Author Topic: Electric Motorcycle build question  (Read 9655 times)

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divemaster1963

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Electric Motorcycle build question
« on: June 12, 2010, 10:46:18 PM »
I have been finding parts to build a electric motorcycle. I have found a 27 volt bus AC motor with dual shafts.  The frame is a Kaw 440 frame. and the batteries are deep cycle 12volt Gel. the controller is a 300 amp golf cart unit. the on board charger is a 36 volt Minny cart charger. The lites are all led 12volt plus a 25 watt headlite.I have a 4 speed transmission for the motor. chain drive to trans then chain to rear wheel.

My Question is what could I expect milage wise. I am trying for apx 50 miles at a top speed of 60 with a cruising speed of 40 to get to work and back. terrain is rolling hills with mostly gradual grades.

 any suggestion would be appreciated.
Build on temporary hold till fall. wife broke hip. :'( so am doing in house projects for now.

john

Bruce S

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Re: Electric Motorcycle build question
« Reply #1 on: June 14, 2010, 08:39:05 AM »
    The 4-speed tranny which is probably built in the to Kaw could be a drain on the system. The AC motor really will not need a tranny, only thng need will be neutral and go.
With the AC motor down at 27V you may have problem getting up to 60mph due to weight and its limits. You might be able to with gearing, but seriuos doubts.
The distance can be calculated by current draw, if you have the faceplate, post the info and we can see what it'll take.
Biggest thing will be using the 36V controller and getting AC out of it. PWM will be a big factor for this.

Build can certainly wait, but we can do the numbers first then you can assemble later.
Sorry to hear about the wife, take care her first and best wishes for a speedy recovery!!
Bruce S
 
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REdiculous

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Re: Electric Motorcycle build question
« Reply #2 on: June 14, 2010, 10:13:25 PM »
I don't know what's common for motorcycles but a 21" diameter tire spinning at 1000rpm would have you going about 62mph. A slightly larger diameter tire means slightly lower rpm for the same speed and then the opposite is true as well..

If the motor is beefy enough to handle it then ditch the tranny and gear for a max of 60mph. The push trailer for my bicycle is geared for 45mph at rated rpm and it can push me from a stand-still no problem. In my case it's a treadmill motor and a 9:1 ratio..not quite motorcycle level but eventually it won't be too far off. later :)
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divemaster1963

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Re: Electric Motorcycle build question
« Reply #3 on: June 15, 2010, 08:50:04 PM »
I'm sorry for the confusion. I have had little sleep sense my wife broke her hip week ago sunday. had surgery Tues morning. st oped breathing wed night. almost lost her due to overdose of med by doctor. just got her home today.

The motor is DC not ac. the motor is from the Air conditioner blower off a transit bus. ???

thankyou for any info you have.

Tinbendr

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Re: Electric Motorcycle build question
« Reply #4 on: June 15, 2010, 09:57:08 PM »
Check out these guys, maybe they can help you out.
Nothing is foolproof because fools are so ingenious!

zap

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Re: Electric Motorcycle build question
« Reply #5 on: June 15, 2010, 11:00:02 PM »
I hope you wife is doing better.

As to your question of
Quote
what could I expect milage wise
You haven't provided near enough information.

You mention deep cycle 12v gel but you give no size.

You don't give an amp or wattage rating of the motor but let's assume the motor is rated 20 amp.  Overvolted to 36v (which would probably be OK for a 27v motor) will give you 720 watts.  This is just a SWAG but... you're kaw is going to need somewhere around 5000 watts in order to hit 60mph.  Efficient gearing can bring the wattage requirement down.

A former member here has done a lot of experimenting with this kind of stuff.  His web site is:
http://www.theworkshop.ca/ (most of the EV stuff is under the "Energy (Renewable)" link)
This one in particular used a kaw KE-175 converted to electric:
http://www.theworkshop.ca/energy/dirt_e/dirt_e.htm

The site Tinbendr mentioned is good as is http://endless-sphere.com/forums/index.php

It sounds like a fun project John... keep us updated?

Bruce S

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Re: Electric Motorcycle build question
« Reply #6 on: June 17, 2010, 11:25:35 AM »
I'm sorry for the confusion. I have had little sleep sense my wife broke her hip week ago sunday. had surgery Tues morning. st oped breathing wed night. almost lost her due to overdose of med by doctor. just got her home today.

The motor is DC not ac. the motor is from the Air conditioner blower off a transit bus. ???

thank you for any info you have.


No worries on the confusion, we can understand to need to not be into this stuff right now.
First take care of the wife, good ones are hard to find these days.

Now that it is DC, can you grab a picture of the information plate? If it is similar to the buses around here the voltage is going to be pretty high, good for efficiency, might be a challenge for battery arrangement and chargers.

Zap is also correct come back with some more info on the batteries you have on hand as well.

Best of luck and sue the pants off the DOC!!! at the very least complain to the medical review board...

Bruce S
 
 
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divemaster1963

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Re: Electric Motorcycle build question
« Reply #7 on: July 18, 2010, 05:31:51 PM »
OK I finally had a little time now the wife is feeling better.
I picked up one of the candidate motors Sat.
It is a Thermo king

1.4 hp
1700 rpm
27 volt dc
51 amps

If I push this to 36 volts I think that would make possibly apx. 2000 watts of power. If I can get the gearing to get the rpms up I think it may work. If I can get 50 mph for short durations like 5miles That would get me into the 45mph zones in the city.
I also came across a died 24 volt scooter. I think I can use the throttle speed controller and maybe the speed controller. It is one of those cheap Chinese ones that sold for 250-300 dollars about 4years ago.  I'll get photos up on the motor and the scooter as soon as The rain will permit.

What are the thoughts of success of the Idea?

john 

Bruce S

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Re: Electric Motorcycle build question
« Reply #8 on: July 19, 2010, 12:07:09 AM »
OK I finally had a little time now the wife is feeling better.
I picked up one of the candidate motors Sat.
It is a Thermo king

1.4 hp
1700 rpm
27 volt dc
51 amps

If I push this to 36 volts I think that would make possibly apx. 2000 watts of power. If I can get the gearing to get the rpms up I think it may work. If I can get 50 mph for short durations like 5miles That would get me into the 45mph zones in the city.
I also came across a died 24 volt scooter. I think I can use the throttle speed controller and maybe the speed controller. It is one of those cheap Chinese ones that sold for 250-300 dollars about 4years ago.  I'll get photos up on the motor and the scooter as soon as The rain will permit.

What are the thoughts of success of the Idea?

john 
Hope all is well.
pushing the motor from 27 to 36 will allow the motor to get up to speed much easier without too much of an issue, but since you will be pushing the motor well over a 20% increase of it's rated voltage, you might need to have a close look at the windings. Make sure they are up to the task and can handle the extra work. You'll be trying to ask them to work an extra 500 watts.

The cheap set might be okay for testing , but I would not rely on them for very long. Most of these were/are built for the throw away society and may be even at their limit when pushed at 24V, going to 36V on these may let out the magic smoke.
You may be better off building a PWM for it and use the 5k POT throttle to go from stand still to wide open. Let gearing and tires get you up to the speed.
At 36V and if you can get the full 51A, that 1800+ watts so you certainly need a good sized battery bank.
I would shoot for being able to take it 15 miles at the 45mph and set your battery range for that.

Welcome back

Bruce S

   
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RP

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Re: Electric Motorcycle build question
« Reply #9 on: July 19, 2010, 12:18:36 AM »
If I push this to 36 volts I think that would make possibly apx. 2000 watts of power.

Be careful about exceeding the max current rating.  One of the possible outcomes is demagnetization of the magnets. 

You can use the additional voltage to increase the torque at the upper rpm range but don't apply it at stall or very low rpm.

divemaster1963

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Re: Electric Motorcycle build question
« Reply #10 on: July 21, 2010, 08:08:51 PM »
Good to be back.
I have gotten my hands on a controller and a twist grip reo. I have had a unit just like this apart. the brushes are the biggest that I have seen for this size motor. the winding wire is as thick as no.2 pencil lead. I have taked to the bus manufacture. he stated that the motor is rated to handle upto 72 volts. they over built them for the transit authority. he stated that they will handle the 36 volts with no problem. I asked about servicing the brushes.( the ones on the motor are new.) he said that they are the ahrder ones due to the constant use and that they should last 4-5 years in the use that I am using them. shorter running times and less stress on the unit its self.
 Now to find the proper frame ???. I am leaning towards a 250-400 size bike to hold the bank of batteries. I am working with a battery supplyer to fine the best ones for the wieght and dimensions for the frame. once I get the frame we can work that out. I am going to stay with wet or gel. don't have the funds to do lipo batteries. ( not yet anyhow.) 8)

jimovonz

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Re: Electric Motorcycle build question
« Reply #11 on: July 22, 2010, 01:51:43 AM »
If you are planning to use the 1kW electric motor as a direct replacement for the original (~20kW) motor, I think that this will perform badly. I think that even 2kW is not enough to get that machine up to 60mph. A quick search shows that the original 440 got around 4l/100km on the open road. A quick n dirty calc shows if we assume that the engine is 35% efficient then this equates to an energy output of 11.6kW (at an open road speed of 100km/h ~62mph using an energy content of 30MJ/l). I'm not sure of how well this figure correlates to the instantaneous power required to maintain 60mph (I can see a few problems with this assumption). If you can get access to a functional 440 (or similar bike) then its not too hard to get a more accurate figure for any particular speed. The procedure is to measure the average deceleration at a given speed and using the weight (combined bike + rider) work out the energy loss. Say you want to work out how much energy it takes to maintain 100km/h. Get the bike up to 110km/h and throttle off completely, measuring the time it takes to decelerate to 90km/h. For example t=5 seconds. The weight of the 440 tanked up is 184Kg + 86Kg rider = 270Kg The energy at 110km/h = 1/2mv^2 = 0.5 x 270 x (110/3.6)^2 = 126kJ where the energy at 90km/h = 0.5 x 270 * (90/3.6)^2 = 84kJ So we can estimate the average energy loss at 100km/h as (126-84)/5=8.3kW This figure represents the total amount of energy that you would have to put in to maintain 100km/h. If you just throttle off and leave the bike in gear then you are including the friction loss in the engine so by engaging the clutch you can exclude the engine losses but keep gearbox losses. Its been quite a while since I've owned a bike so my 5 second estimate could be way off however the method should be correct.
If you are pushing the limit of your motor power wise then you would want to be real sure of its performance curve before you determined its suitability (either direct drive or with a specific gearing ratio). Is the speed rating you have its max allowable speed, no load speed or its speed at the rated power? Is the power figure you have its max input power or max output power? What is its efficiency? These factors have a huge effect on system design. For some very basic DC motor info read this: http://lancet.mit.edu/motors/motors3.html

dnix71

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Re: Electric Motorcycle build question
« Reply #12 on: July 22, 2010, 11:42:51 AM »
I have an electric assist bicycle with a 400 watt motor. A 2 kw motor would be real nice, but it will not move a motorcycle anywhere. You need at least 5HP (brake HP, not name plate, to move a small motorcycle at highway speeds. There is actually a legal requirement of that nature for certain roads in the US. You won't see the signs much anymore but it would be something to the effect that "5bhp or more is needed to drive this highway."

divemaster1963

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Re: Electric Motorcycle build question
« Reply #13 on: July 24, 2010, 12:11:08 AM »
Thanks for the math. cal and trig Have not been used in a good while.( have forgotten more than I ever learned at William and Mary ) I hope to get a bigger motor but with limited funds and the desire to just toy and experiment with gearing I am going to try withthe 2kw I have zero in the project. and am interested in working mechanical problems from the pants up. like to get hands in and neck deep to see how things can be worked out Thur some trial and error. to me that makes it fun. The speed is more of a desire than a must. The batteries are donation from the battery company for media promo when i get it up and going. the local green city coalition wants me to let them show it at green days when I get it running. The DIY angle. plus It's FUN. I like the idea of alternative local travel. the city has 12 electric vehicles with only 9 running. The depts. don't like them. I want to prove them wrong. that they do have a place and with a little maintenance can be reliable. They think all you have to do is jump in then and go. They forget you have to charge them up.

I keep all posted on the findings and progress.

john