Make sure you are looking at 12v DC power supply's rather than Transformers. I run a 20A pro-peak supply, does me ok for indoor racing with 2 chargers, motor cooler etc. Best thing to do is check with a multimeter the current draw of all of you equipment individually, then you will know what you can load up at once. Much more motor coolers draw about 4 amps and tyre warmers can draw quite a bit as well.