Other Designs

There are other designs of plug-in conversions. Here is a summary:

Replace Factory Traction Battery

Replacing the factory traction battery with a bigger battery is a really bad idea. By replacing it you lose the fail-safe safety systems of the factory battery. These safeties have been developed over many years and millions of cars. You are replacing the proven factory design with one that is unknown and unproven. The replacement battery may have no safety systems. Some replacement battery packs are made with used parts from wrecked cars. Even worse, they use hardware and software that was designed and built by amateurs. There have been car fires with replacement battery packs. Read more:

When you replace the factory traction battery you will lose the 100,000 mile or 150,000 mile warranty that comes with the factory traction battery.

Toyota service departments will not service or repair your car with a replacement battery installed. They don't have documentation for the replacement battery. Documentation is required to keep their mechanics safe. If the mechanic gets hurt while servicing the car, they are liable. Maybe the company who supplied the replacement battery will service the car, but what happens when they go out of business?

Replacing the factory traction battery creates an orphan car no one wants.

With the Plug-In Supply Modular Plug-In Battery System we leave the factory battery in the car and we don't change the factory hardware or software. The add-on battery pack is easy to unplug and remove from the car or move to another car. When our system is off the car is a stock factory car. Our plug-in battery system will restore the performance of a tired factory traction battery.

DC to DC Converter

This type of plug-in conversion gets its name from the DC to DC converter used to raise the voltage of the add-on battery pack to a level that matches the factory battery. The add-on battery pack is typically 48V. There are problems with this design. They are inefficient. The DC to DC converter generates heat that should be discharged out of the car. 30% of the input power can be wasted as heat. DC to DC converters are complex with many points of failure. This makes them unreliable. The typical DC to DC converter system injects up to 14A of current into the electric drivetrain. This is not enough to sustain EV mode operation and results in poor performance. There is a risk of fire with this design and some competitors' products have a built-in fire extinguisher. Some competitors use poor quality cells that soon fail.

The Plug-In Supply design does not use DC to DC converters. We use contactors (large relays) that are safe, efficient, high quality, and give high performance.

Some Companies that Sold Plug-In Conversions

Enginer. DC to DC converter type. The original Enginer company went out of business in the USA in October 2012. Posts on the web talk about the parties taking legal action against each other. Now back in business? Out of business again? We don't know.

Hymotion. DC to DC converter type. Hymotion went out of business in the first quarter of 2012. They were owned by A123, which filed for bankruptcy around June 2012.

Plug In Conversions. Factory traction battery replacement type. Out of business. They ceased operations some time after a fire in a customer's car destroyed the car and burnt the house.

Plug In Solutions. Copy of Plug-In Supply design. Out of business. We had the unpleasant experience of working with Plug In Solutions from November 2009 through mid-April 2010. After we terminated the relationship they continued to sell an unsafe copy of our 10 KW Prius system, until they were sued by a customer.

Etreks. Out of business.

Hybrids Plus. Out of business.