They do say "Gates" on the bottom of each cell, they are quite a bit larger than a "D" cell and have two terminals on top
The only thing holding the packs together on these is the orange label, I sliced it with a knife and the case pulled right apart.
The wife of one of the guys at work has a battery business specializing in rechargeable cells. I'll ask her if she can get me some replacement cells.
I have a Panasonic TV from the late 60's that uses a large lead/acid gel cel, that one would be a mess/impossible to open up! (see pic)
