipping.

Product Description:
The Cuddeback Solar Power Bank allows users to extend the camera's runtime indefinitely when placed in adequate ambient light. LED lights show the user power status of the panel allowing for easy use. The user connects the solar panel to the camera with an external cable.

Features

• Allows users to extend the camera's runtime
• Runtime is indefinitely when placed in adequate ambient light
• LED lights show the user power status of the panel
• Works with all CuddeLink and Tracks cameras