I've installed a external regulator kit in my 99 xj. From day one it would spike up to 15.50 volts at times. My gauge would peg all the way out. The only way I could see my real output is hook a voltage meter to battery. I have double grounded the regulator with two wires going from regulator to alternator instead of one. It still would do the same at times. I decided to install a real mopar regulator in place of the aftermarket unit I was using. It fixed my problem for a couple of months but i noticed the last time I drove it it spiked again while it was sitting in idle. I am tired of dealing with it. Anybody got a solution to my problem?

 

Repair it correctly?