I put a new alternator in last summer. I couldn't tell you what size. It's what the kid at the parts store said the computer told him for a '79 CJ7. I'm not running any additional electric except for an alpine stereo with a 40 w amp. All of the lighting is LED.
I drive the Jeep daily and The problem I'm having is that the volt meter is around 10 when I start it up in the morning. It slowly builds up to 13 or 14 after 15 minutes or so, then starts spiking with the needle going completely off chart. Over 16. The lights get bright (head lights are not LED, everything else is), then go dim with the needle dropping to 12 or so.
So I'm not sure if this is the alternator or the battery, or something in between.
It sounds to me like the voltage regulator is not working properly, or something in that circuit (sense wire). I've seen quite a few discussions here on the forum about properly connecting the alternator and also on testing the circuits to determine where a problem lies. Good luck.
Where's the voltage regulator? Is it in the Alternator? I have an HEI ignition which allowed me to remove the ignition box. So right now, my alternator is wired to the solenoid and battery. Pretty straight forward.