So I am looking to add 2 fog lights to my bumper and 4 to my roof rack, also i want to see about adding 2-120 plug ins in the rear was wondering if i need to change out my alternator for a better one? Also when i wire the head lights do i need to put a relay switch in?

 

I`m not sure what year Jeep you have but I know older Cherokee alternators were kind of wimpy as far as output. The general rule of thumb for power needed falls under Ohm`s Law which is Volts x Amps = Watts. So basically a 100 amp alternator running at 13 volts will theoretically run up to 1300 watts of stuff (But that`s the upper most limit of the equation as nothing is every totall efficient) I`d add up all your stuff running and calculate. But it never hurts to have a stronger alternator than you need.

 

try a 136amp alt out of a v8 grand cherokee.