Thread: Electrathon - A Different Kind of "Hotrod"

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Well, it's finally on its own 3 wheels. Next up... motor mounts!

OK, first step to mounting the motor is to mock it up in position. I am using a Briggs & Stratton Etek motor here (Yes, Briggs & Stratton makes electric motors!). After situating the motor where I wanted, I added two crossmembers in the frame to support it. The rear one had to be contoured slightly on the ends to get it back far enough.

After the crossmembers were welded in place, I next fabricated the bottom mounts from 18 gauge perforated angle. Yes, this lightweight stuff supports the motor just fine; electric motors don't vibrate like gasoline engines, so metal fatigue is not a problem. I cut these pieces so they are mirror images of each other, notched them to fit the crossmembers, and then folded the bottom edges upward at a 90 degree angle. The fold adds strength and also keeps the bottom edge from hanging below the frame. I mocked up the motor in place again with the mounts underneath to assure the fit and mark which holes would be used. While the motor was in place I fabricated a tab for the top mounting hole; it's a piece of 16 gauge steel, drilled, and a 5/16 -18 nut welded to it. Then I elongated 4 pairs of holes where the motor bolts down to allow for chain adjustment (I put a red outline around the elongated holes so they would show for the picture).

I mocked everything up again, this time with bolts in place. I squared everything up with a try-square and measuring tape, and tack-welded the mounts in place. Then I removed the motor and welded everything solid. Finally, I reinstalled the motor and bolted it down.

I would be interested in learning how you decided on that particular motor for this build. I remember that you said that "BAT" used a 1 hp Scott motor in his. How does the Briggs & Stratton motor compare to this and what other choices are available?
I imagine that there is a balance between the power output and energy consumption so that you can maximize speed without draining the battery too quickly. Have there been any studies made on various motors to find out which are the most efficient?

In order to use an electric motor, an electronic motor controller is necessary. Without some type of controller, the motor would either be full-on or off; there could be no intermediate speed, no smooth acceleration, no real control. A mechanical potentiometer big enough to handle the amperage of two Optima batteries in series would be HUGE and heavy. Electronic controllers do the same job, but are substantially smaller and lighter than a mechanical potentiometer. They use a very low power electronic circuit to control the main power circuit. Although controllers can get expensive, the one I am using here is a remanufactured Scott controller that I bought a few years ago for $160.

I located the controller near the motor, but far enough away so if I ever throw a chain it won't be likely to whip the controller. Mounting it was simple; I just fabricated a couple of tabs that match the bolt holes on the controller and welded them to the rear crossmembers.

Where did you get the motor, and about how much does one set you back?

The car is looking good! Ive mentioned this to a few friends, but no takers yet. Im gonna get somebody to make one with me, then we can race each other.

OK,I'll tade Jim,HA Ha,mine for your Etek,actuly we got the old Scott from Jim,he told us it was the trick motor to use only about 4 or 5 years back or more,tell these new Etek came out and some others at much high cost.
As for the Scott,most efficient?no,but the cost was just right $00000 and I would of give 2X that HA HA $0000000000
Our controller is a old golf cart one that Rex [head part of our 3 man team Rolling Thunder] got from some one for free too.
Yet were winning now and then again the big dogs motors

Sure looks good,as this build gets better all the time

[[In order to use an electric motor, an electronic motor controller is necessary. Without some type of controller, the motor would either be full-on or off; there could be no intermediate speed, no smooth acceleration, no real control.]]

The full on or off reminds me of a minibike my Dad made when I was about 10. He used a bare frame and added a 12v starter motor out of a Mustang, converted to belt drive with a 12v car battery on the frame and an on/off switch. It was wicked fast but that thing was dangerous. Either 'on' or 'off' No brakes either, looking back I'm pretty happy I never got hurt on it.

Cool build - I'm enjoying it very much!

Motors are as many and varied as there are people who use them and I am certainly no expert. I originally built my orange car and the silver car (pictured previously) with Scott 1hp motors. The Scott 1hp (also sold under the NPC brand name) is probably the most common motor in use in Electrathon because it is reasonably priced (about $260 new), plentiful, and reliable. Using 24 volts, it puts out 1hp continuous at 2800-3000 rpm. It is capable of up to 3 1/2hp under load. For its size and weight, it's a pretty efficient motor.

Several years ago, Briggs & Stratton bought the rights (from Lemco, I think) to produce the Etek design that has a radial armature. They made a production run of them and they originally sold for about $395. As the supply started to dry up, the price began to escalate and I saw prices as high as $675 at one point. Fortunately, they are being produced again and the price now is in the $469 range. I bought the one I have 4 years ago for $425. At 24 volts the Etek produces 3 1/2hp continuous at 1728 rpm. It is capable of 8hp under load. It is also an efficient motor.

I am using the Etek here because I am overweight for Electrathon (me personally, not the car) and the higher torque of the Etek gets my lard moving without power-spiking the batteries so bad under acceleration. I also have a couple of Scott motors and, although I didn't mention it above, they will fit the motor mounts in this car if I ever want to run one.

The motor that Dana (The Bat) has is an old Scott that was traded to me a few years ago. It was probably 8 or 10 years old then and had dozens of races on it. I gave it to them so they could at least get on the track "until they could get something better". Dana's partner cleaned it and put a new set of brushes in it and they have been soundly thrashing all the competition ever since. Their success is a testament both to the reliability & competitiveness of the Scott motor and to The Bat's car-building extertise.

Horsepower isn't everything, either... The car pictured below holds the world record for distance/speed in a sanctioned Electrathon event. It traveled 58 miles in one hour using a 1hp Lynch motor. Someone correct me if they know, but I think that Lynch L200 motor costs about $1600. For those of us on a budget, that's pretty steep for a motor ($425 just about broke me!). Occasionally, motors can be found in surplus stores and on Ebay for much less than new prices.

I once considered trying to use a starter motor, but I was told that they won't live through this kind of use. Starter motors are built to produce very high torque for short bursts and burn themselves up with constant running. I don't know... I'm still tempted to try it someday...

For every ones prospective;
The super Fancy aero bodied car in photo post #67 is some very cool work indeed,but there record speed for one hr. was done on a super speedway,so it did not need to make turns like we do in most of our races here in Fla.
Turns like we have would drop that cars speed a lot closer to what we are doing,that is if that car can even make turns as sharp as we're running ?.
I think it's a big gain to have nice aero body if av. speed is above 25mph.
OK,no deel then on the Etek,I think we need both bat's,nuts!

Very cool speed car. Reminds me of some of the cars out at Bonneville!
Jim this is a very cool thread. Looking foward to the rest of the mechanicals, wiring and accelleration linkages!

RestoRod - I'm sure some of the folks who have been doing this longer than me have done detailed comparisons. There might be some results online somewhere, but I have never researched it myself. Many Electrathon teams have websites with tons of info. There are links to some of them on the Electrathon America website (www.electrathonamerica.org).

HRD - Motors are available from several places including National Power Chair, EV Parts, KTA Services, Pentad, Robot Marketplace, Cloud Electric, and others. (Just do a search for one of those or go to the Electrathon website for links to some of them) I have done business with most of them and all have given me good service. Prices are all over the spectrum. I bought a brand new Scott (NPC) from National Power Chair a few years ago for $180 on sale. On the high end, the sky is the limit.

Bat - I'll trade motors with you if you make your driver gain a hundred pounds and disconnect one battery. Then I MIGHT have a chance of outrunning him...

Signshop - How did that Mustang starter hold up on your old minibike? Did it ever get really hot? I have a friend who owns a salvage yard; he will give me starters if I want them... How far are you from Berlin Raceway (Marne, MI)? They have some Electrathon races coming up there in just a couple of weeks.

The starter we used on the minibike never seemed to get hot but we never really rode it a long distance. It had no way to control the speed - 50mph on a minibike is spooky so we just rode it in bursts on to accelerate off to coast...

If you're worried about heat you could always duct some air directly in there too.

I'm about an hour from Berlin. It's a nice facility (for a short track of course)

Stovens - Since you mentioned Bonneville, check this out: http://www.speedace.info/electrathon...tober_2007.htm 89+ mph at Bonneville in 2007.

Signshop - Whenever the motor is enclosed, we duct fresh air to it. Notice the scoop on the side of car below; it's a direct vent to the motor... I looked at the Berlin schedule; that race runs on a Friday during the day. I guess it's for people who don't have to work for a living.

Jim cool Bonneville car. Jim I noticed you sit way back at a fairly steep angle. Is it hard to drive for long periods of time like that, and how hot does it get in there?

Running a car at Bonneville would be a blast! Did you look at any of the videos on that site? I liked the in-car video.

The reclined position is actually pretty comfortable once you get in. The cars are fairly tight inside, so they make you feel pretty secure (see pic below). The most important thing is finding a helmet/ headrest combination that supports your head comfortably. Without that, on some of the parking lot courses we run, your head will be lolling around like a bobble-head doll after just a few laps (been there, done that!).

The fully enclosed cars can get pretty hot inside as they have little or no ventilation. Ventilation creates wind resistance, so... One of my kids lost four pounds during a race on a 91 degree day! The open cars may be slightly more comfortable because of fresh air, but open cars require long sleeves, gloves, and full-face helmets. If it's hot out, the driver is going to suffer a little regardless of which kind of car he/ she is driving. But hey, it's only for an hour at a time...