My boss asked me to build a golf cart that can "smoke tires"

auraslip

auraslip

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I have at my disposal a lot of 8v 250ah lead gel batteries, 7kw brushed motors, and one stretch golf cart frame with plenty of room for batteries (twice as much as a standard cart)

My boss wants to build a marketing car. One we can take to shows and hold the brake and gas down and make some smoke.

My concerns are finding a controller that can handle it. Hoping the motor and mechanical parts won't tear themselves apart. Also i need to figure out a way to calculate how much power it will take to smoke the tires.

This is not a golf course motor. These carts are stock pretty quick and top st 25mph. Unfortunately i dont have any info on the motor outside of the sticker. Im hoping i can get more info like saturation point from my tech guy at the factory. Im hoping it's like overvilting a hub and i can get 3x or 4x the rated power for short bursts and utilize the temp sensor in the motor. Stock they use 6 8v batteries. Frame has room for probably 8 extra batteries. 112v!

Anyways, this build is going to be done. And knowing my bosses they'll spare few expenses. Custom paint, custom upholestery, blingy wheels, lights, stereo. And what ever tech i want. Within reason of course.
 
Best place for what you're after is the DIY Electric Car forum, using the series-wound brushed forklift motors and controllers (or if you don't care about limiting the current, you can just use contactors).

You might be able to do it with the permanent-magnet brushed motors golfcarts typically come with, for short bursts, but doing it repeatedly might require forced air cooling thru the motor so you don't cook the commutator, at the least.

I think that if you are wanting to smoke the tires you probably want the batteries and all other weight all up front, so that there's as little as possible holding down the back end, to take as little torque as possible to break the tires free from the pavement surface.
 
Yep.

On the plus side, high powered controllers for brushed motors are a lot more common and cheap compared to brushless ones.
 
The hayabusa is a popular swap. They're like 200hp, and rather monsterous. What are you planning on shooting for? I would think even 80hp geared for 40- 50mph tops should tear pretty good. Something like 80kw peak, 40kw continuous?

I'd think a single powerplant thru differential, keeping RWD, and possibly adding heavier LSD if upgrading drivetrain to take the abuse? Or go cheap and just weld the diff to posi, for even more fun :D

Otherwise if using the mentioned 7kw (peak?) motors - two independant for the rear, that would be cool too and shred nice if you keep gearing down.
http://www.ebay.com/itm/12-NISSAN-LEAF-ENGINE-EM61-ELECTRIC-TRACTION-MOTOR-9197677-/331860840102?hash=item4d44728ea6:g:9eQAAOSwGeBXP1kX&vxp=mtr
I vote for the 80kw tho. Maybe a small wrecked EV motor and controller ran conservatively could be a good route, but maybe it'd be too much weight?
 
Yeah but im not a member of the diy car forum and they arent as sharp as yall.

We cant move all the batteries to the front and get massive voltage with out rearranging the frame. If we go that route we might as well switch to lipo.

We aint doing gas.
With the leaf setup what sort of voltage would we need to get the results we want? Could we attain that with the batteries we are working with?

Today im going by the shop to snap some pics for this thread. Im also going to be trying to find some math i can use to figure out how much power i need and how much power i can get out our stock motors.

This is going to be a bad ass build. We are going to have our fab guy do five point harness and roll cage.
 
Im sure the golf cart will have a DC/DC converter to provide about 10A of 12V for accessories. If yes, go to the junk yard and get window washer sprayers from a car, and mount them so that they spray a liquid just in front of the driven tires.
 
I made a golf cart that does solid burn outs on dry asphalt by doing nothing more than swapping it's sad SLA for lithium and swapping it's 200A motor controller for a 650A.

It still works as far as I know too, gets used daily on a friend's farm.
 
Be careful, torque from electric motors can easily twist shafts and break stuff. Control used to be done with relays, power resistors, and contactors to step through different voltages. If it doesn't need fine control, these would work.
 
liveforphysics said:
I made a golf cart that does solid burn outs on dry asphalt by doing nothing more than swapping it's sad SLA for lithium and swapping it's 200A motor controller for a 650A.
Click to expand...

"Job jobbed" :)
 
Im sure the golf cart will have a DC/DC converter to provide about 10A of 12V for accessories. If yes, go to the junk yard and get window washer sprayers from a car, and mount them so that they spray a liquid just in front of the driven tires.
Click to expand...

A+ IDEA

I made a golf cart that does solid burn outs on dry asphalt by doing nothing more than swapping it's sad SLA for lithium and swapping it's 200A motor controller for a 650A.
Click to expand...

Problem with ditching lead is that testing and making a pack with lipo is time consuming, and unsellable to anyone but a nerd like us. Lead is cave man proof. That being said I'll run the thought by my boss.

Be careful, torque from electric motors can easily twist shafts and break stuff.
Click to expand...

:twisted: Well at least we can find the limits of our rear ends :twisted:

Here is some pictures of what I'm working with.

7V8MoLYl.jpg


Frame we are going to use.

xJ6UStSl.jpg


Rear end we are going to use. Notice the motor has a active air cooling.

nbX1XFpl.jpg


Here is a jeep we are restoring. Notice the full body kevlar we had our kevlar shop do. Expensive stuff. I post this so you get an idea of the budget my bosses are willing to throw at crazy stuff.
 
auraslip said:
http://i.imgur.com/7V8MoLYl.jpg
Frame we are going to use.
Click to expand...
Stick as many of those batters as you can in the nose in front of the wheels, and it'll leverage up the back wheels a bit, making wheelspin easier. Put as many more of them as possible as close to the front wheels as possible, and nothing at all at or behind the rear wheels, and it'sll help there, too.

of course, this reduces the traction at rear wheels so it means that it won't have take-off torque like it would with the stuff right on the rear axle line, but it *will* help wiht smoking the tires. ;)

http://i.imgur.com/xJ6UStSl.jpg
Rear end we are going to use. Notice the motor has a active air cooling.
Click to expand...
Too bad you can't put the motor vertically into that diff; it'd take out one potential weak link of the right angle gearbox there.

But the active cooling will definitely be useful for your purposes...as long as you realize that if it already had active cooling it might mean it's continous rated power is not as high as might be if it were designed to run without that under normal conditions.

i can't tell, but if it's a regular separate dc brushe dmotor on the fan for it, you can also set it up so that whenever you press the accelerator hard and/or current ijncreases beyond some specific limit, or temepratures get past osme limit, it overvolts the fan motor to get more air thru there. Just don't exceed it's max rpm so the fan doesn't disintegrate or break the commutator on the fan mootr. ;)



I post this so you get an idea of the budget my bosses are willing to throw at crazy stuff.
Click to expand...
Now that's something I wish i could get for some of my projects. :lol:
 
I'm going to move as many batteries to the front seat. Maybe see about fitting some in the nose as well.

The plan as of now is this Curtis controller: http://curtisinstruments.com/?fuseaction=Products.home#/product/65

It uses the same wiring harness as the curtis controller on our cars now.

Except it does 80v 600a instead of ours which only do 48v 400a.

I need to find out what caps it has in it. If 80v is the hard limit, then i'm stuck at 64v. If it's a soft limit, I can move up to 72v nominal. Even at 64v I'm doubling the peak power up to 50HP though.
 
Also you could either practice doing this, or build a mechanical setup to first

let the vehicle roll just a hair forward first as you hit the accleerator,

brake with just rear wheels to break them loose

then brake with just front wheels to hold in place for wheelspin.

If I time it right, I've found that this can break loose the rear wheels on SB cCruiser for turns that I might otherwise tip a bit on, though i have no mechanical brakes on the rear just electric so it doesn't work from a stop, only at speed for me. If Ihad mechanicals too it'd work at a stop, possibly, if i took the trunk and stuff off the back to reduce weight over axles.
 
Curtis said HVC is 104v. Wondering what config ill do with my 8v gel lead. Im think 10 of them for "80v." Its going to be a pain to find a charger for it. I cant have a diy solution with multiple chargers since we plan on selling it eventually.

One worry about the controller is that it doesnt have a speed sensor. I guess thats ok since i planned on using a cycle analyst.

Anyways had a busy week and didnt get anything done on the dragster. We delivered a car to these dudeperfect guys today and it already has 100k likes on their instagram and we got 15 inquires. Looks like ill be building this on the weekends.

 
I would go a HPEV package they build specific high end golf cart motors that come with AC controller and all programable.

www.evwest.com

Are a supplier I use CALB CAM 72Ah lithium cellns 24 of them weight less than 26 Kg and about the size of 2 slabs of beer will give 580 Amps.

Cheers Kiwi
 
Custom hood scoops. Not my design or work but very cool.

I plan to tie orange leds to the throttle and make them blink in sequence inside the scoops. I need to figure the easiest way to do that. Oh well was looking for an excuse to learn arduino.
 

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Do you mean you want them to come on in order, so the more throttle the more are lit? If so, an LM3916 dot/bar display driver / VU meter chip would do that easily, and is already got everything built in except for two resistors used on Vref pin to scale the input voltage to give you full scale output for full throttle input.

It handles 10 LEDs (if the LEDs are identical enough, you could parallel the ones between the two scoops and use just one chip to drive both, or put the pairs in series if the voltage is high enough).

IT also has a dot mode so only one LED is lit at a time.

Has at least two variations, for linear or VU use,
http://www.ti.com/lit/ds/symlink/lm3916.pdf


I used to use these things in my sci-fi props, inputs driven by microphones, magnetic loop sensors, thermal sensors, or most commonly just 555 timers or inverter-timers driving capacitors to give various ramps. Real easy to use. :)
 
9ef29648644c6c848736fd4884b77842resNet11_na.jpgGot the contactor and controller installed today. Still need to wire it up. Which will be fun im sure.

Contactor is big. 10 lbs?

Just found out car show is the 20th. I dont think ill have time to do the blinking leds in the hood. I dont think ill have much free time till then.
 
Everything is here. I just gotta slap it together by saturday for a Mopar show in dallas. Stop by if your in dfw. Its at gas monkey.

Elliots dropped off some fay ass welding cable. Biggest ive ever worked with. 1/0 gauge
 
auraslip said:
Everything is here. I just gotta slap it together by saturday for a Mopar show in dallas. Stop by if your in dfw. Its at gas monkey.

Elliots dropped off some fay ass welding cable. Biggest ive ever worked with. 1/0 gauge
Click to expand...

be careful of welding cable some of the cheap stuff is only single insulated not double insulated.

Good luck

Cheers Kiwi
 
20160817_175411.jpg

Did the dash today. All I'm doing for this weekend is a low/high speed switch, FnR, power, and run/tow. In the future I'll install our stereo system, our street legal lighting system, and whatever cool features we want.

7865.jpg

Wired up the batteries and controller yesterday.

We are using an "80v" (really 105v max) Curtis 1244. It's an extremely nice controller and I can't help to be impressed with all the features in it. Built in precharge circuit and suppression diode. Manual is 100 pages and the programmer probably has 100+ settings.

Test drive is tomorrow.

Am I dumb, or is uploading pictures harder than I remember it? I can't get them to show up outside a link.
 
Here is a video on my instagram of the car in action. Wet floor, front wheels chocked. No problem smoking tires.

https://www.instagram.com/p/BJTg_Vcj_0H/?taken-by=shelby_electro

Very fun cart to drive. Our carts are already the fastest and quickest production golf cart (when compared to yamaha, ezgo, clubcar) and this car feels a LOT faster.

Sadly, this car is heavy as frock. Wheels don't spin. Can't do donuts. Slow top speed (although that's a good thing imho, my boss is crazy to want this to go faster than 35mph)
I'm not really sure what my boss was expecting. I guess I learned my lesson on managing expectations.

Anyways. I'm happy with it. The cars going to go to one of the dude perfect guys for a bit, and then more PR stuff, and then we'll probably sell it.

Since the electro mechanical work is done, I probably won't be posting in here much more.
 
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