HMMmmmm.
As was said
"That is why a battery with a low internal resistance is so critical."
low internal resistance. Measured in milliohms, the internal resistance is the gatekeeper that, to a large extent, determines the runtime. The lower the resistance, the less restriction the battery encounters in delivering the needed power spikes. A high mW reading can trigger an early 'low battery' indication on a seemingly good battery because the available energy cannot be delivered in the required manner and remains in the battery.
These might help you.
http://www.popularrc.com/?p=382
http://batteryuniversity.com/partone-22.htm
i was wrong
to a point on how the brake works on a brushles esc............
BASICLY
not going into pulse timing or other detailed information that is not needed.
when you brake 2 coils get a voltage 1 on eatch side of the armature
the harder you brake the higher the voltage..... in turn slows the armature and or holds it in place.
the esc can detect the rotation and will very the voltage to said coils as is needed as you increase or decrease your brake force
upto the esc's Brake amperage .
but still does not offload voltage to the battery.