or go to the local welding supply store
http://www.ebay.com/itm/12V-DC-CAR-...Parts_Accessories&vxp=mtr&hash=item5d2f9dac33Again(if you read)..some people put a fuse in there and others say it's not necessary. I haven't found anything with a 150amp fuse or circuit breaker yet. 80 amp was the largest car stereo fuse I've found so far.
For those that are fine with 4 gauge and want a cheap (~$13) easy way to do this upgrade, you can do what I did when I did my AD244 alternator upgrade. I used pre made 4 gauge switch to starter cables found in the battery section of stores. The 24" was from Walmart for $4.44 and the 19" were from Meijer and were $4.29 each(I used 2). The 24" went from the negative battery to the existing frame ground from the battery. One 19" went from the positive battery to the charge lug on the alternator. The other 19" went from the alternator bolt to the frame ground. I may move this one to the existing engine block ground at some point just to clean up the area a bit.
Stock frame ground location. I just used a longer bolt to bolt the 2 new cables in place.