Electric KillaCycle Sets New World Speed Record

© KillaMotorcycle. The KillaCycle, the world's electric motorcycle, and the official world record holder in the ¼ mile drag, broke the world record again using its lithium-ion batteries. The official record for any electric vehicle worldwide in the ¼ mile is set now at an elapsed time of 8.16 seconds. Weighing just over 165 pounds, the A123Systems battery pack delivers over 350 horse power to the motorcycle drivetrain and holds 7.5 kWh of energy. The KillaCycle set the record at the All Harley Drag Racing Association (AHDRA) event at the Firebird Speedway in Chandler, Arizona on March 31, 2007.

KillaCycle put in another 110 of the most powerful Li-Ion cells in the world to make a total of 990 A123 Systems M1 cells in the bike. This pushed the power output to over 350 HP. They are now able to draw 1575 amps from the 375 volt, 7.5 kW-hr battery pack. There are just 161 lbs of cells in this pack. KillaCycle call the A123 Systems battery pack "Mister Fusion" because it acts like a bottomless pit of power and energy on the track. They could make 7 or 8 runs without recharging if we wanted. It only takes a few minutes to recharge the pack between runs, so we top it off every time. They only use about 700 w-hrs (about $0.10) of electricity for each round. This includes the burn-out and the more than 2 mile round trip back to the pits!

Without these powerful A123 Systems batteries, they would have no hope of setting new world records.

© KillaMotorcycle. Another change Killa made was to install a series/parallel contactor. The Zilla Controller has the ability to operate a serie/parallel motor contactor automatically. The motors are inititally configured in series. Thus, the full contoller output current travels through both motors. This gives maximum starting torque. As the motors spin up, the voltage across each of them increases. When that voltage matches the battery voltage, the current will decrease as motor rpm continues to increase. The Zilla will then switch the motors into parallel connection. This will double to voltage available to each motor, but will divide the current. The motors can turn much faster, but with half the torque. It result is just like shifting a transmission from low to high.

© KillaMotorcycle. They could not get the contactor to shift automatically during the two runs we had on Friday test and tune session. The 60 ft times were fantastic, (1.169 seconds) but we were not getting the top-end performance we needed. We re-wired the launch button to be a manual shift button and this proved to work quite well for the rest of the weekend. We plan to upgrade the Zilla firmware and we believe this will solve the auto-shift problem.

Another improvement they made was to build in Kapton heaters into the battery pack. We used these to bring the pack up to optimum temperature, (75 Celsius) and maintain it there for maximum power output. The A123 Systems cells are unique in that you can bring them to very high temperatures without damage. (They age a bit more quickly at high temperature, but that is it.)

(Via KillaMotorcycles)