I don't get it

[stan03]

How are rehobuses rated for voltage? example the sunbeam says each channel can handle up to 20 watts. but this it says its adjustable form 0-12 watts... so how do you get from 13-20?

[RoadWarrior]

I think it probably says 0-12 Volts.
P=IV
or
Watts = VoltsxAmps.

So, for a 12V fan, the max amperage it could handle would be
W/V=A
20/12=1.66A, which is probably at least 6 regular fans, but if you've got high speed screamers it's probably 3.

Alternatively since they give a wattage rating, and you are using a lower supply voltage than 12V for your fans, you could use more fans.

Hmmm looking at my fans some have wattage quoted, some have current draw quoted. The 30cfm Sunons I am looking at here are only 1.4W so you could have quite a few of those controlled.

regards,

Road Warrior