I am wanting to build a power supply for an amplifier and was wondering if a transformer out of a large battery charger would work. Transformers are so high when you can find them that it is not practical to buy them. I am wanting to build the amp and power supply in one box. You can buy them at Sams for less than $100.00. They are rated at more than 100 amps. If anyone has had any experience with them let me know. Thanks in advance