Brammo, makers of the Enertia commuter bike we tested (CIV, April), has announced that it has broken through "the dual barriers" of electric-motorcycle range and speed with a new model called the Empulse. The company states that this machine has the capability to sustain (not merely to reach) 100 mph and will be offered in three versions.
Brammo learned from customers that range is a number-one concern of electric-bike users, who would also like greater speed capability; a genuine 60-mile range seemed to be the magic number. So, the company will offer three Empulse models with 60-, 80- and 100-mile ranges, corresponding to batteries of 6-, 8- and 10-kwh. The higher speed will enable these machines to handle freeway conditions with assurance.
Originally, Brammo felt it would be unable to fully develop these heightened performance capabilities in prototype form until some time next year, but a conversation with CEO Craig Bramscher revealed that batteries built to Brammo specs have proven possible to produce more cheaply and sooner than anticipated. This will allow the company to offer the new models ahead of schedule.
Quoting from the Brammo press release, "Estimated MSRP for the Empulse trio when deliveries start next year are: Empulse Sixty $9995, Empulse Eighty $11,995, and Empulse One Hundred $13,995. All three models will be eligible for Federal and State tax incentives. For example, the Empulse One Hundred may cost as little as $7000 in certain states after Federal and State incentives."
The power to reach 100 mph is not the challenge; we know that 20-hp 50cc GP bikes used to peak at 120 mph. The issue is to control motor temperature at steady high power, which is necessary to prevent its rising to the 250-300-degrees F that can damage winding insulation. The motor in the Brammo Empulse is liquid-cooled (you can see its radiator just below the steering head), enabling it to deliver high power continuously without overheating. The motor is being built by Parker-Hannifin especially for this application.
Heat in electric motors is generated mainly from the resistance of the wire windings and from magnetic hysteresis loss in the magnetic poles that pull the rotating armature around. Even at 90-percent motor
Empulse One Hun is said to provide 100-mile average range and freeway-capable speed. Another critical element? It doesn't look like a refrigerator.
efficiency, this waste heat accumulates if not removed. One way to deal with it is to program the power supply to reduce power (as disappointing as what happened to Dani Pedrosa when his fuel system went into fuel-conservation mode in a recent MotoGP). Brammo has met the problem head-on with liquid cooling that actively removes waste heat to limit the rise in motor temperature.
As compared with internal combustion, the energy cost of electric vehicles is low. Bramscher gave the example of 15,000 miles of operation for $100.
Motors and controllers for electric vehicles are already very good. It is mainly the rate of progress of battery capability that limits performance. With the Empulse, the people at Brammo are using that progress to their advantage. E3
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