i run analog servos in my crawler (hitec 985 front steering, 645 rear steer and old 605 for dig) with a castle bec set at 6.7 volts. my reasoning behind that a nitro car runs a 5s nimh pack, and when fully charged they put out over 7 volts nominal, and i found under load to be around 6.7-6.8 volts. i figure if servos dont cook themselves in nitro stuff, running the slightly higher voltage from the bec is fine. ive been running my crawler like that for several years, never had any issues.