Homemade e-bike questions. Golf cart starter motor

[joetemus]

http://i.imgur.com/49f8Ow7.jpg

SORRY ABOUT THE UNFLATTERING SETTING FOR THE PICTURE I was in a rush

Im almost done with this homemade e bike and had a few questions for you guys. Im running a 1hp (maybe .9hp? I cant remember) golf cart starter generate motor, with 2, 12V scooter batteries in parallel connected to a 12V 50A motor controller. If you need more specs let me know.


I was wondering if you think the gear set up will be enough. I have a 11 tooth gear in the front on the motor, and i just bought a 60 tooth gear to attach to the rear. I used the stock rear cassette, but there wasn't enough torque to get going, so I figured this gearing should be better, but is it enough??

Also, is it legal to ride this as a bicycle if I don't have pedals? I'm assuming it should be ok, because I can argue that there are pedal-less bikes.

Finally, I think my twist throttle only goes to about 2k when the initial pot on the motor controller went to 5k. I may be reading this wrong though, because I ordered a 5k throttle. How big of a deal would it be if I put a 1-2k resistor in series with one of the 3 lines?

 

[spinningmagnets]

I would add pedals, even if they are not attached to anything. I have seen E-bike frames with a straight-across bar where the pedals normally go, and it caught my attention.

If you happen to run into someone who is going to hassle you about not having pedals attached to the drive, it won't matter whether you have pedals or a foot-rest bar, but...I think the less attention you draw to the fact the bike is not really pedal-able, the better it will be for you...hassle-wise.

 

[joetemus]

Ok, If I'm going to move the motor I might as well do it now. I'm probably going to move it to behind the seat, unless you have any other suggestions

 

[Dauntless]

I think you'll lose your argument on the pedals in court, as our 'Beloved' Senator Boxer says, Government isn't here to help you, it's here to FINE you. You'll find threads where people have a freewheel on the cranks and it also serves as a jackshaft.

I get the idea the pinion on the motor is for a more motorcycle chain that won't work on the sprocket you have. I find it surprising you say you already tried using it. Why not reverse your motor and drive a sprocket on the opposite side? Ever see one of the "China Girl" moped conversion kits on a bicycle? The sprocket clamps to the spokes on the opposite side.

http://www.bikeberry.com/engine-kit-parts/drivetrain.html?limit=all

I just wonder how well a starter motor will hold up in continuous use. Those are designed to be overloaded for a short burst. And what about the solenoid? I don't think that will hold up under engaging/disengaging all the time while you're moving. Did you rewire and take it out? I also wonder how fast it is spinning . My understanding of the starter is it might get over 400rpm, which would give it a kv around 35. Just remember that when the engine starts and the starter remains engaged, you hear it wind up. I did a quick search for people who tried using them for a go kart and what I found is they all wind up disappointed, looking for another motor.

First thing is, you say it didn't have "Torque." Did you mean it was just slow? Ongoing discussions here of overclocking motors. The consensus has been raising voltage and lowering amps increases the rpm without the heat issue I'd expect you to have with that motor. Though there's a lot of metal there, Mr. Physics would back you on that choice. One of the karters was talking of unspecified higher voltage when he was seeking 3,600rpm and thought he only got 2,000, probably just a guess on his part. But if you had maybe 1,000rpm you only need the 26" bike wheel at close to 400rpm to go 30mph, so that 11t front would like the 36t back from bikeberry and MIGHT go 25mph.

Remember this is all guesstamites. I just don't think we can learn the proper kv for that motor without an automotive engineer who knows how to find out, you'll our R&D on this. But I speculate that you might be happy at 36v and 20a. The motor might be at 1,200rpm, 36:11 might get you 30mph. You might get much the same results with 24v/30a and a smaller rear that I can't tell you how to find. If you just had all this money you could experiment with everything, right?

Oh, don't know what your controller is, but you might have to replace it to do all this.

Of course if we find someone who really does know the subject he might blow all that out of the water.

 

[gogo]

Also, is it legal to ride this as a bicycle if I don't have pedals? I'm assuming it should be ok, because I can argue that there are pedal-less bikes.

The statutes specify 'operable pedals' for the ebike subcategory of bicycles. If you go without pedals you'll be in the motorized bicycle definition and you'll be subject to the clown shoe law:

A moped must be equipped with a safety flag that extends not less than 5 feet above the ground attached to the rear of the moped. The safety flag must be triangular in shape, with an area of not less than 30 square inches, and be Day-Glo in color.

 

[joetemus]

I get the idea the pinion on the motor is for a more motorcycle chain that won't work on the sprocket you have. I find it surprising you say you already tried using it. Why not reverse your motor and drive a sprocket on the opposite side? Ever see one of the "China Girl" moped conversion kits on a bicycle? The sprocket clamps to the spokes on the opposite side.

the sprocket on the front has the correct pitch, but was to wide, so I narrowed it with a lathe, and it works great, so that isn't the problem. I also have no problem with gear placement when building it. I can either put it on the same side as the current sprockets(leaving a few gears for pedaling), or the other side.

I just wonder how well a starter motor will hold up in continuous use. Those are designed to be overloaded for a short burst. And what about the solenoid? I don't think that will hold up under engaging/disengaging all the time while you're moving. Did you rewire and take it out? I also wonder how fast it is spinning . My understanding of the starter is it might get over 400rpm, which would give it a kv around 35. Just remember that when the engine starts and the starter remains engaged, you hear it wind up. I did a quick search for people who tried using them for a go kart and what I found is they all wind up disappointed, looking for another motor.

First thing is, you say it didn't have "Torque." Did you mean it was just slow? Ongoing discussions here of overclocking motors. The consensus has been raising voltage and lowering amps increases the rpm without the heat issue I'd expect you to have with that motor. Though there's a lot of metal there, Mr. Physics would back you on that choice. One of the karters was talking of unspecified higher voltage when he was seeking 3,600rpm and thought he only got 2,000, probably just a guess on his part. But if you had maybe 1,000rpm you only need the 26" bike wheel at close to 400rpm to go 30mph, so that 11t front would like the 36t back from bikeberry and MIGHT go 25mph.

When i tested it with the current gears it wouldn't even go on flat ground and just blew my 50 amp fuse. but that was with like a 25tooth gear (now I have a 60 tooth). The motor is also a "starter generator" from a golf cart. It is designed to turn over a golf cart a lot more often then a car starter motor would have to start a car, and I don't believe this will be too much of a problem, if it is I will pick up nice hub motor for it.

Also, your saying that running 24v through it would probably not be such a bad thing? I would really like to run 24V through it for more power and speed, but I'm worried about blowing the motor.

 

[Dauntless]

http://endless-sphere.com/forums/viewtopic.php?f=2&t=54355

There's any number of threads here moving up and down the voltage and amperage, I just don't remember the titles.

Starting more often is not the same as running continuously. Not really designed to run any longer than a car starter at any moment.

http://www.diygokarts.com/images/starterpics/150/Starter%20Modification.pdf

 

[joetemus]

Well im hoping that since the max distance i have to go is 2ish miles itll last for a little while. If not i will just buy a better motor. This motor was free anways!

 

[Drunkskunk]

If that motor was also used as the generator, I'm betting it's RPMs will be in the thousands. 20mph at the back wheel will be around 260RPM, so you'll need more than 11:60 reduction.

 

[Dauntless]

No. It'll perform as a starter motor performs. I'm assuming it's strictly DC, but I don't know anything about his controller. The starter function will run at the speed it's expected to run at to start the cart. I can only guess around 400-450rpm. It'll be physically capable of spinning at 6-8 times the rpm to generate more current, but it doesn't run at that speed when you power it. My understanding is any motor can be a generator, any generator can be a motor, you just have to wire it for such. But as with the socalled "Regenerative Braking" there isn't nearly as much coming back as it takes to make it spin.

 

[Dauntless]

First of all, watch his difficult start. Compare it to yours.

Starter Motor Powered Bike 24V (With 12V Motor)
The bike has been upgraded. Now it has an additional battery to give the motor a bit more speed.

Micscience 9 months ago
Is this bikes starter cooled in anyway besides the air?
Reply · .
Paul Seeley 9 months ago
No. That is why it overheats easily

MrOrangeConeRacing 1 year ago
I am currently thinking about going to the salvage yard and snagging 4 or 5 starters off of like cars and using all of em together. That way each motor works less to get going, it would pick up speed crazy fast. I would most likly be able to use a normal bike sproket or close to it. I wana build a Electric Drag Bike. I'm shure that the more starters used at once, the more ass it would haul. I also plan to use a cooling system.
Reply ·
Henzzman 1 year ago
starters have the front part of the shaft mounted on a bearing,but the bottom part just sits in a hole with some lube.youd have to fit bearings to all of them and then weld somesort of small tanks or pockets on their bodies to cool down the brushes.otherwise the fun will be short lasted.also you will need some pretty impressive batteries to power 4 or 5 starter motors.if you have enough money,then id reccomend optima redtop ones.

[youtube]1qonMG_zhsY[/youtube]

 

[Dauntless]

http://tncscooters.com/index.php?route=product/product&path=41_74&product_id=188

So that's just one example of a controller you could try out, this site has others. You got me thinking about all this. Better than thinking about tonight -- I mean, it wasn't a DATE, but she was there, and, uh. . . .

Anyway, this controller runs at various voltages, comes with a throttle, etc. You can try it out up and down the spectrum.

And it's easy to let my imagination embrace this $20 starter. http://tncscooters.com/index.php?route=product/product&product_id=531

 

[joetemus]

Alright guys. Thanks for all the help. I got that huge sprocket on last night, and unfortunately i would need another gear change, in the middle somewhere, because that isnt enough. All it ends up doing is blowing my 50 amp fuse when running 12 and 24v, so i think i just bought a few 24-48v 600 watt motors that already are geared down, so that the max speed they spin i around 480 rpm. Which will be perfect. Maybe ill leave the starter motor on there and have it so i can turn that on at higher speeds so it's less likely I'll blow a fuse.

More then likely though I'm going to end up doing a complete redesign, consisting of a new battery box, with 48v worth of lipos (rc plane ones maybe since they're cheap), unless its really expensive. Then ill just end up going with 2 more 12v batteries to make 48v. I will probably upgrade my motor controller, because mine kinda sucks. Id also like to move the motor to under, or behind the seat so i can put those pedals back on.

Any tips on a motor controller? I can solder, so adding different mosfets isn't a problem. Id like to get an over powered one so if i upgrade somedat i hopefully wont need a new controller.

Thanks guys.

 

[amberwolf]

You might want to look at my CrazyBike2 thread, which includes links to the old electricle blog that has more info and previous stuff on it, about various brushed motors and controllers and how they worked out for me.

 

[Dauntless]

http://endless-sphere.com/forums/viewtopic.php?f=3&t=54427

It finally occurred to me to make an 'Amp Check' for starter motors. Because I suddenly remembered the expression that we all know so well" "500 Cold Cranking Amps." Hmmmmm.

Reading in performance forums they were talking some big fuses for the V8, even 4 cylinders were recommended 300amp fuses. 1000cc bikes 200-250amp. The little Aprilia SR50 scooter was said to have a maximum draw of 61amps, so a larger than 61amp fuse is in order. Your larger than a 50cc engine starter will need a larger fuse than that Aprilia.

Important notes, I HOPE they know what they're talking about:

No load amperage was apparently at best 1/4th of the load amperage. (Can you hold the wheel up and run it with your controller?) One guy was complaining ". . . .Seems like it's drawing a LOT of amps just to turn over. . . ."

One specific golf kart starter generator was stated to draw 30amps no load. Another 40amps. If that's 1/4th. . . .

RC engine starters are drawing 20amps.

You never named your controller, but I'd say it's not good enough. Too bad the guy in the video didn't name his controller.

 

[joetemus]

You never named your controller, but I'd say it's not good enough. Too bad the guy in the video didn't name his controller.

My motor controller is a canakit 12v-50amp one, so I put a 50 amp fuse on it to protect it. It blows that 50 amp fuse when I'm on it once I hit around 7-8 mph. I can wind it up no problem when I hold the back wheel off the ground

 

[Dauntless]

http://endless-sphere.com/forums/viewtopic.php?f=2&t=54410

What I've finally started to understand after reading some recent posts is why I've always been told an electric motor out performs it's ratings. A 1500 watt motor would 2hp but feels more like 4hp. That's because the 4hp gas engine is going to run continuously at 2hp but can only deliver 4hp when you wind up the rpm. The electric will run at overload when you first start it and give you the 4hp, but can't keep doing it so once you're going it's gotta get down to 2hp.

Which means that the motor can overload your controller if it's too big. I think it's your controller that's the problem. You can't just put a much bigger fuse in there, that would melt the controller. But starters are built to draw the amps.

So I guess this is something you built yourself. It might be good for a little 250 watt motor. It says you can run it up to 24 volts, might be worth a try with a little cheater of a 60amp fuse.

Maybe someone has some ideas for building one of these with bigger or more mosfets or something to draw more amps.

http://www.canakit.com/50a-dc-pwm-motor-speed-controller.html

http://www.canakit.com/lcd-display-module-uk1133.html