I dont know real world specs. I never put it on a tester, it always worked and I didnt care about charging 18 batteries. The car never got to play a single note though, all for nothing. The thing is the alternator is 1 of 2 that were made for Mike Hughes by Coy Hillson. I dont know what is different about them BUT a member of this forum bought one off me in the past and ran it in his truck everyday in a chevy 1500, 1999. I told him when i sold it to him its an SPL alternator etc but he didnt care if he burned it up. That was two years ago and it still runs.. So I dont know. Powermaster doesnt recomend it but they are not a standard XS Volt. Call Mike Hughes (you know, the world record holder guy 180db astro van guy.. ) or Coy Hillson (power masters chief engineer) to find out the full story. I'll give you the serial numbers or anything you need off them... I know at about 2000 RPMs it almost stalled out my civic when it kicked on. The engine stumbled, it was truely epic.