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Mav80
Apprentece
USA
26 Posts |
 Posted - Jan 24 2012 : 7:33:38 PM
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I've been thinking about making an elctric go-kart using some of the frame kits and throttle control packages they have online but it seems like they're all made for gas engines. I have a theory that if I get a gas/brake pedal setup I can somehow wrap the throttle cable around a twist-grip throttle. That way, when the pedal gets pressed it will rotate the throttle too. Is this practical? I would just get a gas engine, but from the little bit of looking I did, it seems like gas is waaaay out of my budget of $450 max.
Thanks in advance for any suggestions. |
Edited by - Mav80 on Jan 26 2012 10:03:52 PM |
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Jan 27 2012 : 12:12:30 AM
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A quick google search shows that 450USD is about what you'd pay for the frame alone, not counting any power source.
Electric is probably not going to be cheaper than a gas engine of comparable performance. You'll need to buy a motor, a controller, and batteries to power it all.
As far as the throttle idea goes, it could work, but replacing the twist grip with a linear potentiometer might be easier mechanically. |
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Mav80
Apprentece
USA
26 Posts |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Jan 28 2012 : 10:38:37 AM
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Gasoline engines are pretty cheap these days. If you have a Harbor Freight store, they sell imported engines of reasonable quality, quite cheaply.
Or visit the local scrap yard because is always yard equipment scrapped with an appropriate engine.
Anyway, if you want to go electric, then what about one of the pedals here?
http://www.electricscooterparts.com/throttlesstandard.html
Or you could cut apart a standard twist grip throttle and add a spool (visit an auto wrecking yard and pull one off a throttle body). |
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Jan 28 2012 : 2:39:02 PM
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I do love the idea of electric vechiles, but to be honest, gasoline engines are how you wanna go for lower costs.
http://www.harborfreight.com/predator-212-cc-ohv-horizontal-shaft-gas-engine-certified-for-all-states-except-california-68120.html
This engine will outperform the 1kw electric system in most respects, and costs less than half of an electric drive system (don't forget about your batteries).
I once saw someone build a dangerous go kart from a creeper, engine, and some wheels from harbor freight, it was pretty zippy, like a powered louge with no brakes! I can't imagine it cost them more than 300USD.
Also, don't forget that your frame isn't gunna come with much else besides the static frame, you still need to get all the moving bits, wheels, steering yolks, brakes, etc.. those can add up quick. |
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Mav80
Apprentece
USA
26 Posts |
Posted - Jan 29 2012 : 10:55:24 PM
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After doing some serious research, I think I may have gotten the cost down to about 350USD. I dropped the pre-made chassis idea and have decided on building one out of gas piping, like the one here: http://hight3ch.com/electric-go-kart/ . That will take 100USD off the total cost.
After looking into gas engines and the California motor vehicle code, it looks like electric is the safest way to go. Especially considering the number of cops in my neighborhood. I'd hate to spend all that money just to have it impounded by the cop around the corner.
Another Idea I got from the link above is to ditch the pedal Idea and go with hand controls.
As you can see, I've done a lot of thinking over the past couple days, but I think I've got something figured out. But with new ideas come new questions, so bear with me if possible.
First of all, for the live rear axle, how would I mount a sprocket like this: http://www.monsterscooterparts.com/35chsp44to1m.html Would I have to buy a hub or freewheel mechanism?
So far I have figured out:
motor kit+batteries: 230USD
Steering assembly: 84
Steel pipe: 25
Thanks for the suggestions guys, I really appreciate it. |
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Jan 30 2012 : 11:38:59 AM
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It won't matter if it is gas or electric, if you drive your kart on the road, you're gunna get in trouble with the cops. You can't drive an unregistered vechile on public streets, and you can't register a go kart for street use because it won't satisfy safety requirements. As long as you're on private property, you should be safe though.
Hand controls will probably be the easiest to control, I suppose you could argue that they're safer too, acting as their own dead man switch.
Looking at the electric components you have specified, I would take the money you save on the frame and buy better batteries. Driving a 1kw motor, you'll trash 9 Ah units fairly quick unless you drive very conservatively. Never hurts to invest in your batteries!
That sprocket will need a hub to attach to.
You have a design for your frame? |
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Mav80
Apprentece
USA
26 Posts |
Posted - Jan 31 2012 : 8:29:06 PM
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It looks like I may be getting another source of income so I'll probably go up to 48v with 10ah batteries.
As for the frame design, I have it at 4ft long, and 16in. wide in the front. The back is a little bit wider, 1.5 feet. It's pretty much the same design as the link I posted earlier: http://hight3ch.com/electric-go-kart/ .
I've been thinking of trying to make a simple 2 or 3 speed gear setup, just using 3 different gear sizes, probably 72, 54 and 33 tooth. To keep the chain tight I was thinking of using a bike deraileur, but it probably wouldn't hold up to the motor torque. Do you guys have another Idea? |
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cirvin
Nobel Prize Winner
USA
1542 Posts |
Posted - Feb 01 2012 : 10:27:41 AM
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Increasing the battery voltage won't be a good idea here, your motor and controller are designed for 36v, you risk damaging one or both of the components with a higher voltage. What you need is higher capacity batteries. That motor you specified will pull almonst 28 amps at full power, thats almost 3 times the capacity of your 10Ah batteries. At that rate, they're no longer 10Ah.
http://homepages.which.net/~paul.hills/Batteries/BatteriesBody.html
^Some decent reading about batteries in electric drives.
A well designed electric system should't need much in the way of gearing systems, but if you still want them, you'll probably have trouble with a bike chain, they're not mean't to go too fast with lots of torque. Try looking for a small motorbike transmission to mate to the motor if you wish.
http://www.diygokarts.com/vb/showpost.php?p=176648&postcount=13
^a good post about the topic.
Long story short, a single ratio for an electric kart is plenty good, any more just adds complexity with very little rewards. You'll do best to put as much money as you can into getting high capacity batteries. The major issue with portable electric drives is the power source. |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Feb 02 2012 : 10:25:44 AM
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I've done the hand control on a go-kart thing and honestly, it sucks. Feels too much like driving a weird 4 wheeled motorcycle because you then need handle bars instead of a steering wheel. Limited rotation means turning radius sucks.
A sprocket like that is designed to be welded or bolted onto a hub. You can get a hub at the local bearing/equipment store, just make sure to match the OD of the hub with the ID of the sprocket to avoid having to machine.
You probably won't find a freewheel to fit that sprocket so it will need to go onto the motor. Electricscooterparts.com has a number of freewheels. Or, you don't really need one. I've never put one on any of my electric vehicles. It opens up the possibility of regen braking.
Pulling 30A from a set of 10Ah batteries isn't an issue, it just means that Peukert starts to kick you in the butt. But with only 10Ah ride time would be limited. 30+ Ah is where you should be looking.
48V should be the minimum voltage to consider. At least 2KW worth of motor as well.
A transmission is a good idea, but really not needed unless you are intending to run at very high speeds. If you really want a transmission, an older used motorcycle transmission from a small bike is the way to go for almost no money and if you buy a common one, you can get aftermarket gears at any ratio. A bike derailleur has worked in the past, as you can get strong bike chain (remember, a bike rider will put out several hundred ft-lbs of torque).
To be honest I think the frame out of pipe idea is terrible. It's going to be 5x heavier than if you just made it out of aluminum channel or square tubing. |
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Mav80
Apprentece
USA
26 Posts |
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Gas/Electric go-kart
