TrippyJoey

iTrader: (1)

I'm a 3rd year engineering student and I was just asked last week by the engineering department chairman to join one of the engineering department's projects which is their fuel efficient vehicle program. Currently our first part of the project is converting there gas powered go-kart into an electric motor powered go-kart (which I have no experience in the electric motor powered department) after doing some chassis and suspension modifications which I suggested such as adding a real suspension to the chassis instead of just having all four wheels directly bolted to the chassis with no suspension travel whatsoever. Our next project after some of my suggestions might be building from scratch a small vehicle powered by a LS series aluminum motor which we'll modify to run more efficiently, as well as a well designed chassis and body with a low frontal drag area and drag coefficient to make it as efficient as possible.

My questions are as follows:
1. What is a good TEFC (Totally Enclosed, Fan Cooled) 5hp Capacitor Start motor that we could use that is reliable and not prone to overheating due to the fact that it will be used for prolonged periods int the hot south Texas heat.
2. What are our battery type choices if we want a battery that could efficiently hold a charge strong enough to power a 5HP Capacitor Start motor for extended periods of time.

CJRiojas

iTrader: (1)

I cant really help with the motor cuz i havent done sufficient research on my own. Motor information should be in abundance online. For batteries, you will need a bank(more than one) and they need a seriously high amp/hour rating. I've seen lithium batteris used. that also will require intensive research. I did see some of the ME guys convert a motorcycle to electric. They had a bank of around 20 batteries and completely enclosed off from the driver. an important aspect was they replaced only the engine and battery with the e-motor and batteries and the vehicle weight didnt change. they were also able to run it up to 55mph and hold it for 45 minutes or something like that. Sorry i couldnt help more.

TrippyJoey

iTrader: (1)

No actually thank you, any little advice or information is helpful. Now I think fitting a bank of batteries will be kinda of a problem on our little go-kart, I feel good now for having suggested the chairman extending the chassis.

CJRiojas

iTrader: (1)

I was more shocked you said it had zero suspension. i literally slapped my forehead lol


I also forgot to say the shaft from the motor was able to fit and bolt directly to the transmission with a custom adapter. The adapter was pretty pricey though. Do you have a sponsor? Is this for SAE?

TrippyJoey

iTrader: (1)

I didn't say it had zero suspension just no suspension travel for rebound and compression. The axles are held on by brackets on the chassis unlike your average go kart which has a coil spring and/or a Macpherson strut.
Most Go karts have something like this:

Our Go Kart currently is something like this:

TrippyJoey

iTrader: (1)

Actually we might build a whole new transmission using CNC machined parts from our machine shop, and as I mentioned in our original post this isn't for SAE this if for my universities engineering department', to be specific the department chairman because he will be using it as his personal incampus form of transportation.

CJRiojas

iTrader: (1)

ok, i misunderstood. LOL the chair is a pretty smart dude. Who is gonna pay for the build?

trx250r

I would definitely look into the briggs etek brushless motor. I was in a high school class that used the brushed version in a electric go kart and it worked well and the brushless motor is more efficient. If you ran a custom lithium polymer battery pack at around 48v you could definitely achieve the power you are looking for while still being quite lightweight. Aerodynamics and rolling resistance are key for longer run times.

TrippyJoey

iTrader: (1)

Thanks for the advice I'll check out your suggestion.

The engineering department is paying for it and right now thanks to some multimillion dollar contracts and donations the budget seems that it might be pretty big, which is why we are building two vehicles with two different approaches. The first one will be this electric powered one and the other will be a gas powered vehicle probably built from scratch.

nodrok

I think we need more details. If your project is specifically for efficiency than no suspension would be better. Less side wall in the tires would be better as well, skinnier also. Think of a train for parasitic efficiency. lithium batteries are you best choice because of weight, ion's better for longevity, poly's for power.

Theres just so much to consider, really need more info. but thats something to start.

TrippyJoey

iTrader: (1)

The terrain here at the campus vary and suspension would be helpful comfort wise, remember this is for the Department Chairman the guy who will give permission to have my future engineering classes unblocked ( to take engineering classes in my campus you need department approval for each semester) as well as the person who will sign the checks for my senior design project.
Here is a short list of the type of terrain the go-kart will ride on: smooth vinyl indoors, brick covered sidewalks, asphalt roads, concrete parking lots, dirt trails, grass, mud, and the banks of the local resaca.
Oh and thanks for the advice on the sidewall size and for the info on batteries.

nodrok

I would assume the fuel efficiency part of the program is an important part. depending on where you are in texas lithium batteries dont really like 40 degrees and below. You may consider gel batteries. mimic a powered wheel chair or electric golf cart. you can use a cvt or converter clutch like a snow mobile ( just need to gear it to get in the correct operating speed. When in doubt stick to what works KISS. However if I was being graded on something innovative I would maybe go a different route.

Show us a pic of the actual cart. may be able to come up with more ideas

TrippyJoey

iTrader: (1)

We are in the southernmost tip of Texas, literally just a few hundred feet from Mexico. So our temperatures rarely go under 76F except during winter. This is not for a grade it's just a project that the chairman wanted us to do as an example of his renewable energy and ecofriendly policies, to use for demonstration purposes at high schools, and he doesnt' want to walk 1/2 a mile from his office to the classes and back under the hot texas sun. I'll try to post pics of the go-kart soon.

trx250r

A gearbox, cvt, or even a slipper clutch would completely unnecessary for your application. A gear reduced direct drive will be plenty to propel 400lbs of man and machine to 35+mph fairly quick. A gates poly chain is a good way to go.

chuntington101

Have a look at this guys website. He and his company are trying to build a electric trackday car.

http://www.dpcars.net/

Its the 4th pic down on the left hand side.

Chris.