Originally Posted by Solara

I use your option #1 and #2 mixed......I mounted (2) GT2.1 ProStock fans, directly from the ESC batteries male bullets plug, in PARALLEL. That works out very good on no timing racing...and semi ok for boost 17.5 13.5 as it draw alot of power to the motor and made the fan slowed down by alot.

The fan can take 8.4V no problem...but don't expect that to last forever. I replaced it twice within this year...

Of course, powering from the receiver is OK too...but again, if possible, use parrallel, in series, just too slow for a 5V fan....

And your last option also work too...just not too fast of a fan if mount 2 in series....

If you don't want to replace fans...your best option is use the GT2 Pro 25mm fan and use (2) receiver ports to power 2 fans...my receiver are 5 channels so I can use all all the port to power my USGT car...1 steering, 1 esc, 2 fans and 1 AMB.

But make sure this is not a ROAR (or related) event or check your country's rule book....motor can only use 1 fan no bigger then 30mm or no more then 2 fans for the entire car. (I think that is the rule)