right now, it's in pieces.....gonna try n rebuild box for 3 18's, if the box fits--will recone my XL's to 18's. Last year, I ran 2 12v "cat" batteries and stock alternator and did a best of 157.5. First burp without changing a thing but 16v batts...no alt yet and did 158.9. The amps are/were at .7 strapped so each will see .35 before box rise...hope that helps answer your ??