The best way I know is to measure a strip that is just about as long as the car, and cut it off. On one end, the "leading end" fold the tape over on to itself (about 1/2 inch) Take this end go down through the chassis, until about enough tape is left at the trailing end to cover 2 cells, continue around the bottom of the chassis, come back up loosely. Leave a bit there at the that corner, now put in the battery and hold in it in and position where you want it. Tape the first two cells down with the trailing edge of the tape, now unstick the tape that is on the bottom of the chassis and pull it really tight, toward the leading edge end of the tape, now un stick the tape that is stuck to the battery near the leading edge and pull the tape TIGHT! You should have just enough tape to make it back to the 2ed cell you taped in with the trailing edge of the tape, cut it off if you have too much you do not want it to start to go back down again. Now if you hits lots of things, repeat for a second strip of tape. Make sure you are using some good strapping tape. I like the ~1/2 inch wide black stuff. Not sure who makes it, but it sure is sticky and very strong. It is much better than just plain old strapping tape from the hardware store.