What Jeep do you have? If it's a YJ then you'll probably want to run another line from the alternator to the battery. The stock line is rated at 100a (two 50a fuses in the PDC). Although, that's at full draw and at high RPM. So yes, you could run it without upgrading in a pinch. You'll want to look at the load range of the wire gauge to figure out what you need. A 10 gauge wire would work but if you're going to do it you might want to consider something like a 8-4 gauge. Then fuse that or use a circuit breaker.
