Police Motorcycles Go Green
Tom Lombardo posted on September 28, 2014 |

In many California towns, the men and women in blue are going green … with zero emission motorcycles. Zero Motorcycles, a company that originated in a Santa Cruz garage, has built a line of high-performance electric motorcycles that not only rival their gasoline counterparts, but beat them in most categories. Law enforcement agencies are slowly taking notice and adding these powerful bikes to their fleets.


Electric motorcycles have several advantages over gasoline powered bikes. Zero’s police motorcycles use permanent magnet brushless AC motors. Variable frequency AC motors are extremely efficient. DC power from the battery feeds a three-phase inverter that’s similar to an inverter used in photovoltaic systems. In a variable speed motor drive, the inverter’s output frequency can vary, which changes the motor’s speed. Unlike internal combustion engines which only run well within a narrow range of RPMs, electric motors run efficiently at a wide range of speeds, so they don’t require a transmission or a clutch. This reduces weight, cost, and complexity, and makes the bike easier to drive. Zero’s motor produces up to 54 hp and can propel the vehicle to peak speeds of 95 mph (153 km/hr) and sustained speeds of 80 mph (129 km/hr).

Batteries and Range

The Zero SP police bike has an 11.4 kWh Li-ion battery bank; the optional “Power Tank” provides an extra 2.8 kWh, giving this electric vehicle a range of up to 164 miles (264 km) in the city, or 104 miles (167 km) on the highway. A standard 120VAC charger will fully charge the battery bank in about ten hours. An optional quick charger cuts that time in half, and a special CHAdeMO adapter allows the bike to charge in 1.5 hours. (CHAdeMO is a growing standard for electric vehicle fast chargers. At the time of this writing, there are over 700 CHAdeMO stations in the United States, and more than 4000 worldwide.) The motor’s controller also handles regenerative braking, allowing the bike’s batteries to recharge every time the brakes are applied. The batteries have an expected range of 370,000 miles (595,000 km). The “expected life” of a rechargeable battery refers to when it can only be charged to 80% of its nominal level. Many used EV batteries are finding a second life in the home photovoltaic market.

Fuel Economy

As governments (and nearly everyone else) are on a tight budget, they need to do more with less. Electric vehicles do their share by offering an extremely low cost per mile. These bikes get 443 MPGe (miles per gallon equivalent) in the city and 196 MPGe on the highway (0.53 and 1.20 L/100km, respectively). That averages out to about one dollar in electricity for 200 miles (321 km) of range. And the simplicity of the bike itself makes it almost zero maintenance, reducing the overall cost of operation even more.

The Clovis Police Department in the San Joaquin Valley recently purchased five Zero bikes for $95,000. Other municipalities, such as the Scotts Valley Police Department, have adopted them too. Here’s what one officer thinks about his new ride:

Electric vehicles are clean, reliable, and inexpensive, and they can be “fueled” with fully renewable energy. Range is still an issue for long distance driving, but for fleet vehicles that stay local and return to a home base every night, it’s not a problem. As quick charging standards like CHAdeMO evolve and battery technology improves, charging an EV on a long drive will be almost as convenient as filling up the gas tank. To that I say, “Road trip!”

Image and video courtesy of Zero Motorcycles

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