I have seen switching power supplys on ebay 13.5v 30 amp I have seen that you can combine these power supplys so you can have more amps but must have some type of resistors to help regulate power supplys so they can be as one and not fight one another for supply. These power supplys are about 40 dollars a piece but if you combine 3 that will be a 90 amp supply for under 150 dollars or combine more for more amperage. I have seen one already done but he would not let me look inside to see what has been done. Any suggestions the supplys are model S-350-13.5 Thanks Jimbo165