Is there a trick to remove the red positive terminal from the old battery? I cannot get it to come off and the video is no help.
above may be better. Click on the unit you have.
the below is another link.
It can be removed with needle nose pliers with care...
They are on there pretty tight, but you shouldn't need any special tools to do it. I've heard about people using needlenose pliers, but you'll want to be super careful doing this as the battery is still carrying some charge!