This weekend we got a call to jump start a bus. The coach was what looked like a old mci bus. After about 30 minutes of stanby with the cables on the coach the unit still would not start. We finally figuered out that it was a 24 volt system. Can we cause any damage trying to jump start it with a 12 volt system. I dont think there are many 24 volt trucks out there. And is there any procedure if any to joump start these vehicles. Any input appriciated.