So, what was the end result ???
if it is an older champion battery pack you 'might' be able to use lead acid batteries but most of the ones i see now use the AGM or GEL batteries because they are mounted on thier sides. They have to be sealed so they will not leak because of the way they are mounted.
You can find these batteries alot cheaper from 3rd party battery companies. Buying them from champion or a dealer is just nuts unless you like paying twice over what you can get them for elsewhere ;o)
The lead acid pack is cheaper and tougher, but needs watering every month without fail. A single bolt in the middle holds the battery pack in, then you need a stand to lift up the pack, or another forklift.
champion 'power pack' battery packs are 4 each, 12 volt, gel filled batteries, usually 24 series batteries, but may be side mounted. the cover may pull straight up and out, or may have a bolt that is accessed in the top cover.
you will want to spend the money for the correct new batteries if you need to use this jack on a regular basis.