Hi there. Ive a few questions about 7.2v Fet Servos
The have a 4th wire that connects to the batt as it wont run on 6v
What happens when the batt volt drops??
are these servos only really for Gas cars with separate rx batt?? rather than 1/10 elec ??

Seems to me they are more suited for electrics, or at least they were. A traditional nitro receiver pack would be about the same voltage as an electric BEC, these were designed to take advantage of the higher voltage of an electrics main battery.

I never noticed a problem with steering as the pack died out, I had steering as long as I had any significant motor power left.