NiCds are ideally suited to stuff like starting helicopters, where they are required to spin up the engine and the rotors to starting speed before the ignition is actually switched on. They are usually sized so they can do it exactly twice, and then you are stuck looking for another power source.
I.e., they thrive on use and abuse, so be sure to be very rigorous about scheduling and conducting generator startups.
NiCd battery assemblies are usually sized so that a decent lead-acid charger of the same nominal voltage won't kill them. Some of the fancier industrial chargers will have a switch or other adjustment for battery chemistry. Check that the charger you are being offered is documented to work ok with NiCds.
Mike Halloran
Pembroke Pines, FL, USA