how to reach my speed goals?

[nickydlax]

Hey guys im brand new, I need some help figuring out some rough ideas
My goals are to have an electric kart that can get up to 50-55 mph at the most. Acceleration would be awesome too (anything more than a standard car) but id like to take this to work every day, it's not too long of a drive.*Anyways. Would a 72v motor get the job done? If I use a 72v, what should the gearing be? Im thinking about using motorcycle wheels fyi. Thanks in advance!

 

[dcastillo]

Can you show some pics/drawing of what your thinking of building? All we have so far is an electric cart with motor cycle wheels....

And motor voltage is much less important then motor wattage...
You will need a pretty big motor to go those speeds.. even high speed golfcart motors that are 3-4kW and cost $500 only push the cart about 25mph or so...

-Danny

 

[nickydlax]

Well I don't have any drawings but im going to try to keep it as smal as possible. How much wattage should I be looking for then?

 

[nickydlax]

What if I sacrifice acceleration for top speed?

 

[dcastillo]

Im curious how you are going to make a small cart with motorcycle tires...

are we talking only 3 wheels or 4?

Im not an expert, you could probably do it with something like this beast
http://www.cloudelectric.com/Motor-ME0709-MotEnergy-p/mo-me0709.htm

or to save a bit maybe this guy
http://www.cloudelectric.com/product-p/mo-me0909.htm
-Danny

 

[nickydlax]

4 wheels, mayhe some custum hubs, idk yet. Yeah something like the first

 

[Poboy kartman]

Welcome to the forum and please fill out your profile so we know where you are from. .......

 

[itsid]

Hey guys im brand new, I need some help figuring out some rough ideas
My goals are to have an electric kart that can get up to 50-55 mph at the most. Acceleration would be awesome too (anything more than a standard car) but id like to take this to work every day, it's not too long of a drive.*Anyways. Would a 72v motor get the job done? If I use a 72v, what should the gearing be? Im thinking about using motorcycle wheels fyi. Thanks in advance!

well as long as it's blue...

honestly.. voltage is almost as useful as an information as the color;
you need wattage (and it doesn't matter if it's high volts on low amps or high amps on low volts)

55mph is about ~25m/s...

and that will be extremely hard to reach.

to reach speeds like that you'll have to provide roughly 7-8kW
for a lightweight kart (150 kg incl batteries and driver).
Pm = m * g * Cr * v + 0.5 * Da * Cw * A * v³
150 * 9.81 * 0.02 *25 + 0.5 *1.2 * 0.7 * 1 * 25³ = ~7300 Watt
And that's the point.. weight..
to have enough driving time with a motor that powerfull you have to carry lots of batteries..
and I mean really a lot of batteries.
and that means a lot of weight;
and that in turn requires an even bigger motor I'm afraid.. maybe closer to 8kW!

but you can be sure you'll have an awesome acceleration with a motor that big,
so no need to care about that too much

best you read my thread about motors


'sid

 

[nickydlax]

wow your thread is huge lol looks pretty informational, I just heard from another forum that maybe 62v with 1000A should do it? Ill start to look over your thread now

 

[itsid]

wow your thread is huge lol looks pretty informational, I just heard from another forum that maybe 62v with 1000A should do it? Ill start to look over your thread now

LOOOOL

62V and 1000Amps would be 62000 Watts or 83 HP...

of course, with 83 electric horses you can surely push even a heavy kart to 55mph (and beyond!)

So whoever gave you that number must be either really stupid, or wanted to get rid of you really fast

'sid

 

[nickydlax]

I meant 72, lol okay soooo 72v, 100amps? Lol with a 1000a controller?

Golden motors has some 48-72v 3-7.5 kw

 

[itsid]

1000 Amp controller...
....
............
you're on your own; good luck

'sid

 

[firemanjim]

1000 Amp controller...
....
............
you're on your own; good luck

'sid

I'm gonna play nice.... Look, 'Sid is probably (he is ) the most knowledgeable person on this forum, about this subject. (dam smart,them germans) if he took the time to write up a book (lol) for the forum members to wrap their brains around, it MUST contain the most valuable of valuables...... INFORMATION! The guy did his pre-k thesis on the evolution of home and industrial lighting. It was a 900 Page novel, winning him a pulitzer prize...... (ha he wishes, lol)
Point is, if sid put it down, you need to pick it up..... The first 3 words of our forum name..... Do It Yourself...... Go read that thread.... Get a better understanding of how all the works and relates to one another...... THEN ask the "Earl of Electric" ,(sid) , for some expert tutelage......