I have some older UPS hardware that the devices themselves should be fine but the batteries are shot. The most painful part of this is when they have decided to expand and trying to get them out without bursting the batteries or damaging the actual unit. I may have a bit of a night ahead of me sadly. It is an APC Smart-UPS 750XL and the add-on battery pack. I think the add-on pack is fine but the main unit that controls everything has the bad batteries. Gotta take them both apart to find out What all can be replaced. I do know that the main unit will not work without having batteries itself. The add-on unit cannot do all the power while the main unit does all the regulating. I wonder if they both have the same battery types. Something to ponder while taking this apart.
addendum(06/27/2017): Looks like the secondary battery pack had a set of batteries that in the past had leaked…on the inside of the case… So I chunked that. I am keeping the main unit because when money is available I am going to buy replacements and start using it again. Oh well. Back to the drawing board.