don't hold me to this but i have put alot more then 6 volts on my rx and i'm sure that the on road guys have put more then 6 volts on there's with 6 cell packs (7.4 volts) and some of the new 1/8 th buggys with brushless systems and 2 lipo packs wired in series. im not sure just how much voltage that a rx will take but a guy told me once that most rx will handle more voltage then you think but it was the amp draw that would hurt it the most. i dont know for sure but it did sound correct to me because i have had to change some fuses that where rated for 250 volts but would only handle an 1/8th of an amp. hope this helps