Powering cooling fans

[kamocat]

We have a couple motors on our robot that will be stalled, though not at full power.
Nevertheless, it seemed a good idea to put a fan on them, as their internal fans do not work when the shaft is stopped.

So, we have 18 gauge wire coming out of the Power Distribution board with a 20A breaker.
Do we need to use a Spike relay, or can these be wired without that?
Can they be on the same circuit?

How would you recommend going from 18 gauge wire to the 26 gauge integral to the fan?

(This is where I would really appreciate being able to use the solenoid breakout, but I know that is against the rules)