Brammo Empulse Owner's Manual page 26

Riding the Empulse
Unlike a gas powered bike where you select a gear to keep the
engine speed as low as possible for the terrain, the optimum motor
speed for the Empulse is between 4000 and 6000 RPM regardless of
the gear you are in or the current road speed.
If you try to "lug" the bike in a tall gear and apply heavy throttle, it
puts a very heavy strain on the batteries which will greatly reduce
the operating range of the Empulse.
As you accelerate, if the motor speed exceeds 6500 RPM the green
LEDs above the LCD will progressively light up as an indicator that it
is recommended to shift up to the next gear. At 7000 RPM, all four
LEDs will be lighted.
24
Your Empulse has a regenerative braking system installed. Similar to
engine braking on a gas powered bike, whenever the Empulse is
moving and the throttle is not applied, regenerative braking slows
the bike and feeds energy back to the high voltage battery.
By anticipating your stops and simply releasing the throttle to slow
down, you can take advantage of the energy gained from
regenerative braking to extend the operating range of the Empulse.
The amount of regenerative braking applied when you release the
throttle will vary depending on the mode the Empulse is operating
in.
Regenerative braking does not replace the need to use the lever or
foot operated brakes to stop the Empulse. Only allow regenerative
braking to slow the Empulse when it is safe to do so.
WARNING
Basic Operation and Riding