How to Convert Your Hybrid to a Plug In

• Posted on Autos.com Editor
• in Car Buying
• on October 7, 2013

Many people who own a hybrid car like a Toyota Prius will be happy to hear that they have the option of making their car a hybrid plug in. Why convert a hybrid to a plug-in? It can perform strictly as an electric car running on charged batteries for a range of up to 60 miles. Then when the batteries are depleted, it runs like a regular hybrid—electric up to a certain speed then gasoline powered beyond that speed. This can make the car dramatically fuel efficient. You could potentially go for a whole month or longer without stopping at a gas station as long as you keep the car plugged into an electrical outlet overnight. The car can also lower carbon dioxide emissions by about one half.

There are a number of aftermarket companies that manufacture hybrid-plug-in conversion kits. They include:

• Hybrids Plus, Boulder, Colorado – Ford Escape and Toyota Prius (http://www.hybrids-plus.com)
• Plug-In Conversions Corporation, San Diego, California – Toyota Prius (http://www.pluginconversions.com)
• Amberjac Systems, Great Britain – Toyota Prius (http://www.amberjacprojects.com)
• Green Car Company, Kirkland, Washington – Toyota Prius (http://www.thegreencarco.com)
• OEMTEK, Milpitas, California – Toyota Prius and Ford Escape (http://www.oemtek.com)
• Luscious Garage, San Francisco, California – Toyota Prius (http://www.lusciousgarage.com)
• Plug In Supply, Petaluma, California – Toyota Prius (http://www.pluginsupply.com)
• Hymotion, Watertown, Massachusetts – Toyota Prius (http://www.a123systems.com/hymotion)

If you purchase a bare bones kit and do the conversion yourself, the kit could cost as low as $4,000. However, if you don’t have any do-it-yourself skills, and you want to be certain that the best components are involved; it could cost as much as $35,000 for a kit and installation. 

The basic installation of the A123 System Conversion Kit is described at the Hymotion website. It is a four step process:

1. A hole is drilled into the bumper of the car and a receptacle is installed with a waterproof cap. This is where the cord plugs in to the car.
2. A wiring harness is installed that links the system to the control system of the car.
3. The spare tire is removed from the trunk and a module containing the battery pack is placed in the open space.
4. The module is mounted and connected to the wiring previously laid out and the spare tire is re-placed into the trunk. 

Most kits use lithium ion batteries. But there are some that use nickel metal hydride or lead acid batteries.

Commonly, the kits feature 3 modes of operation:

1. The standard mode when the plug in conversion is not engaged.
2. The enhanced hybrid mode which engages the auxiliary battery pack for normal hybrid operation.
3. Electric vehicle mode during which the car is running purely on the conversion kit system. 

Most kits are designed to convert the Toyota Prius because of its popularity and because the design of the car mates well with a plug in conversion kit.