Question about Mamba Monster ESC set-up?????

[THE H.P FREAK]

HI!... O.k I've been running the Mamba Monster ESC/MOTOR combo for years in a bunch of my 1/8TH scale cars/trucks. I've always ran two 7.4 volt lipo's together to get the 14.8 volts. Now I bought a single 18.5 volt lipo due to I did a electric conversion on my "T' Maxx and there was limited room. It works fine. I have the Mamba ESC set on Auto lipo detect. It beeps 5 times and then it's little jingle and its ready to go. It beeps 4 times and its little jingle on the dual 7.4's. Now I just bought two 14.8 volt lipos. Both are fully charged and balanced. Not over charged or undercharged. I double checked with a volt meter. Now my problem is when I connect either 14.8 volt lipo and turn the ESC on it beep 4 times and then no jingle. Steering works fine but got no throttle, reverse or forward. The red light on the ESC stays lit. I've gone through the castle link several times and it still does it. I've tried the 14.8 volt in other RC's I have and they work fine, so its not the batteries.

Any info or help on this would be great. I'm totally stumped. It's probably something stupid that I'm not seeing or doing. lol!

Thanks :

Neal.