Trik's Electric xB
 

Well guys as I have said before I have a Scion xB, Showcar, which has been a money pit since day 1. The good news is I have made many friends in my travels with it, but it is nothing more than an expense. So now that I cannot afford to show it due to gas prices, I decided to tear it apart and make it an electric vehicle.

Here are the preliminary plans.

-Add a rear axle to the vehicle to which I will attach 2 electric motors
-Transverse mount the ICE and use the crank to power a bank of alternators to keep the battery pack charged.

Yes that is a very rudimentary plan, but no need to bore anyone with specifics yet.

My question however is, when hunting down a suitable rear end, what gear ratio should I be on the look out for? I might as well start on the right foot.

Thanks for the help ...

Oh btw, this will be a long distance, highway speed electric car ..

It's not really an electric car if you still have the engine...:p

You might want to look at the EBox by AC Propulsion to get an idea of conversion details. You can buy a freshly converted Scion Xb for the low, low sum of $55,000. :D

Tom Hanks has invested in AC Propulsion. If I had a lot of money, I would too. Alan Cocconi is brilliant.
http://www.youtube.com/watch?v=Xw7zN...eature=related

Other comments:

* A series hybrid is going to be much tougher to pull off than a pure electric car.

* I'd work out a budget to see what kind of performance is in reach. A conventional car with freeway speeds and range over 30-50 miles will be looking at ~$15-30,000.

* While a Scion XB may make a great show piece, you'll make life easier by choosing a more suitable car. Why work uphill with a rolling brick?

* With battery costs put into the mix, I doubt an electric car is going to be much cheaper than an ICE in the near future...at least not enough to justify the pain of a conversion.

- LostCause

-Yeah, no way in hell

This isn't about easy, its the challenge and the transformation of an already heavily modified vehicle that has no current purpose other than breaking windows with a 5000watt stereo.

You don not want to know what I have invested in this thing ... lol, as I build it though, I learn and that is why I want to challenge myself with this project

You said it, it will make a great show piece and even ecourage a couple of people to think outside the box of ugly electric plain cars.

Now despite some of those challenges, if planned properly this could turn out to be a worthwhile project, for me at least. Also, consider that I have sponsors to help offset costs, if I excite them about being involved in the ECO friendly build of a show car, my costs may be offset even more.

Prior to this this car was driven maybe 1000 miles a year, mostly on and off trailers, that may not change, but having the possibility of cranking down the road on battery power would be pretty cool for me anyhow. I appreciate the comments, in fact I use them as fuel to work harder.

But I still want to know what to look for as far as a gear ratio for a rear end.

If you are going without a transmission i.e. straight on the diff then you want pretty much as high a ratio as possible, most EVers drive in second gear around town and third on the highway so you'd probably need a diff with a ratio similar to a normal diff + 3rd gear. I know forth is usually 1:1 but I haven't heard of anyone using 4th gear and getting any benefit from it. I'm using a single gear on my motorbike and I'm looking at 5 or 6:1, just based on the max rpm of the motor and my max top speed.

Is there a centrifical clutch setup I could look into? When I was building my mini choppers we used them in conjunction with the briggs and strat motors and achieved speeds well over 90mph.

I may have to look into that option ....

A semi serious search for a rear axle with the same bolt pattern turned up the late 80's, early 90's Isuzu Pick up as having a 4 x 100 bolt pattern. Can anyone confirm that for me and perhaps enlighten me on the rear end gear ration of that vehicle?

One other consideration you might want to take is that a serial hybrid will probably get the same mileage as a conventional car. You are essentially replacing a mechanical transmission with an equally inefficient electric one.

The only way you'll get ahead is if you downsize your engine and run it constantly at its max BSFC. To do so, you'll need a battery or ultracapacitor bank to soak up the fluctuations in the driving cycle.

Rather than run a bank of alternators, you'll gain efficiency by driving a single motor directly. You'll also gain efficiency by running a single motor on the rear differential rather than two. A direct attachment to an OEM differential probably won't work as most advanced motors will require a reduction of 6:1 (~12000rpm redline).

A centrifugal clutch is meaningless on a motor because it stops spinning at a stop...unless you're running a funky, old constant-speed AC motor.

I hope I don't sound like I'm knocking down your idea. I'm just trying to make sure you start walking in the right direction. :o

- LostCause

Not at all, my admitted expertise is with a welder and sawzall not battery packs and controllers ...

As I continue reading I have learned about AC and DC motors. To put it simply, are we looking at another VHS/Beta, HD/Blu ray, revolution or will both types of motors continue to exist and improve in harmony?

Definitely not a Beta/VHS issue. Both types of motors will co-exist forever. AC is generally more expensive to implement, but offers other benefits (usually higher efficiency, easier to regen).

I don't want to rain on the parade but Lostcause has raised some good points. Without a very high budget, a highway capable series hybrid will be difficult to pull off, and will not be much more efficient than the gas car.