... four 6's ?? i'd swap that to two 12's if possible, makes having a batt charger a tad easier.
One of the important skills for an engineer (or wannabe engineer) is the ability to correctly decide when something merely needs repair vs. needing redesign.
Odds are, this scissor lift uses four golf-cart batteries, a popular format that offers good price and availability due to economies of scale. There is a battery box with holddowns configured to fit GC batteries; swapping something different would require changing the dimensions of the battery box and holddowns ... or were you thinking about just plopping them in there loose? Then the cables would need to be reconfigured, both the battery and charger cables. You'd reduce the weight of the lift and raise its center-of-gravity, invalidating the stability calculations that were performed when it was designed.
Or you could replace the non-functional 24-volt charger with a new one. 24-volt chargers are readily available and only occasionally need replacing. They're not a consumable item; there's no need to substitute something that's more widely available.
The original post was about a quick fix to enable finishing up on a jobsite while the replacement charger is in transit. And a suitable solution has been shared: two 12-volt chargers and no wiring changes.