at 150 amps im surprised you didnt burn a hole in it. figure out your total square inches and then use .2 amps a square inch of surface area and i think you will be just fine. if your using a bettery charger i dont think you will ever get the result your looking for. check out my web site for some items i have plated copper both acid and alkaline and acid nickel . i have never used more than 5 amps on any of the parts.
http://www.home.comcast.net/~jhodges87/wsb/index.html
bill