Pril Motors - Performance Electric Motorcycles

Racing in the TTXGP

Pril Motors was started as a weekend hobby to convert an old Kawasaki Ninja to electric power in early 2009. The bike, dubbed XR-1 was fitted with six lead acid car batteries and mostly off the shelf components to create a cheap commuter bike for about $4000. After hearing that the TTXGP was coming to the local track at Infineon Raceway, the bike was quickly upgraded to a Li-Ion battery pack to shed about 100 pounds and add a bit more capacity. Besides the new battery pack the bike remained largely unchanged leading up to the race, being the only one at the track still sporting street tires, a license plate, and working turn signals!

Two days before the first official TTXGP practice, the bike was taken to Infineon for a track day. A few of the other teams were already there testing their bikes and after a few short laps, the XR-1 was found to have a throttle response issue but luckily Matt from Electric Race Bikes had some of his inventory at the track and gave us a great deal on a new throttle. The variable regenerative braking was also not working as expected and was eventually traced down to a bad connection at the motor controller. The system works by sending current from the motor back into the battery pack when the “clutch” lever is pulled in. The harder you squeeze the lever, the more current is sent back to the pack acting similar to engine braking on a gas bike. When riding around town, the standard brakes become almost obsolete with this system.

Early Friday morning, the weekend of the first US e-grand prix, the bike was brought back to Infineon and set up inside turn 10 at the TTXGP paddock. As the other teams began to roll in and set up it was exciting to see the variety of bikes preparing to race. Most of Friday morning was spent getting the bike ready to pass the technical inspection which included wiring in blinking safety lights, taping up wheel weights and lights, cleaning up exposed wiring and other minor changes. After passing tech and getting out on the track with a 3:00.4 lap time, another problem was discovered with the bike cutting out at speed. The problem was eventually traced back to a faulty motor controller unit. Brian from Thunderstruck Motors was at the race with the Volt team and offered to bring a different type of motor controller the following day to try to fix the problem.

Most of Saturday was spent pulling out the old motor controller and getting the new one mounted. Since the new unit was a from a different company altogether there were some challenges in getting it installed. All of the high voltage cables had to be extended to reach the terminals of the controller and most of the low voltage harness had to be modified as well. Everything was finally buttoned up just in time for the final qualifying round of the day. Despite not having any time to tune the controller, successively faster lap times were turned in for each of the three qualifying laps at 2:53.6, 2.51.0, and 2.49.5. Despite these improvements from Fridays practice, we still qualified 10^th and in an attempt to squeeze some more speed out of the bike for Sundays race, two additional cells were temporarily added to the battery pack to slightly up the voltage.

After a few practice laps on Sunday morning, the guys from Mazanita Micro helped to rapid charge the pack to get it ready for the race. Since the race was scheduled shortly following the practice round, when it was finally time to pull off the tire warmers, the bike was still not fully topped off but there was no going back now. Rider Zoe Rem got a great jump on several riders at the start of the race and continued turning in consistent lap times (2:41-2:42) to climb from 10^th to 6^th place! As some of the other faster bikes had overheating or overcurrent problems and had to pull over to reboot or exit the race, the reliable consistency of the Pril Motors bike helped it finish the race in a respectable position.

Since starting as a one-man-team going into the race we are now growing and looking to build a dedicated race bike for next year with an eye towards commercialization in the future. The Pril Motors team has a strong EV background including members with professional experience at Tesla Motors and XP Vehicles as well as academic experience with the MIT and Stanford electric vehicle teams. We are now looking for sponsorship to help fund our next bike, cover race entry fees and travel expenses. The race has attracted a lot of media attention including TV coverage on Speed Channel articles in the SF Examiner, LA Times, Wired, Motorcycle.com, Autogblog Green and countless other tech and mainstream media outlets. You can contact us at info@prilmotors.com for information about sponsorship/investment/joining the team or updates on our progress.