# Add-on EV Drive



## Hugh-Falls (Aug 9, 2010)

Why aren't there more EV add-on projects where EV capability is added to an existing car whether it is IC only or a hybrid? It seems to make sense to simply add an EV drive mode to a fully functioning vehicle. Ideally this add-on should not interfere with normal existing functions and other than the additional weight should be an acceptable way to add EV capability.

Mike Dabrowski's E-wheel ( www.99mpg.com ) was an effort to add an external EV drive to a Honda Insight hybrid. Variations on his battery powered retractable 5th wheel has been tried by others with limited success. Adding a motor at the accessory section of the IC engine has been tried. Electric motor driving a sprocket attached to front wheel drive shafts does have problems. An electric motor grafted along the drive line/shaft of a rear wheel drive vehicle is probably one of the more successful early solutions. There is the obvious wheel motor solution which has unsprung weight and cost/availability problems. Sprocket adapters for belt or chain drive have been suggested with the drawback of continuous belt/chain engagement whether EV mode driving or not.

Several variations not tried (as far as I know) may be useful to consider:
1.) Rubber tired EV drive wheel(s) could be toggled up against rear tire(s) when drive is required rather than against the ground as in the E-wheel.
2.) Caterpillar tractor-like double sided belt drive(s) could be toggled up against sprocket adapter(s) on rear wheel(s) when in EV drive mode.
These suggested drives would mount to the exterior at the rear of the car similar to a trailer hitch adapter and could be quite compact and may possibly fit within the limits of some rear bumper covers or the bumper covers could be extended a bit to form a "bustle" if needed.


----------



## dougingraham (Jul 26, 2011)

It isn't normally considered because it is really really difficult to do properly. What you end up with is just a hybrid which has all the disadvantages of both power systems.

The OEM's spend hundreds of millions of dollars designing their hybrids and what you end up with in most cases is barely more efficient than a similar ICE car and at a considerable additional cost.

On the other side of the coin with good engineering you can add in an electric motor for torque fill and come up with a super car (Porsche 918, McClaren P1, Ferrari LaFerrari) but at a terrible cost.

It is easy and straightforward to convert a car to an EV and the results are usually more than good. My conversion is the second best car I have driven. The best was Jack Rickard's Tesla Model S. Of course the Tesla was more than 5 times more money than what I spent.

It is really all about the weight. The additional weight of the alternate system is a killer.


----------



## Karter2 (Nov 17, 2011)

> ?....Variations on his battery powered retractable 5th wheel has been tried by others with limited success. Adding a motor at the accessory section of the IC engine has been tried. Electric motor driving a sprocket attached to front wheel drive shafts does have problems. .....


... I think you answered your own question as you went.
The wheel hub motor is the " Holy Grail" for this , but as yet there are no practical solutions available.
Really, with the increasing availability of OEM hybrids, and used versions of the same, at bargain prices, it is not really worth the cost and effort to attempt a DIY conversion .


----------



## Hugh-Falls (Aug 9, 2010)

dougingraham and Karter2: Thank you for your thoughtful comments. The issues you raise about the feasibility and economics of an add-on EV mode make sense.

I like my 2003 5 speed Honda Insight hybrid and will drive it until the wheels fall off, however, when I am in heavy slow moving traffic, I keep thinking how nice it would be to have an EV drive mode available to be able to creep along silently and effortlessly without all the shifting. Unfortunately, with the Insight, the IC engine and the electric motor drive are bolted together as a unit. If a clutch could be added to be able to disconnect the IC engine, pure EV mode would be possible. So in my dream, the additional clutch or the add-on EV drive appear to be the two ways to achieve my ideal Insight.

The add-on EV drive appears to be something that could be done in a fairly low tech way. Adding the clutch appears to be a lot more difficult.

There may be other ways yet undreamt of.


----------



## Ampster (Oct 6, 2012)

I don't know if it is available for the Honda Insight but there is a kit by third parties that makes an older Prius behave like a plug in hybrid. 

I did a brief google on "honda insight plug in conversion kit" and found a few things. You may wish to follow some of those.

NOTE:
Subsequent to posting the above I found this thread on this Forum:
http://www.diyelectriccar.com/forums/showthread.php/honda-civic-insight-ima-and-mods-22795.html

Apparently the Insight is a gas driven Hybrid assisted by electric versus an electric driven assisted by gas. That would make my suggestion very difficult


----------

