Golf cart based electric motorcycle build.

[Ryland]

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.

[Ryland]

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.

[thatguitarguy]

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.

[captainslug]

Originally Posted by Ryland

The Goal:
Build an electric motorcycle that can reach 60-65mph for under $1,500.

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.

Originally Posted by Ryland

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

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.

Originally Posted by Ryland

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.

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

[vpoppv]

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.....

[Ryland]

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.

Originally Posted by captainslug

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.
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.

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.

[Ryland]

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.

[Ryland]

Originally Posted by thatguitarguy

I want this one:

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.

[Ryland]

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.

[orange4boy]

That will be one fast bike!

Subscribed!

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