wiring a three bank pro extreme battery charger in a 2000 javelin r20

i just bought a three bank pro extreme charger and i need to connect the purple wire on the charger to a key activated 12 volt source . the tech help man i spoke with at csi said to connect it to the hot wire on the back of the tach but i have several wires going into the back of my tach because of the engine diagnostics . if anyone has wired one of these chargers up what did you connect the purple wire on the charger to. thanks, chuck

Any switched 12 V will work. You can just tap into master power line and you'll be OK. What they want you to do with the CSI is to have a sense pulse line from the charging system to start the charge to the TM batts once the cranking batt is back full.