I was looking at the specs again I think my 5s A123 pack will be okay...it sits fully charged around 16.6, and the mamba is rated for 12 nimh which at top charge will sit at around 1.4v a cell doing a max of 16.8 and the hardware is rated just over that too. But like I said I'm still waiting for the ESC for the real test and will post the results...I am supposed to get the MM tomorrow.
IT WORKS! I got everything set up and sure enough 5s A123 is working great. I have to do some more specific test but it was starting up with the input all the way up at 17.5v. Thanks guys for the help. Now I got to find some diff replacements because I burned mine up in the first 40 minutes of running.