For sale is a Celestron Lithium Power Tank. It was only used for a few months. I love the battery life and size, but I need to upgrade to the larger model to operate my CPC and dew controller. This battery straps to your tripod leg, contains a bright light (red or white), and can even charge your USB devices.
The black end cover is no longer connected, but it's easy to attach and remove.
Additional details: https://www.celestron.com/products/powertank-lithium