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View Full Version : Success! Discharging batteries, heating motor up.



Wirecutter
11-05-2006, 08:55 PM
Success at last! I still have no working brakes, but that would take some of the fun and challenge out of it.

http://www.youtube.com/watch?v=CykCx1xLEzQ

I'm using the cheapest car starting batteries I could find, so a full charge got me about 40 minutes of pretty hard run time. I took the kart up to the corner store for an errand, and got more than a few looks. I changed out the original drive sprocket, so it's now geared a bit taller. I guessed correctly that the reason it won't light them up from a dead stop is because of the damned accel curve programmed into the controller. Got to get a programmer and fix that.

It turns out that by the time the batteries were pretty much flat, the motor had heated up quite nicely. So the battery charge life is the fail safe for not frying the motor. Of course, as you can see, it was being run pretty hard. :D

I couldn't stop grinning. Now I'm trying to decide on whether to improve this one, making it faster, or move on to the next one. Maybe add brakes and sell it off to finance another project?

-Mark

barts
11-05-2006, 09:17 PM
Very cool. That's got plenty of scoot; the same setup would work pretty
well for a small electric motoscooter for around town. You may wish to
use deep-discharge batteries instead; they'll survive much longer than
regular car batteries. What also helps is not flattening them completely;
stop at 10.8 volts or so for longer life.

- Bart

JIMofalltrades031
11-05-2006, 09:19 PM
Sweeeeeeet! And you can add braking to the motor. It probably corners like it is on rails huh?

Dawai
11-05-2006, 09:33 PM
The Happy look on your face makes me feel good.

You will be amused to know this new pitt pup has a taste for electrical wiring also like the last one did.

He has carried more tools outside than I can find. Butch had a whole set of screwdrivers and I never found them.. I guess he buried them.

I was showing my wife the USB camera mated to a huge lens, Holding the two in my hands getting the focal points close.. THE pup looked at her, then me, then leaned over and pulled the usb plug from the laptop.. if I had not saw it, I would not have believed it. He is jealous of anyone coming close to me.

Fasttrack
11-05-2006, 10:23 PM
Very cool! Thats a a pretty sweet acceleration - how much power do estimate that thing has?

i need to shoot a few pics of my go-kart

all made from gas pipe as yours but man...everytime i see a go-kart pic on here it is made about three times heavier than mine. I waiting for mine to fold up in the wind...but it keeps on trucking

that pipe is pretty good for go-kart frames!

charlie coghill
11-05-2006, 11:16 PM
And the neighbors saying there goes the G-dam kid again. :D
Very nice.

Rigger
11-06-2006, 06:11 AM
You will be amused to know this new pitt pup has a taste for electrical wiring also like the last one did.

He has carried more tools outside than I can find. Butch had a whole set of screwdrivers and I never found them.. I guess he buried them.

I was showing my wife the USB camera mated to a huge lens, Holding the two in my hands getting the focal points close.. THE pup looked at her, then me, then leaned over and pulled the usb plug from the laptop.. if I had not saw it, I would not have believed it. He is jealous of anyone coming close to me.

There goes another proud animal sacrificed on the alter of bigotry, stupidity and ignorance.
Owners need licenses, not animals.

Rigger.

Ed Tipton
11-06-2006, 07:19 AM
For a moment there I was angry...then I realized that in fact it was not my wife you had caught on camera. She uses the same cornering technique in our driveway, and on our streets, but she has a tendency to not always stop when she should. Nice rig!:D

Wirecutter
11-06-2006, 12:12 PM
There goes another proud animal sacrificed on the alter of bigotry, stupidity and ignorance.
Owners need licenses, not animals.
What??? A little OT here, but I have to say...

I don't consider Mr Cofer bigoted, stupid, or ignorant. I also don't believe he mistreats his dogs in any way, unless spoiling them counts somehow as mistreatment. If you've followed some of the history - the guy just seems to wind up with mischievous dogs. I get a laugh out of his screwdriver-stealing, wire-chewing dogs. Seems ironic that an electrician's dog likes to tear up wiring. :D

-Mark

Wirecutter
11-06-2006, 12:20 PM
Sweeeeeeet! And you can add braking to the motor. It probably corners like it is on rails huh?
That it does, that it does. The controller has regenerative braking, but don't think the power returned to the batteries amounts to very much. It's more like using the batteries as a big load to dump braking energy into.

The handling is very crisp, almost twitchy. It feels to me a lot like the karts I've ridden at a local track. Frankly, I'm absolutely delighted that it came out so well.

I was thinking of trying to clock the max speed, and maybe get a measurement of lateral acceleration. I don't know what I'm getting in the lateral, but I know it's a lot. The automotive press measures lateral G by seeing how fast a vehicle can go and stay within a circle of certain diameter, I believe. "Drifting" also doesn't count. Maybe I can setup a test like that?

I've already got the second battery on the charger - they should all be good by tomorrow evening. My head is swirling with new ideas, now. Should I make another, or make this one "stronger, faster, better"? This thing is such a hoot. :D

-Mark

sidegrinder
11-06-2006, 03:49 PM
I am still fairly new to the world of high-speed internet, and I must say some of these videos are too cool! Somebody pass the dramamine!!!

BillH
11-06-2006, 04:10 PM
suggestion, It looks like the CG is low enough to not be a concern but a seatbelt and roll bar may be a good idea. Looks like a lot of fun! Is that a golf cart motor?

speedsport
11-06-2006, 04:57 PM
Rigger,
Do you have to work at being a loud mouthed prick or does it come naturally?. I have read many, many of David Cofers posts and One thing is for certain, he is neither ignorant or stupid!, I, and I am sure many others enjoy reading Davids folksy posts and knowledgeable answers. You sir, on the other hand, have contributed exactly precisely nothing of any value to this forum. Do us a favor and spend your time on Adrians page, you two will make a loverly couple.

rsr911
11-06-2006, 05:19 PM
There goes another proud animal sacrificed on the alter of bigotry, stupidity and ignorance.
Owners need licenses, not animals.

Rigger.


I'd suggest checking the attitude at the door. David is very kind to his animals and if you took the time to look up the history you'd know that. He's also a very helpful guy, the kind you shouldn't judge too quickly.



Cool go-cart!

Wirecutter
11-06-2006, 05:34 PM
suggestion, It looks like the CG is low enough to not be a concern but a seatbelt and roll bar may be a good idea. Looks like a lot of fun! Is that a golf cart motor?
Yup. Bought it off FleaBay from a guy that got a pallet of them. Folks he got it from develop golf carts or burden carriers or some such.

Well, yeah, I guess it lacks some essential safety features, like roll cage, seat belts, or even brakes. I doubt I'll need a roll cage unless I hit a curb sideways, though. It's very heavy and low, and the tires aren't the grabbiest. It likes to slide, and so do I.

The brake disc and caliper have been on the kart all this time, but I don't have an actuator (pedal or handle) or a cable rigged up. With such a tight turn radius combined with a live axle, it stops pretty neatly by just doing "S" turns, believe it or not. I'll probably do some preliminary tests on the mechanical brake to see if it has the needed power. I'm skeptical, and I've been thinking about going hydraulic anyway - it's easier to route hoses than a cable or rod actuator.

I went ahead and sprung for the programming pendant for the controller. I want to see what the kart will do when it actually thinks it's supposed to go fast, rather than keep from spilling golf clubs. :D

-Mark

hornluv
11-06-2006, 06:28 PM
Don't you just love cul de sacs?

BTW, I think rigger was saying that Pitbulls have gotten a bad rep in the media. I don't think it was anything against David.

Dawai
11-06-2006, 07:15 PM
8 meg movie of the abused pup eating peanut butter.
http://img.photobucket.com/albums/v85/ibewgypsie/th_LexPeanutbutter.jpg (http://smg.photobucket.com/albums/v85/ibewgypsie/?action=view&current=LexPeanutbutter.flv)

http://img.photobucket.com/albums/v85/ibewgypsie/Lex_carrol.jpg
http://img.photobucket.com/albums/v85/ibewgypsie/lex_sleep.jpg

I got bullied all the way through school, till they put me in a black school in the late sixties, then I got bullied all the way to high school, I quit school in the 9th grade and went to work in construction. I worked with a crew of ex-coal miner electricians that would hit you with a hammer if you didn't bring back the right part quick enough. Times were hard on a poor boy. It has taken a long time to get over the hatred I felt for 99% of the humans on this earth. At 16 I moved into a boarding house and started buying my own groceries, I developed into a 275lb man with a 32 inch waist who could throw a chevy 327 into a car trunk. NOW my waist is much bigger and I have calmed down some. I have not been hit with a hammer in thirty three years.

I never fit in anywhere, except a motorcycle club, and with my dog. AS you can see, the dog picks up part of the personality of the owner. He is a character already.

You guys are pretty neat, perhaps we can all meet for a goat roast some day. (he ain't sleeping in my tent till we roast him)

rockrat
11-06-2006, 07:37 PM
Dave!!! So gald to see you 'round. That pup is getting big.

I must admit, I was jelous when you first got it. So, I got me one of them full bred dogs. I found a German short hair pointer and decided that you had so much fun, it might be ok to have another dog. This one is too smart for me. But she is great. Points a pheasnt like you would not believe. Along with the cat right before she chases it through the house!

BUT!!!!!!!!!! Back to the topic, Wirecutter, that go-cart is killer. I would say that's more fun than a fellow should legally have!

Nice job!

rock

j king
11-06-2006, 08:27 PM
Thats neat.I like how quiet it is.It needs a little more on the bottom end and then you could drift.Have fun.

Your Old Dog
11-06-2006, 09:02 PM
Slick, slick project! Looks like a ball :D

How did you come across the motor for that project?

ray........

Your Old Dog
11-06-2006, 09:06 PM
With such a tight turn radius combined with a live axle, it stops pretty neatly by just doing "S" turns, believe it or not.

So Officer Dudly Doright pulls up to the curb gets out of the car and motions you over and you're gonna pull up on him doing some sashays and s turns? :D :D

I had no clue you could get that kind of muscle out of a golf cart motor!

BillH
11-06-2006, 09:06 PM
Hearing stuff about pitt bulls is no replacement for expirience around them.
My old neighbor's pitt bull was one of the nicest dogs I've been around, sure my uncles Cat would say otherwise. The dog is definetly not an alpha.
Now I dont care what dog it is, when you got a couple of them in a pack, in that pack mentality, thats when you should be fearful. Theres always one that is an alpha thinking he's the king. I had to get dog pepper spray when exercising up in New York before I came down to Florida. Never had to use it, heads up thinking was a better defense. One dog I am careful around, as in, if he is staring at me from a distance, I know not to go near him, if he is walking around, not caring about me, its safe. 2 Dogs, I dont care if they are pugs or golden retrievers or what ever, all bets are off.

Your Old Dog
11-06-2006, 09:09 PM
I never fit in anywhere, except a motorcycle club, and with my dog. AS you can see, the dog picks up part of the personality of the owner. He is a character already.

You guys are pretty neat, perhaps we can all meet for a goat roast some day. (he ain't sleeping in my tent till we roast him)

I always thought you fit in here real well. Always enjoy your post and glad to see you spending some more time on this board. Just don't be so cruel to that pup :D Peanut butter with no jelly, you ought to be shot!

BillH
11-06-2006, 09:12 PM
I always thought you fit in here real well. Always enjoy your post and glad to see you spending some more time on this board. Just don't be so cruel to that pup :D Peanut butter with no jelly, you ought to be shot!
I second that! Glad you are back.

darryl
11-06-2006, 11:39 PM
Mark, if you're wondering what your next go-kart project might be, you could always build the next model using two of those motors. The rear axle would be split and each side driven by one of the motors. You wouldn't really need the axles in line with each other- one could be ahead of or behind the other by just enough to accomodate the bearings. That way, each axle gets two frame members to bolt it's bearings to, for rigidity and control. Mount the driven sprockets outboard of the frame, just inside the wheels. Neither axle interferes with the others sprocket. The motors could still be mounted in-line with each other.

Current draw wouldn't increase for steady running, but would peak twice as high during accelleration. Of course, that would be twice the accelleration of the single motor system (not that you'd want that :)). I don't know if your controller would be up to that, but maybe. If you went with two controllers, you could theoretically eliminate the steering wheel. Instead you'd be steering by wire, by varying the balance of power delivered by the controllers. The front wheels would just castor. Heck, you don't have brake pedals, why not get rid of the steering column too. :).

From seeing the kart and watching the video, I'd say much of the squealing from the tires is because of the straight axle. As you suggest, that's also where much of the braking comes from when you do esses. That function would lessen with the two motor system, as would some of the twitchiness.

What might you call this new model- the Discharger?

kap pullen
11-07-2006, 09:25 AM
Wirecutter,
What size motor are you running, watts, amps, and rpm?
That's a great project.
Kap

Wirecutter
11-07-2006, 10:51 AM
So Officer Dudly Doright pulls up to the curb gets out of the car and motions you over and you're gonna pull up on him doing some sashays and s turns? :D :D
Fortunately, when I did the test ride, everyone seemed to be elsewhere watching the Redskins game. I was kind of counting on the fact that, being electric and therefore quieter, limited riding of the kart on public streets would generate more funny looks than complaints. I'm not pushing my luck, though. It helps to let others take it for a spin. :D



Wirecutter,
What size motor are you running, watts, amps, and rpm?
That's a great project.
Kap
Hmmm. Funny thing is that I don't have exact specs on the motor. I had meant to get the part number and look up some info, but forgot.

It's made by Advanced DC Motors, but I think it's a non-standard part number. (Edit: I see from one of the photos that it's a part number AY6-4003.) It was made for Columbia Par Car, and they make industrial vehicles like pallet mules, factory "scooters", and something called "burden carriers". The nameplate says it's a 36v motor, and I think it's rated for about 4.5 HP continuous. With electric motors, the rating is always for the continuous, but they peak a lot higher. I seem to recall that similar motors can develop peak horsepower as high as 15. The programming of the controller determined that the max current into the armature is 300A, and I believe 100A into the field. It's a "separately excited" motor, not a series wound, so it has to have a controller. I really don't understand how it's different, though. I've had it apart (of course), and it has 4 big field windings around the perimeter of the main motor housing - those go to two of the exterior terminals. The other two terminals go to a set of brushes, then to the armature, where the windings on the armature are energized.

With a series wound motor, you can just hook up the armature in series with the field, apply juice, and it goes. Not so with this one. Perhaps someone could enlighten me?

Regarding the live axle - yes, I think a fair amount of the wheelspin is because of the solid axle. Another player, though, is that the controller, which was pre-programmed when I got it, has a slow acceleration ramp. I purchased a programmer for the controller yesterday, so the programming will be the first thing I'll change when it gets here. I still don't know if the kart is capable of lighting up the tires from a stop going in a straight line. One way or another, it will be. :D

I've already made considerations for going to a 72 volt system - that would either put two more batteries on the sides, or have one over each rear wheel. That would also require a rather substantial investment in a new controller, since the Sevcon can only run up to 48v. This all goes to what may amount to a complete powertrain upgrade, I suppose. That will in turn mean that I'll have to find a smaller, peppier home for the old motor and controller. I also have a rear axle, from drum to drum, from a golf cart - maybe I can use that to make some kind of utility truck for the shop.


Somebody help me - I can't seem to stop.

-Mark

Dawai
11-07-2006, 09:44 PM
IF I understood your question? The winding magnetic fields give the armature magnetic fields something to attract and push off of.. INstead of magnets around hte perimeter it has real electro magnets?

Is that what you asked? I am pretty tired, Bill Gates kicked my ass again on the cnc.. This time it was a dirty ide cable.. I am so tempted to put the old solid state 486 in that puppy.

It has been squirrely since butch pulled hte wires out of it thou. Sometimes the quill starts on it's own. I keep the brake on when changing tools.

Wirecutter
11-08-2006, 12:59 PM
David -
Sorry to hear of your PC hassles. I'd love to see you and Bill in a room together. :D

About the motor - yeah, I figured the business with the (electro)magnets pushing against each other. With both a "separately excited" and series DC motor, you put amps into the field, and amps into the commutated armature windings, and your motor runs. With a series motor, you can just wire the armature and field in series and off you go. Not so with my separately excited motor, but I haven't a clue why.

There is some advantage in some situation in using a sep-ex vs a series motor, but I don't know it. I think I'll switch to regular series motors.

-Mark

topct
11-08-2006, 03:40 PM
"There is some advantage in some situation in using a sep-ex vs a series motor, but I don't know it. I think I'll switch to regular series motors."

You won't get the results you are getting with the setup you have with a series wound motor. You would have to go to brushless and that would be very pricey for that kind of power.

By being able to vary both the field and armature voltage you can get better efficiancy out of the motor. And if the controller were to be able to sense current, I would assume it does, its going to run the motor real well. A form of engine management system.

Be carefull with that reprogramming.

I'm not sure but I think they still might be running electric busses in Seattle WA. because they can climb some very steep hills that diesels can't. Using that type of motor.

Elninio
11-08-2006, 11:53 PM
of course you realise you are a pioneer... thats awsome! maybe u can sell them!

Elninio
11-08-2006, 11:58 PM
http://www.youtube.com/watch?v=-C-jdm6sXNI&mode=related&search=

this one is faster - looks like youve got yourself a competitor :D

darryl
11-09-2006, 02:11 AM
Whatever you do, don't go with the collidel silver batteries. Besides turning your motor blue, you'll be forever having accidents. :)

Wirecutter
11-09-2006, 10:29 AM
http://www.youtube.com/watch?v=-C-jdm6sXNI&mode=related&search=

this one is faster - looks like youve got yourself a competitor :D

Ya know, I saw that guy when I was showing someone my video. He really did good, but he did it the easy way - he converted a regular racing gokart. I've thought a lot about his implementation, though. I looked at the Briggs Etek motors - the type he's using. I didn't think it would be powerful enough, but maybe I'm wrong. The Etek is also a permanent magnet motor, IIRC, and therefore has a more limited RPM range where it really delivers the power. I also didn't notice what kind of batteries he's running. With a full charge, my kart could probably double as a UPS for a time. :D

I would have to estimate that me and my kart weigh twice what his setup does. That would also be a big factor. I'm not sure, but I suspect the drivetrain on my kart would be a bit heavy on a normal kart frame. I have something like 120lbs of batteries alone. I also don't have the best tires on mine, but even so, it grips surprizingly well.

All this has gone to what improvements I'd like to make for the next kart. Chrome-moly tubing, rather than that incredibly heavy iron stuff would be a start. Having a tubing bender would allow me more flexibility in the shape and strength of the frame. There's a particular controller/motor combination that I believe I've fallen in love with. (fa$t, fa$t, how fa$t can I afford to go?) Although it would add weight, I'm considering going with a "jack shaft" configuration so I can run a wider range of gear ratios and still use small diameter tires like the ones normally seen on racing karts.

(A jack shaft would be coupled with 1:1 ratio to the axle, and would be driven by a big reducing sprocket that was driven by the little sprocket on the motor shaft. I have a 60T sprocket that I can run on the rear of the Neurotikart, but its diameter is nearly that of the rear wheels. I wouldn't want it to touch the ground, now would I? That's one reason the rear wheels are so much larger than the fronts on the kart now.)

I wish I didn't have to do all this pesky work for money - I could spend more time in the shop.