Why not just get a cheap power supply? Here's a link to one, the one I use:
http://www.emtel.com/search/product_...t_id=EMV15012V
EDIT:
It looks like they may have raised the price a little bit. Even still, it is rather inexpensive.
SH Z-Car, Custom Crawler, 8s Savage,
12s XTM XLB 1/7 buggy,
4wd 4-link rear/IFS Pro4 truck,
Custom Hyper 10 Short Course,
Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz