Powering a motor cooling fan

[stuey]

Hi guys, quick question. I want to add a motor cooling fan to a TC, I was going to use a spare ESC fan I have. Usually the fan would be powered by the ESC, but does it power it directly from the main battery, or from the BEC which feeds the radio? The speedo does not have a power feed for a fan, as it does not have that option.
Cheers