Golf Cart Parts for E-Bike?

[joetemus]

I know the owner of the local golf cart shop, and he will give me (or sell me for very cheap) all the guts of a electric golf cart without the batteries for very cheap. This includes the motor(36V), motor controller, on off switch, etc. I was wondering what you guys thought of using this as a basis for a non-hub driven e-bike.

Requirements
-Minimum distance of 6 miles (to town and back)
-Cheap as possible(This is my first "test" build, with my second build using better equipment)
-Simple, since it is my first build I would like to learn the basics before anything else
-Be able to use the pedals if the bike runs out of juice
-Reach speeds of 30+mph

The Plan
-I plan on straddling the motor over the bottom bar of my bike, and running a chain back to the rear
-Single gear on the back wheel to connect the motor to the wheel(on the opposite side of the pedal chain)
-buy either 6 ub1250 batteries with two sets of three in series (http://www.amazon.com/gp/product/B000YA7SQU/ref=s9_simh_gw_p23_d0_i1?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=04C0RJCHXG2NX4MPHACA&pf_rd_t=101&pf_rd_p=1389517282&pf_rd_i=507846)
or some lithium batteries (again price is a factor for the first build)
-I have pretty much every basic tools (hand tools, multimeter, welder, solder gun, etc.)
-Would prefer minimal welding
- Start with the pedal throttle for initial testing, move to thumb or twist style throttle once working

Questions/Concerns
- I heard somewhere that golf cart motors are typically 300 amps, which would rip my bike apart (~14.5hp)
- Why haven't more people used these motors?
- Would the batteries listed above work? If so how far can I go?
- Where can i find a single rear gear to weld/bolt to my rear wheel?


EDIT : Found a 0.9hp 12v dc that im now going to experiment with 24 or 36v and see how it acts. I don't know much about the motor, and since I'm at college right now I don't have it with me. I will get more information as soon as possible.
Thanks everyone for all the information you have given me. I'm going to use most of the recommendations on my second bike when I make a much more traditional hub motor bike.

 

[parajared]

People don't use motors this big on e-bikes because you need a motorbike frame and wheels to handle that kind of weight and torque. Peddling at this point is pretty lame.

 

[dogman dan]

The biggest single problem involved is that the typical golf cart motor requires the support of the cart drive axle on one end of the motor. You can't just slap a pulley or sprocket on them and go. Other types of DC motors have the shaft supported and and a bearing on both ends, and you can put a sprocket on them easy.

I could be wrong about this, so ask your buddy about it, he knows I'm sure. This is why you don't see cart motors on motorcycle conversions all the time, I believe.

The second thing is it's just overkill. If you get it to work, it will still weigh a lot compared to a typical bike motor.

 

[joetemus]

Ok. This is all what i expected to hear. Yes the golf cart motor has a 19 spline female inlet, so im going to have to make and input shaft, and another bearing on the opposite side to bold the drive shaft in and give it strength. There are a few YouTube vides on people doing this, so im sure I can get something to work. Overkill is fine for what i want, and i plan on just going easy with it. My second bike will either be less powerful, or be able to support that much torque. Since price is a factor im trying to use the components i have.

 

[wesnewell]

Please go to the User Control Panel, select Profile, and then enter your city, state/province, and country into the Location field (country minimum). This will help people help you. Example: Wylie, TX, USA. Without knowing what country you are in it's hard to make any recommendations. Thank you.
You'll probably spend more money trying to do this than you would if you bought a conversion kit which can be had for under $300 shipped.
http://www.ebay.com/itm/Rear-Wheel-Electric-Bicycle-Conversion-Kit-24V-36V-48V-250W-500W-700W-800W-1000W-/290754592384

 

[joetemus]

Thank you for reminding me to add my location. I'm thinking I can keep it under $300 since I have the motor, bike, controller, and some gears already for free, so all i really need are batteries. I also want to have more power than these kits can provide.

 

[dogman dan]

All I need is batteries, capable of handling a huge honking golf cart motor and controller. Oh yeah, that will be cheap.

You will be using a motor and controller 5 times the size of bike stuff, if not more. Requiring similarly overkill battery, unless you are into the concept of use them once, throw them out.
This could be a good plan for a motorcycle conversion, but not a bike.

Battery tends to be 75% of the cost of any EV. So going overkill on the motor just makes that number even bigger. Underkilling the motor is how you save money.

We aren't saying it can't be done. Just that it will be similar to the motorcycle Jesse James built using a semi truck engine. That truck motorcycle ran, and was cool, but not very practical.

 

[pendragon8000]

i would say if you really wana give it a go and its just for fun experiment that might not last too long then get 3 cheap car batteries or small deep cycle.
this video comes to mind... you dont see theese much:
[youtube]1qonMG_zhsY[/youtube]

 

[amberwolf]

If you build a bike around the motor (and batteries needed to power it) you could make it work. But you might want to find something easier to mount on the bike, and make chainring/etc adapters for, like powerchair motors.

If you poke around my old http://electricle.blogspot.com project blog, you'll see a couple of treadmill motor project ideas, which you could possibly adapt the basics of to mounting the GC motor.

You'd still want to get the splined shaft off the old GC so you can cut it and use it to mount your drive system (sprockets, belt, etc) on, though.


The GC controller can easily be used to run the powerchair (or treadmill) motors if you go that route.


But I do gotta say that mounting either PC or GC motor to a typical bicycle isn't all that easy; the only place to put one that isn't in the way of *something* is on a rear rack or rear side pannier type mount, and neither of those is a good solution for maneuverability/stability, cuz that is a LOT of weight up/back there.

Also, it could be a lot of torque, if your batteries can handle the power draw, and you could literally twist the frame up or rip your wheel out of the dropouts, bend the axles, crush chainrings, etc. See that old blog for examples with just the powerchair motors!



Anyway, yes...you can do it. But it will be a challenge to make it fit and work--if you can do the DIY, it would be interesting to see the results!

 

[Drunkskunk]

At a minimum, you're going to need 3 car batteries to run a motor that huge. By the time you mount the motor and batteries on the frame, the weight will be overloading the bike alone, and the torque those motors can produce could easily crumple a light weight bicycle frame. Converting a small motorcycle is going to be a better option.

Its over kill in the same way that putting a car engine on a push mower is over kill.

 

[joetemus]

Alright guys, Thanks for the all the replies. I took your advice and went back to our local golfcart shop with my motor, and after some talk about a smaller motor the owner pulled out a 0.9hp 12V motor used as a starter for the 2 cycle engines. He claims it is not like car starters, because they are designed to last longer, and turn over longer without overheating. It came with a 1/2inch belt pully on the output shaft, and I think im going to remove the gears off the bike and use another 1/2inch pully at the rear and connect a belt between the two. Then use a small 12V dc deep cycle battery and use that to power the bike. The only problem is that I now need a motor controller of some sort. Im looking for some sort of pulse width controller, so I dont burn up the motor using a variable resistor. Any suggestions on a controller for this?

.9*745= 670.5 Watts/12V =max current = 56Amps. I would like atleast a 50 amp controller, that I can easily hoop up to either a thumb or twist throttle on the handbars.

Thanks again for all the help, and making me realize id either kill myself or the bike if I did this.

 

[wineboyrider]

Golf cart motor would be awesome as a lawnmower conversion..

 

[John in CR]

If there's any chance you might slam it into reverse either while running or for a launch from a stop, please be sure to capture it on video and share with us.

 

[Drunkskunk]

That .9hp motor sounds like a better option.

But I would check the brush setup and then experiment with running it at 24 to 36 volts instead. At 24 volts, you need to double your gear ratio, but you'll only need 28 amps for the same power. at 36 volts, you'll only need 19 amps. That will cut the load down on the batteries, and decrease the wasted heat. A 36 volt 20 amp brushed controller is easy enough to find. With only a 20 amp draw, you could run of a much smaller battery without killing it under load.

 

[amberwolf]

0.9hp 12V motor used as a starter for the 2 cycle engines. He claims it is not like car starters, because they are designed to last longer, and turn over longer without overheating.

Keep in mind that most starter motors don't have bearings as such, but usually just brass bushings. So they will wear quickly. Also, they are very high current at low voltages, and as pointed out you'd want to gear it down a lot more (two stages) and run it at higher voltages to help offset the high currents (which will not be good for small batteries).

The only problem is that I now need a motor controller of some sort. Im looking for some sort of pulse width controller, so I dont burn up the motor using a variable resistor. Any suggestions on a controller for this?

A variable resistor that would handle the current you need for that motor will be bigger than the motor *and* it's batteries, and weigh close to what a large car battery would weigh. (I have a couple here; there's pics here on ES and on my old http://electricle.blogspot.com blog of them somewhere; they are from stage lighting controls).

You could use those golf cart controllers for this motor as well, but you'll need to run it at 36V most likely; its probable the GC controllers have an LVC to prevent operation below ~30V, possibly higher. Each one is probably marked for that (or with a model # you can look up and find out).

 

[Arlo1]

Do it you can make a crazy fast ebike with those motors. Here Is what I did with my golfkart motor.
[youtube]Mvm6WN7DWY8[/youtube]

 

[joetemus]

That buggy thing is awesome!

Im struggling to find a large enough motor controller that isnt ridiculously expensive. I'm trying to get some pwm boards but cant find any.

 

[Arlo1]

That buggy thing is awesome!

Im struggling to find a large enough motor controller that isnt ridiculously expensive. I'm trying to get some pwm boards but cant find any.

The controller I used is a simple non programmable Curtis its factory rated at 225 amps and 50v but I opened it up and installed the 11 missing fets and now its a 500 amp 50 v controller

 

[Punx0r]

Does this 0.9HP motor have magnets, or is it series wound? If the later you're on a doubly hard mission: Lower efficiency, worse over heating and monster amp consumption ($$$ controller) than permanent magnet starters, which are trouble enough.

 

[wineboyrider]

Put the golf cart motor in a taco bike frame!

 

[xadmx]

hi i have a( 4qd vtx 24v 40amp controller) it has about 2 hours run time on it, the case is tatty from storage but works fine. if its anygood you can have it for the postage cost i am in the uk tho.
http://www.4qd.co.uk/prod/vtxbx.html

 

[joetemus]

Put the golf cart motor in a taco bike frame!

The next project is a faster normal bike with a powerful hub motor, but once that is perfected I want to put a full sized golfcart motor into one of these
http://www.icetrikes.co/image/overlay/blog-image-ice-2009-recumbent-trike-image-1.jpg
and fly around on that. Focusing on the current project at hand first. Awesome idea though!

Edit:
Also I found a 50A 12-36V motor controller with pwm, that im going to try to use. :? hopefully it works ok. Also bought a few cheaper deep cycle batteries to test with.

 

[dogman dan]

Whoops, there went cheap. You got the hook set now, kiss all your money goodbye, but you'll enjoy it like we have.

Definitely look for a cheap motorcycle frame to slap a cart motor on.

 

[joetemus]

Whoops, there went cheap. You got the hook set now, kiss all your money goodbye, but you'll enjoy it like we have.

Definitely look for a cheap motorcycle frame to slap a cart motor on.

I have about $150 in the first bike, and im not sure what else ill add. Probably a thumb or a twist handlebar throttle. But I got the motor, and bike for free so that helped a lot. I'm definitely spending much more on the second one, because I want that one done correctly.

 

[dogman dan]

Once you get into big performance, you'll empty your wallet on the battery. Just like we have.