Im trying to figure out how big of an alternator i need to get. Heres what it will be running:

3 ProComp 130watt offroad lights
2 Empi 55watt lights
2 headlights
tailights
tag light
A few idiot lights (guages later)
009 with Petronix (MSD later)

Does anyone know how big of one I will need. I have been told that I dont want the usage to exceed 80% of the alternators capacity. None of my lights say anything about how many amps they draw or what size fuse to run.

Your lights alone will draw over 40 amps. This will be your highest draw on your electrical system. I would run 3 circuits for them. One 30 amp (#10 wire) for the 3 - 130 watters, 1 - 20 amp (#12 wire) for the other 4 head lights and one 15 amp (#14 wire) for your tail and brake lights. Use a 65 Amp minimum alternater. By doing it this way you will be fully protected and if you have a short in one of the circuits you will still have lights to get you home and not a fire to see by lol.
Hope this answers your questions.

_________________
Water cooled Dry Sumped Subaru Powered Turbo Charged Fuel Injected 2500CC Tank. Oh Rah! He who dies with the most Toys not only wins, He also wears them out!

Wattage divided by voltage = amperage.
Add everything up and then give yourself about 20-25% margin.
Your gonna need a good one if you run everything at once....

_________________
Gary

Turbo VW Sand Racer
Polaris Ranger



"If you don't run into the Devil every once in awhile, you must be going in the same direction!"

Davis Motorsports FaceBook Page

Thanks guys! That was very helpful