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n/a
DELETED (Inactive)
3 Posts |
 Posted - May 25 2003 : 4:06:24 PM
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Hi, i was just wondering about how to go about making an electric scooter, what kind of motor, batteries etc. I have a GP scooter but the neigbours are complaining about the noise. PS could i possible manage to make it on a micro scooter chassis?
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - May 26 2003 : 09:02:23 AM
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I'm actually doing that right now. I found a Razor scooter at the side of the road. It's in great shape, but needs wheel bearings...I'm just waiting for the replacements to come in the mail...
I plan to use a DC motor from a car cooling fan. Pretty strong little things. Have not figured out how I will connect to the back wheel, but it looks like it should be possible to mount the wheel on a short axel and then use a pully and belt or chain to drive off the motor. The concept is going to be low cost (<$50). I will be using 10AH batteries salvaved from old UPS units.
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - May 26 2003 : 5:35:35 PM
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Actualy Aaron you might just want to connect the motor with a wheel. so that there is a wheel on the motor shaft that rubs on the scooter wheel.
Edited by - BEatonNo1 on May 26 2003 5:36:19 PM |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - May 27 2003 : 1:59:00 PM
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I don't really like friction drive. Inefficient, and it slips in the rain. Plus, a chain or belt will allow you to regen down the hills and put a little back into the batteries...
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n/a
DELETED (Inactive)
38 Posts |
Posted - Jun 14 2003 : 1:13:06 PM
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Aaron, I have always wanted to do this but I never knew that it would be that easy. How much would the motor and batteries be new? I only have a scooter.
Anyway, I think tha t I will have enough projects this summer...
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Jun 14 2003 : 6:33:10 PM
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Scooter is almost done. Should be done by next weekend if I get enough time to work on it.
I don't know what the motor is worth "new", but surplus the motors typically go for $15 or so. Same with the batteries.
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romic00
Apprentece
Canada
26 Posts |
Posted - Jun 28 2003 : 10:16:49 PM
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Hey aron did u finnish that scoter? if so post some pics. THX
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Jun 30 2003 : 09:47:37 AM
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Not quite finished yet. I could not find a cog for #35 chain to fit the shaft on the motor (8MM shaft, odd size) so I am having a machine shop make a bushing out of 1/2 rod so I can use a standard 1/2 hub and cog. Unfortunately, due to a holiday weekend, I'm not sure when I will get my bushing. Hopefully late this week. I would do it myself, but there's no way I could drill the hole straight enough since I don't have a lathe or drill press. I would assume the machine shop will just turn it in a lathe.
The rear wheel and axel assembly is all sorted out. It lines up perfectly and runs so smooth. Basically, I cut the existing wheel forks off where they bend to hold the wheel. I welded two places about 2" by 4" to the remaining part of the wheel forks, then installed two bearing flanges on the plates. One flange bolted through horizontal slots, the other through vertical. This means that the bearings can be adjusted to center things up.
The standard Razor wheel was used. I removed the bearings, and installed a set of bushings to bring the 17MM wheel hole down to 1/2 inch. This is where it gets wierd. To fix the wheel to the shaft, I found two large flat washers with center holes roughly 1/2". I also used a 1/2" weld on coller with a set screw. I used a 1/2" bolt to line everything up in a sandwich like this: coller, washer, wheel, washer. The coller was tack welded to the washer, and then holes drilled through both washers. They were then bolted together through the spokes of the wheel. I'll have pictures when I put it up on my site.
I kept the 1/2" shaft in the freezer for a few days to make the metal contract, then I drove the shaft through the bearings and wheel with a few hammer blows. The best part is that this action forced the bearings into perfect alignment, so I just tightened the bolts, installed a coller on the left side to hold the shaft, and drove on the cog to the right side. After everything warmed up, I took it for a test ride and was very impressed.
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romic00
Apprentece
Canada
26 Posts |
Posted - Jun 30 2003 : 10:32:05 PM
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Sounds good i can't wait to see it
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Sep 23 2003 : 5:47:19 PM
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i'm going to do this, but i had an easy and very cheep solution to the linkage problem. ill use a lathe to cut a groove in the whell itself and belt the weel to the motor directly
next stop: nobel prize winner! |
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Kale
Nobel Prize Winner
Canada
795 Posts |
Posted - Sep 24 2003 : 3:56:07 PM
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What are you using for batteries? Lead-Acid Gel? How does your regenerative system work? Do you just apply voltage from the motor/generator straight to the batteries to force current back in? What are the specs of the fan motor (current draw, voltage(12V?), weight, horsepower, etc)
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n/a
DELETED (Inactive)
2 Posts |
Posted - Sep 26 2003 : 03:48:31 AM
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Hi Aaron!
I found your site through Tzi's Scooterworld and am intending to build an electric micro-scooter too. You seem to be pretty much the only person on the web who has tried this and publicised the fact, hence my arrival here.
The idea has only been conceived in the last few days so I have no parts and lots of questions.
My first concern is obtaining a motor: you said you used a radiator fan motor from a Pontiac 6000. Was this just what was available at the time or did you specifically pick this motor for the purpose? I am wondering if a motor from a smaller car would be powerful enough to get the kind of speeds you've obtained, just maybe with less acceleration.
On Tzi's site you say that you got 35 Km/h from 12V with a much higher speed at 24V. Have you tried running at just 12V to see how long the batteries last for? I can do the maths  but was wondering about real world performance. Is the battery pack basically connected directly to the motor or have you got any control circuit in place yet?
When you switch the motor on, due to the high torque involved, what's the acceleration like? Manage to stay on? Does the weight of the motor, etc. make the scooter more or less stable to ride? I think I'd be rather freaked out travelling at 50 mph on a micro scooter!
I like the parallel to series idea of speed control, it gave me the idea of having a larger battery for cruising and another 2 small ones as kind of a 'nitro' boost (now if they could charge on downhills...)
I'm actually thinking of using this as local transport rather than just as a bit of fun, so I appreciate the benefit of your experiences with this.
cirvin: What kind of belt do you plan to use, and how deep will this groove be?
Sorry for all the questions and the HUGE post, but once I get something in my head it won't go away...
Can't wait for more details Aaron! |
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Sep 26 2003 : 06:47:56 AM
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i plan to use one of those motors froma power whls car at first, it will b beltd to the wel with a vacum cleaner belt (th ones frm th flor attachmnt) and som i think gel cell 7.5 ah batts from radio shack. the groov will b just deep enought for th beilt to sit in all the way. ill conctt the batts to the motor by a switch on the handl bars or i will build a controllr later.
next stop: nobel prize winner! |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Sep 26 2003 : 12:03:27 PM
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quote:
i'm going to do this, but i had an easy and very cheep solution to the linkage problem. ill use a lathe to cut a groove in the whell itself and belt the weel to the motor directly
Sounds like it would work, but there may be two problems:
1. Lots of friction (and thus wasted energy) between plastic wheels and rubber belt
2. Dirt and grit will quickly wear the belt and wheels.
quote:
What are you using for batteries? Lead-Acid Gel? How does your regenerative system work? Do you just apply voltage from the motor/generator straight to the batteries to force current back in? What are the specs of the fan motor (current draw, voltage(12V?), weight, horsepower, etc)
The batteries I am currently using are way too small. Current pack is two 12V 2.3AH gell batteries. They aren't that good for high discharge currents, and sag quite a bit. Regen is easy. Simply connect the motor to the batteries using a diode. The only issue is that the motor must be spinning fast enough to generate a higher voltage then the batteries for this to be effective.
My motor is a fan motor from a Pontiac 6000. I don't have any official specs, but it weighs about 2 LBs. Current draw at 12V at stall is around 40A, under load it's about 30A. This makes it roughly a 300W motor, or 0.5HP.
quote:
My first concern is obtaining a motor: you said you used a radiator fan motor from a Pontiac 6000. Was this just what was available at the time or did you specifically pick this motor for the purpose? I am wondering if a motor from a smaller car would be powerful enough to get the kind of speeds you've obtained, just maybe with less acceleration.
It was just available at the time. Really, it is the wrong motor to use. It's a PM motor, and probably very inefficient (knowing the auto industry). Smaller series-would motors would be better, and have much better (higher) torque characteristics. I am currently shopping for a better motor.
Most GM cars use the same fan assembly, so you can find the same motor on large Oldsmobiles, etc. Imports tend to have smaller motors.
quote:
On Tzi's site you say that you got 35 Km/h from 12V with a much higher speed at 24V. Have you tried running at just 12V to see how long the batteries last for? I can do the maths but was wondering about real world performance. Is the battery pack basically connected directly to the motor or have you got any control circuit in place yet?
Range is low because the batteries are way too small. At 12V, about 1KM is the limit. The controller is simply a 12/24V contactor controller.
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When you switch the motor on, due to the high torque involved, what's the acceleration like? Manage to stay on? Does the weight of the motor, etc. make the scooter more or less stable to ride? I think I'd be rather freaked out travelling at 50 mph on a micro scooter!
Accelleration is acceptable. A higher ratio would provide much snappier accelleration, but at the expense of top speed.
I find it very stable to ride. I drove it home from the bar last night after throwing back a few and didn't have a problem. 
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I like the parallel to series idea of speed control, it gave me the idea of having a larger battery for cruising and another 2 small ones as kind of a 'nitro' boost (now if they could charge on downhills...)
Really, just use two large batteries and switch between series and parallel. Remember that when you increase voltage, the motor will want to draw more current. If that current isn't available, you will end up going slower at 24V then you would have at 12. Regen charging works, but don't expect to get any more range from it. In order for it make a difference, you need a regen controller that can keep the output voltage to the batteries higher then the battery voltage, regardless of the output of the motor/generator. Not an overly complicated circuit (buck converter), but certainly alot more trouble then it's worth.
quote:
I'm actually thinking of using this as local transport rather than just as a bit of fun, so I appreciate the benefit of your experiences with this.
Well, then you'll need a large battery pack and a motor/ratio designed for constant low speed use. There are many commercial scooters for <$300 with 30 mile ranges. I would think that if you want decent range (and comfort), a larger pneumatic tired push scooter would be best. You could run a 3:1 tire:motor ratio, and just mount one big honkin Optima Yellow top battery in the middle. That's a 56 AH battery, which should easily give 30-50 miles of range depending on the motor you choose. You can pick a motor that is designed for high RPM efficiency, and choose your ratio accordingly.
Edited by - Aaron Cake on Sep 26 2003 12:04:52 PM |
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n/a
DELETED (Inactive)
2 Posts |
Posted - Sep 26 2003 : 1:47:59 PM
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I have seriously considered buying an electric scooter but due to recent UK and European legislation changes http://www.atob.org.uk/questionselectric.htm it seems that a homebuilt one is the way to go.
I've started coming up with some criteria for my design:
1. Budget is around £100 UK (ca. $225 canadian) from scratch
2. Achieve at least 5 miles range
3. Reasonable hill-climbing ability. Original reason for this project was because I am too lazy to walk up a hill to see my girlfriend.
4. A reasonable top speed would be good, so it doesn't appear that I am riding a toy! (15mph or 25 km/h appears to be UK legal limit)
Forget regen abilities, weight is not too great a problem but it will be needed to be carried up stairs. Simpler the better.
Do you think what you have built so far fulfills most, if not all of these objectives if better batteries were used?
Not meaning to hijack thread!
Edit: Any chance of any video footage in the future? 
Edited by - 999 on Sep 26 2003 1:53:15 PM |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Sep 29 2003 : 09:38:21 AM
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I doubt you'll do any serious hill climbing using a design similar to mine. The gear ratio is too small. Electric motors make great torque, but like anything, there's a limit. If you want to climb hills or go on long journeys, I would recommend a ratio of 5:1 or thereabouts. Problem is that this is difficult to achieve with the little Razor wheels as you quickly run out of diameter for the sprocket. As it is, my 22 tooth sprocket will drag on the ground when I make steep turns. You might have to consider (yuck) spindle drive. Another problem is the batteries. For 5 miles, I would look at 15AH batteries, but just one since packaging is a nightmare. There's just no room on the little scooters to haul that much lead. Perhaps look into advanced batteries such as NiMh or Li-Ion. That's what I'm currently doing. But they're NOT cheap and will kill your budget. And remember that if you're carrying up stairs, a battery that big will weigh 20 LBs. Not alot, but combine it with 10 for the scooter, and several for the motor/misc and you're looking at a 40 LB device. Again, no big deal, but...
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Electric Scooter
