I have a 100 amp alternator. Now I know that's not a lot. I just put a system in my truck, upgraded my 60W head lights to 65W, and I bought 100W KC off-roading lights.
Is this too much to run on a 100 amp alternator?
In August my old battery leaked out and my truck died. When I had that battery my interior lights would always dim whenever I applied the brakes, opened or closed 1 window, when I turned my steering wheel and even when I turned my head lights on. So I had to change out that battery and the interiors stopped dimming for most things, but they still dim when I apply the brakes.

Will adding these new 100W lights be too much for a 100 amp alternator?

 

first thing to try....upgrade the "Big 3". if you still get dimming on bass hits then think about upgrading. What amp are you running with your system?

 

it sounds like you have a bad ground, if the lights are dimming by pressing the brake. Do what Jimmy (jab) said and at least upgrade the ground from batt to chassis and engine to chassis.

 

I don't have an amp or sub yet. I couldn't afford that so I'm waiting that out. I was looking at some L7 subs and pretty powerful amps though.

 

Yeah, with a low-end stock alternator I don't wanna put too much on it. Next thing I need is a dead battery.