Hi Bob Marley,
I agree with Charles with tape as well. I set one of my cars up with a Xray strap ( pics bellow) and the other one with no strap. The best part about using tape is you don't have to chop into the chassis and I think it is better for keeping the battery in tigh. I have had a battery come out with the Xray strap but never with Tape in Modified.
Also Bob even though this is the MSX, they are the same chassis plate and battery set up.
Good luck with your new car.
Hope this helps
Addam