I've a highly modified, stretched E-Maxx running 6S.
It HAD a Castle Mamba Monster ESC and with the original lower spec 3S batteries, it was fine.
The batteries finally started getting 'fluffy' so I bought a pair of 3S 5Ah 65/130C Turnigy nanotech batteries.
The ESC started cutting power - too much.
I've now fitted a Castle Mamba XL2 and WOW!! This is ballistic - I'm calling it Mental Maxx!!
How does this relate to you?
Basically, it's a good question originally. It depends what your ESC, and motor can take I suppose.
With higher spec batteries, you'll soon expose the ESC, and/or motor.
It might not have a problem with good batteries.
I'd DEFINITELY recommend the Turnigy nanotech batteries - fantastic power!!
Is the system Castle anyway, on the Flux? Can you use a Castle link to check the programming? Perhaps the punch and timing can be limited?
Al.