BionX 24 NiMH replacement pack?

Has anyone had success just replacing the cell pack in an older (I2C) BionX PL-250 24V NiMH battery? If so, what cells/pack did you use? I don't have access to a tab welder, so a prebuilt pack is required.

Thanks
-Krazykraut

not 24v but did a 36v nimh to 36v lithium in a rear soft pack.

the electronics would be easy, physical size is challenging.