Golf cart based electric motorcycle build.
 

The Goal:
Build an electric motorcycle that can reach 60-65mph for under $1,500.
The Idea:
Use mostly off the shelf parts, using common used/recycled parts whenever possible.
A while back I was thinking about building an electric motorcycle and how the Etek motor is under powered and expensive, some people have used fork lift motors with alot of modifications to the motorcycle frame and the motor, I would use a forklift motor if I could find a standard motor because it seems like a common question people have is "can you build one for me?" if you use a weird motor that is uncommon then the 2nd electric motorcycle is going to require that you start fro scratch, I'm to lazy to do that, once I figure out how to build one I want to be able to make more!
I also don't want to have to cut the motorcycle frame or weld anything other then a battery rack that would bolt to the frame, the whole thing should all bolt together.
The Plan:
Use a golf cart motor, they have a female splined shaft and no end plate with support bearing, so they are hard to use for hobby projects as they are more or less incomplete once they are removed from the golf cart axle, but they are common motors and range in size from 2hp 36v motors up to 12hp 72 volts with some custom made motors out there as well, the advantage of them is that they are common, cheap when they are used, they last a long time and if the motor has the same number of splines it will bolt up (either 10 splines or 19 splines) so you can start with a cheap small motor and if you want to go all out and upgrade to a more powerful motor it's 4 bolts and 4 wires.

So far I have a $100 motorcycle that had a small fire so the wiring is burnt, exhaust is rusted out and has sat without running for 5+ years, I also have contact info for someone who has the same motorcycle with a bad engine bearing for $200 that I might buy as well.
Used golf cart motor was $200 for a 2hp 36-48v series wound motor.
I got a phone call today for a Foxx Power 48v 20amp hour 3c lithium battery with two chargers, I'm told that this battery can handle 60 amp discharge and can handle 100 amps for 15 seconds, anyone with an electric motorcycle already want to tell me if this is high enough discharge rate? the battery is a year old, has two years left on the warranty and would cost me $300 with the two chargers as the friend who has it needs money.

I want this one:

http://www.youtube.com/watch?v=PVv0NVLFPig

I love the way it sits on the line completely silent and when it takes off all you hear is that whine.

I'm doubtful that you can obtain a usable battery pack ALONE for that price that will be able to allow you to reach 60mph.
I was aiming for a $1,000 price point for a 35mph bike and it's now looking to end up costing $1,800 total. And I went with SLAs, and a much lower performance goal.
You'll be surprised just how many small extra parts you will need in order to get the bike running. From thrust bearings, to sprockets, to nuts and bolts.
You will also need a DC-DC converter and a bunch or extra wiring.
Inside or outside?
It better have alloy rims and disc brakes. If not then the wheels are going to have to be replaced because they'll be rusted beyond repair.
That pack is a good price, but it's still WAY too small. I will be blunt and point out that was the size of the battery pack that was in the 800w electric scooter I used to have. It only offered 20mph and 20 miles of range.

You will need a 3kwh or larger pack in order to reach 60mph for more than a mile or two. The further beyond 40mph you go the significantly larger your pack will need to be.
My pack is 60 volts 20AH and at 38mph I'm only likely to get 15 miles of range. 60 amps is one third of what an average golf cart motor is likely to draw under acceleration.
My 2kw peak motor setup was reaching a peak of 80 amps under acceleration.

I would suggest doing a lot of reading at the endless-sphere forums as to what others were able to achieve with what motors and what pack sizes.
Endless-sphere.com • Index page

Obviously I think your goals are very doable, since I have a 2 HP 36v golf cart motor in my daily driver Geo Metro. You will have the advantage of much lower weight, a HUGE plus for your goals. However, the advantage I had was enormous amounts of room in comparison to a motorcyle. To get that kind of speed, you will need high voltage. In my limited research, I haven't seen a 48v motorcyle go much over 50 MPH. If I were to attempt something like this, I'd build the bike as close to free as possible, and get a bucketload of A123 batteries running at 80+ volts with the $1,500. Certainly try out 48v first and see what you get though! I look forward to seeing your progress.....

Tubeless alloy rims with front disk brakes, I would much rather have drum brakes as they have fewer issues but I have disk in the front so that is what I'll deal with.
Part of the idea of using golf cart parts is that they are cheap to buy and the golf cart shop that I got the motor from has a lot of used parts sitting around that he is willing to sell me cheap, more so if I make more then one of these where I can go in with a shopping list.
The Foxx Power battery deal is on hold as the friend realized he would be better off using the trike instead of his car over the summer, so I'm back with lead acid as the planed battery.
I figure my $1,500 goal is going to be with a very basic battery, $1,000 for the bike without the battery, so far I'm at $300, another $150 for a golf cart controller, $100 or so for a charger, I have 20 feet of 2/0 welding cable and a box of crimp on ends that are not yet drilled for the studs, I'm going to need to buy some aluminum for the motor face plate and some steel for the adapter shaft, throttle, pot box, hard ware, it's going to add up but I'm pretty sure it can be done, if not the first time around the 2nr or 3rd I build will be cheaper.

Haven't had as much time to work on this project in the last few days as I would have liked but it is going ahead! my brother stopped by to double check some measurements so he can get to making the bearing holder for the motor, he is also going to make a spare end plate for the golf cart motor so it can be used for other stuff if we want, the end plate for the electric motorcycle is going to be larger then it would normally be as it's going to be large enough to bolt to the frame of the motorcycle where the gas engine bolted in, but first I need to pull the gas engine, I just need to find the time when it's light and warm out.
I'm excited because my brother is going to get class credit for helping me on this project, so he's writing CNC programs to make all the parts, instead of making each part by hand, that way we can make exact copies if it all fits.

That would be nice and if I bought 107 worth of DeWalt battery packs they might give me a price break, otherwise it's $10,000 worth of battery, if I can get it done I might go for $2,000 worth of battery, but not $10k.

This weekend I have plans to pull the gas engine, a number of friends have said they would give a hand, so if all goes well we'll get it out, then we can take measurements of the 2nd end of the spline shaft we will have to make.
I know how everyone likes photos.
http://ecomodder.com/forum/member-ry...ed-next-up.jpg

http://ecomodder.com/forum/member-ry...-golf-cart.jpg

http://ecomodder.com/forum/member-ry...-but-heavy.jpg

That will be one fast bike!

Subscribed!

I have a project bike waiting so I'll be living vicariously.

The engine is out, took two of us around two hours, we got the engine out in the first hour, the 2nd hour the friend that was helping me pulled the air box and a few other odd parts that we don't need any more while I stared at the engine and frame scratching my head, turns out the drive shaft floats around in the swing arm, I thought there was a support bearing at either end of it, not the case, so we did some redesign of the motor bearing plate, adding another bearing, so the shaft that connects the golf cart motor to the motorcycle is ridged enough to support both the open end of the golf cart motor and the unsupported end of the drive shaft/U-join, the advantage of this new twist is that because the drive shaft in the swing arm is unsupported I can tweak it's exact location by a small amount, this turned out to be needed when two bolt holes crossed paths.
The plan for the day is to make a wood mock up of the bearing carrier that also is one of the main motor supports and make sure that clearances are correct before I have my brother write up the CNC program to make the part as there are some curves in the bike frame that make it tight and hard to measure.
I still have not started on specs for the adapter shaft that connects the motor to the motorcycle, but we are getting close, then the motor can be bolted on to the frame and tested.

Due to some alinement issues I had to change my motor mount design, not a great deal but enough that I had to make a trip to buy more aluminum stock, so instead of the motor bolting to a 3/8" by 8" plate, it gets a 3/4" by 6" plate to bolt to, this will be much stiffer and the added thickness allows a bearing to be pressed directly in to the plate that is bolting to the face of the motor, reducing the number of machined parts and reducing the number of bolts needed to hold it all together, by tomorrow at the earliest or this weekend at the latest I should have the motor to a point where it can be bolted on, no splined shaft yet, but that is next on the list! once the motor is bolted on I can start on the battery rack design and figure out for sure how many batteries can fit in the frame, there is more space then I figured at fist and the engine weighed what seems like close to 200 pounds, enough that I needed help moving it so I feel pretty good about the bike being able to handle the weight of the batteries.

Pics, please! :thumbup:

There is not much to look at yet, mostly a stripped down frame, a motor, some chunks of aluminum and a pile of paper with drawings and measurements.
http://ecomodder.com/forum/member-ry...-see-drive.jpg
I did however do some measurements of the frame and the open space and it looks like I should be able to fit 6 T105 golf cart batteries in there without any issue, that is 402 pounds of battery, with the open frame design like it has I'll be able to make a battery rack that sits as low as the engine did, giving me a lower center of gravity, the space under the seat, where the air box sat is 1/2" shy of what is needed for the hight of a T105 battery, otherwise I could fit another in there, one idea is to put saddle bag style racks on the rear for a battery on either side so I can get the full 48 volts I was hoping for, otherwise I could go with a higher voltage battery but I already have 8 used golf cart batteries, lucky for me the motor is designed to spin at around 2,000 RPM with 36 volts and with the gear ratios I have that gives me 57mph, up the voltage and I up the speed.
To give you a taste of the kind of parts we are making to fit this together, here is a bearing carrier that is being put on a shelf due to one of the redesigns I had to do.
http://ecomodder.com/forum/member-ry...spare-part.jpg
The new one looks very much like that but with tabs top and bottom to attach to the motorcycle frame, thus cutting down on the number of parts needed.

Latest photos.
 

I don't have the drive shaft hooked up yet but the motor is pretty close to being able to be bolted in place, it's close enough that I was able to do a mock up, I was also able to take some measurements and everything is still looking good.http://ecomodder.com/forum/member-ry...ed-mock-up.jpg

And a close up of the motor.
http://ecomodder.com/forum/member-ry...ting-shaft.jpg
I don't have the drive shaft made yet but the but I now have all the parts to bolt the motor on, a little bit of tweaking to make the motor fit better and I'll move on to the battery rack.

Excellent!

My bike has a drive shaft too. it will be interesting to see your solution.

Am I seeing that right that you have no reduction? I guess the low rpm of that motor makes it do-able for a shaft bike.

Nice fitment; like the bike was made to be electric.

At one time I found the ratio of the rear gear reduction but I can't find it now, just spinning the rear tire and watching the UV joint spin it looks like a 2.8:1 ratio or so and that sounds about right, either 2.8 or 2.85:1, not sure what other shaft drive bikes run at, but with a bike that has close to an 80" circumference on the tire it seems about perfect, also if I want a faster bike 3,200-3,600 RPM motors are pretty common, as I said before I can even get an affordable 3 phase motor and I think a used golf cart motor plus the CNC parts and adapter shaft is going to cost less then a new Etek motor and should give you more power.
Oranage4boy, what bike are you going to use? I might have some odd parts left over once I'm done if you want to pick up a golf cart motor as well.
My other brother shows some interest in this project as he is looking to buy a motorcycle this summer and said that as long as it goes "fast enough" he would think about it, so I might have a 2nd one going right away if this one doesn't have any weird bugs.

Clev: After seeing what kind of issues this motorcycle has with it's gas engine and doing research on the rest of the bike I would get more and more excited about it every time I would find more info about it to the point that I would get giddy talking about it or even just thinking about it, like that the frame opens up once the engine is removed, the rear gear ratio is near perfect for an electric motor, the fully dressed bike is big and heavy so a striped down version should handle great with batteries, it's really common with new and after market parts avalible, as it really is the perfect bike to be electric, it just needs a handful of odd parts to make this weird motor fit.

This is the bike I always wanted to convert:

Honda Pacific Coast - Wikipedia, the free encyclopedia

Fairly porky because of the large V-Twin and liquid cooling, but it has the advantage of shaft drive, 988 lb. gross weight rating and a lot of room under the bodywork. Ah well, some day...

If I can offer some simple advice:

The engine you pulled out of your Honda is a stressed member, an integral part of the frame/chassis. Make sure you [very] solidly connect the two engines mounts back together when you are finished. A solid connection between the headset (upper engine mount) and swingarm base (rear engine mount) is mandatory, or your frame will snap like a twig and hurt someone.

Very cool project. I've always wanted to attempt something like this with my CB400T2.

Thanks for the tip, as others might not realize that and I forgot to say something already.
The battery rack is going to bolt up to those engine mounting points, I don't have a set design for the rack yet, but I plan to make sure it's ridged enough to stiffen the frame, currently trying to figure out how to get some braces to go from the head tube to the rear engine mounts without getting in the way of the batteries, I think if I use some aluminum plate that goes both between the batteries and under them it will be stiff enough as it will create an upside down "T", however I do it I realize it has to act as a stressed member as well, that is however part of why I chose this bike, no cutting of the frame and no welding of the frame, as that is where you create brittle areas that crack later on.

Looks like an interesting project! I'd do a bit more research before committing to 2.85:1. Most of the motorcycles in the EV album seem to run at least 4:1 - many are around 5:1. Similar motorcycles (shaft drive) seem to universally use a pillow block/aux shaft reduction setup.

With the Citicar / Comutacar, you may have noticed a significant difference in speeds with the two normally available differential ratios. Comutacar/Dana at 5.17:1 are somewhat faster but don't accelerate as well as the Citicar/Terrell 7.125:1. At least for the C-car application, I'd pick something closer to 6:1 (happy medium between speed and acceleration).

Let us know how it goes...

I noticed that they tend to use a reduction between the motor and the shaft, but they also all tend to use the Etek motor as well and that is a low torque motor that likes to run at higher speeds, my motor is said to top out at around 2,000 or a bit higher, bump the voltage up (like I plan to do) and you will get a bit more top end speed out of it, it's also designed to power a 1,200 pound 4 wheeled cart with wide tires on grass with 2-4 people in it, not a 600 pound motorcycle on pavement with silica rubber touring tires and a single person, I agree that I might be pushing what the motor can handle but I'd like to keep it simple and I figure with the gear ratio that I have I'll have to add a heavy duty controller to handle the high amps needed to start from a dead stop.

It looks similar to the motor in your Comutacar - 2000 rpm would be approximately 25 mph which is about where the C-car motor (at least the stock GE motors at 48v) starts to lose torque. But it should do at least 3,500 with no problems.

You're probably right - at 600 pounds the motor won't be working too hard. What kind of controller do you have in mind?

I still need to look in to my controller options, but if I remember correctly there is a 400amp and a 600amp alltrax that work with my setup and voltage, I think that the 600 amp controller would be over kill, but it would allow me to see what the motor peeks at, then swap to a smaller controller and put the 600amp in my Comuta-car as I still have the relay based controller in there.
My goal is to have this motor, when it hits 2,000rpm for the bike to be going about 50-55mph, I know it's asking alot of this motor, so there are some things that I'll just have to wait and see about.

My motorcycle uses an Alltrax 300 amp programmable "AXE" controller.

It is the 24-48V model. When I bought it, I was really split on if I should get the 24-48 or the 48-72V model. 48V has been good, but 72 would be even more fun.

300 amps has been plenty for me.

My cycle is designed for a 45 mph top speed, and uses about a 5 to 1 gear ratio (chain and sprockets) with an Etek motor. I could go with a faster (more amperage required) gear ratio, but that would also hurt acceleration, and I don't think the Etek would love it.

For something like a series wound motor to a driveshaft, higher voltage and amperage controller is probably a good idea.

With my Citicar (older 3.5 hp GE motor - Alltrax 400 amp 48 volt setup) it would pull just over 400 amps for about 1 second, then start to draw less power as the motor sped up. Even flooring it at a rolling 5 mph the GE 3.5 didn't want to draw more than 350 amps or so.

I now have an Alltrax 7245 (72 volt, 450 amp controller but at 48 volts for now) and it uses the same amount of power at 48 volts - just over 400 amps for the brief time the motor is turning very slowly.

My guess is that the amperage may be limited by the relatively small brush wires in the motor (two per brush) - just about every thing else is heavy duty. In my case a higher amperage controller was somewhat overkill.

I'd imagine your golf cart motor won't draw more than about 450 to 500 amps, particularly because of the low weight.

Your on ecomodder, Home of the Open Source Cougar Controller. Y not use one of those?

It will handle 500A and all the way to 144V. You can use any voltage you want with it between 0 and 144.

For the cost of it, you will be less then the alltrax controller and have far more options to play with for optimal performance.

-Adam

My car has a Cougar controller, my motorcycle has an Alltrax, and my friend Chris is building a drive-shaft cycle with a Cougar controller (700 amp version!)

The additional voltage of the Cougar isn't a huge help on a cycle, because cycles are typically lower voltage than cars, just because of how many batteries you can physically fit.

I remember Ryland mentioning the idea a while back of doing kits or just building EV cycles for other people. A name-brand controller may help buyers being more accepting of it, especially having a warranty. I did have a problem once with the Alltrax controller (replaced for free under warranty - their fault - manufacturing defect) and a problem with my Cougar controller (my fault - I screwed up - I had to fix it)

On Chris' EV cycle, we may try to go with a fairly high pack voltage - which will make the cycle INSANELY fun!

In short, I think a stock Alltrax or Curtis would be better for turn-key, semi-mass produced cycles, and the Cougar better for Custom/Fun/Special cycles.

One thing important on an EV cycle is that you have adjustments for your controller throttle response!!!!

I haven't had time to read up on the home built speed controller, at this time I would like to stick with off the shelf parts, mostly so when someone sees my motorcycle and asks if I can build one for them, or if they can build one for them self, I can give them a parts list and keep it simple.
So far most of my time has been spent on part design for parts that can be mass produced, I might have 40-50 hours in to this project so far but when I go to build my 2nd one I'll be at this same mile marker after only 3-5 hours and would like to be able to build one from start to finish in a weekend.
My brother who is helping with the CNC made parts has other projects at school right now and I have alot of projects at work right now so I don't see much progress for the next month, altho I do plan to start on the battery rack soon, thinking welded aluminum plate, altho that is going to require me to set my welder up for aluminum, if I can I want to make the battery boxes large enough for foam insulation to help keep the batteries warm.

I haven't posted an update here in a while but things are still moving along, mostly I've been busy with other projects.
The 3rd and final part for adapting the golf cart motor to the motorcycle is finished! the 3.5" splined shaft that connect the drive end of the motor to the drive shaft of the motorcycle, my brother managed to make 7 of them out of a bar of P20 tool steel that I bought, he said the CNC program to make each one was taking nearly 3 hours total for each shaft, mostly due to the splines and the fact that P20 tool steel is tough stuff, it does produce a nice finish and they fit nicely in to their mating parts.
I only have one of each of the plates and bearing holders that hold the motor and hold the shaft and it's a bit beat up from changes so I now need to do a test fit of everything and make any final adjustments in my measurements then have and get a final drawing done so a small production run of the other parts can be done.
If I get enough time I might even try putting together something that I can ride, I've been busy enough that I still have the Altrax 7265 speed controller sitting around instead of having it installed in my car.

We demand to see photos as soon as you have them! :thumbup:

Parts are looking good! :thumbup:

Hey Ryland! That's an old CX500c isn't it?!
I owned one of those babies.
It's got a nice tough chassis that can take lots of batteries. Can't wait to see what you do with it.

Nice to see an old CX500 with a new lease of life. I think at one point, every courier in London had one - long lived and could take a beating day in, day out. The cycle parts are well up to heavy loading, so have no worries about the battery weight, just make sure the frame's got no cracking and replace the swingarm and wheel bearings as a matter of course.

Its successor, the VT500 was quirky but just as bulletproof.

The swing arm and frame look to be solid, I'll most likely be using this frame as a test bed anyway, as it's missing the speedometer, front brakes need alot of work, seat is shot, turn signals are missing and I can get another bike just like it for $200 or less with a bad engine off craigslist.
The big hicup I've run in to is I was told that the 3.5" shaft in the photo could cost $300-400 each if I wanted more of them made, it will still mean that this will be a very cost effective motorcycle to build as everything else you need to build one is cheap to buy but I think that a single high priced part can turn alot of people away and it's going to push the total price to build one even closer to that $1,500 mark I was hoping to stay under as the motor adapter "kit" might come out to cost $600-700 at this point, another $300 for a used motor and controller from a golf cart shop, $200 for the motorcycle, leaving only $300 for batteries, battery rack, cables and hard ware.

Ouch. Seems a little high, doesn't it? If you decide to make this a kit, you'd probably be able to find a shop that would do them in quantity for half that.

The cost is high because the steel that is being used is really tough and a carbide cutter had to be used instead of a high speed steel cutter, with that a single cutter can only make two shafts before it wears out, it also takes 3 hours to make each shaft on a CNC machine due to the splines, if the shaft was longer and there was more room to over run the cutter then it could be done differently and quicker.

I notice that you are direct driving the drive shaft without the gear box. How are you placing the motor? Off to one side or are you centralising it somehow?
I am building a reverse trike using a BMW K100 transmission complete.
http://i5.photobucket.com/albums/y17...e/DSC01123.jpg

The input shaft is 90mm off centre but the shaft would be 150mm off centre and higher then my prefered motor mount. I am going to use a short shaft but a nice looking one.
http://i5.photobucket.com/albums/y17...e/DSC01156.jpg
http://i5.photobucket.com/albums/y17...e/DSC01155.jpg

The trans gives me a slightly under geared drive for what I wanted, 1.61:1 top gear with a 2.81:1 final drive giving 4.52:1, for my first choice 12" motor so I have decided to use a smaller but hopefully faster 9" motor.


Those shafts look great, though costly!

I was using a similar motor but not having access to anything but a small lathe I had to find a simpler way to make splines.

Turned a blank on the lathe.
http://i5.photobucket.com/albums/y17...s/DSC00350.jpg

Marked out the edges of the splines.
http://i5.photobucket.com/albums/y17...s/DSC00353.jpg

Cut the splines with a 4 1/2" disc cutter freehand.
http://i5.photobucket.com/albums/y17...s/DSC00356.jpg

Fits a treat. (notice the wooden DE bearing cap)
http://i5.photobucket.com/albums/y17...s/DSC00357.jpg

I made three of them in the process of working out how to use the other end.
I settled on this one with a support bearing on the outer end.
I even had to chisel the keyway out with a small cold chisel.
http://i5.photobucket.com/albums/y17...r/DSC00426.jpg

I also used a square of aluminium plate for the DE.
http://i5.photobucket.com/albums/y17...r/DSC00439.jpg
http://i5.photobucket.com/albums/y17...r/DSC00443.jpg

It now drives my tractor.
http://i5.photobucket.com/albums/y17...st03060810.jpg