Energy & Environment

Article Tools

Image Gallery

Print

E-mail

Comments

RSS

FOR FUN, FITNESS & FUNCTION

One of the more efficient and inexpensive hybrid EV designs blends human power and electric propulsion. Adding a small motor and battery pack to a bicycle lends the energy of a second person without the weight penalty, and works well for cycling over level terrain, climbing grades and reaching higher vehicle speeds than pedal-only operation provides.

Electric-assist bicycles use four methods to integrate the motor with the vehicle's chain-works: tire drive, chain drive, torque-sensing and hub motor.

The ZAP system is an add-on, tiredrive system that mounts the motor to the front or rear bicycle forks. A thumb switch near the right handlebar engages the motor to press a roller on the motor shaft, which helps spin the tire. This design wears the outside of the tire rather quickly, and necessitates more frequent tire replacement. A sealed 12-volt, 15-amp-hour battery rests in a canvas boot under the top rail. Tiredrive systems include the Zeta II (front drive, $149), single-motor ($359) and dual-motor ($449). The motor kit is integrated in the Powerbike ($599) [(800) 251-4555; www.zapworld.com ].

The Currie motor uses a separate chain drive and sprocket mounted at the rear of the bicycle to power the rear wheel. Currie offers the E-Police bike, E-Tryke and E-Cruiser, E-folder and a U.S. ProDrive motor system for adapting an existing bicycle ($450). The bikes will travel speeds of 13 to 20 mph (depending on model), with a 12- to 15-mile range with pedal-assist [(800) 268-8596; www.currietech.com ].

The Panasonic E-hybrid bike powers the same chain used by the pedals to drive the rear wheel, using a torque-sensing feature to amplify the pedal input. The 12volt, 4.5-amp-hour battery pack will take a rider 20 miles on a single charge. A push-button control box within range of a rider's thumb lets the operator select both the electrics (on or off) and degree of electric assistance (high or low). The box also contains a three-LED display of the battery's state of charge during operation. The 4.5 pound battery is easily removed for charging, and the lightweight charger has both a quick (two-hour) and overnight (eight-hour) charging rate. The torque-sensing feature demands pedal input to work, so there's simply no way to drain the battery pack too quickly. The Panasonic provides intuitive and smooth operation, predictable range and enough of a workout to truly qualify as an electric assist bicycle. It sells for $1,395.

RSS | Comments | E-mail | Print