I ' ve put hot shring tubes (double) around the end of the two cables and I've connected the cables with two wires 2.5 mm from bronge soldering wire. I put the wirew in a ceramic cable connector and to the ather side i put two pieces of th same wire aw like electrodes (to be easy to change them (you can also use nail from bronze or copper (after you cut the head) but I didn' t find it at the local store.It' more correct to use a battery between 35-40 Ah. 200 A of short circuit current is enough and the use is more soft (here is a little violent). The battery must be in a good condition (not very old). it' s better also to put a 10 W fuse in serie to the coil (only here not at the high current).