Yes, you need an external BEC!
 

Having radio, servo, ESC, motor, or any other electronic troubles? Don't have an external BEC installed for your servo? YES, you probably need one! Read over the stickies at the top of the Electronics forum, and read through this thread.

http://www.rccrawler.com/forum/chit-...ernal-bec.html


At this point in time the Castle BEC is the best value and power for strong servo setups. Are you crawling? You need an external BEC!