I am looking to add some additionnal driving lights on my JK but I don't know how much more amp draw I can get from the stock alternator and battery setup. Can anyone enlighten me on that topic? Does anyone else have pictures or descriptions of their setups? I am talking about 4-6 add lights.

Thanks!

 

It is relatively easy to figure out what you can pull of a stock alternator.

Let’s figure 100w set of lights (nice round number) the power required is 100w and the voltage is 12 Volts. so 100 Watts divided by 12 = 8.33 Amps. That’s a "little" off as your shit is not ran at 12v exactly its around 13.5v to 14v. 13.5-14ish is normal when your engine in running and the alternator is working correctly. We'll use the 12v as it gives you some buffer and is predictable.
Say you have four 100w lights and you’ve upgraded your OEM Lights to 100w each for another 200w. Now you’re at 600w, or 50 Amps if you have all your shit on at once.
Other stuff:
Radiator fan 10-12 amps
Heater fan 8-12 amps
Marker/stop lights 6 amps
Fuel pump 8amps
Ignition 10-12 amps
the list goes ON

Catching on here?
Stock alternator is what 65 amps? Yes your battery can handle the amp load but what happens is the bat can't keep up and then the alternator cant keep up.
Mind you this is when everything is on and some people will go "I don'ts gots everyting on alls at once !!" ummm ya..
Wait till you are in the winter in snow at night.
Lights, heater, wipers....you get the idea.

Just keep this in mind with your upgrades

 

... and winching an FJ out of the ditch.

 

Please correct me if I'm wrong, but I thought I read somewhere the alternator was rated at 160-165 amps. If this is correct, I hope it helps.

 

That sounds about right...

 

I have a copy of my window sticker from my Unlimited X. The Alternator is listed as 160 amps, battery 600 amps.

 

Thank you for the detailed breakdown of how the amp draw works.

If I upgraded my headlights to HID and thus lowered the wattage draw to 35, does this get me under the maximum allowed by the stock alternator? Also, what kind of setup does the KC JK has (I believe its KC)? I noticed it has some heavy lighting mod done to it. Is there any way to beef up the alternator and battery without taking the risk of voiding the warranty if something goes wrong? I would like to keep the new JK on the safe side.

Thanks for your input guys!

 

WOW that is impressive, I thought it was a lot less