Hi everyone. Iv spent the last couple days lookingv all over the web for someone I can talk to about creating a cheap electric bike. I already have a mini bike that has a 2 stroke on it but it's cobbled together. Ok there are kits out there for gokarts and all but I'm looking to build this with things I can find laying around. I just don't know were to look for someone who knows what they are doing
Looking for an electric motor expert
- Thread starter bobert1850
- Start date
Ok thanks. Sounds like you might be the person I need. I want to use 18650's for batteries and ether a old drill press motor or an alternator turned into a motor. Thing is, idk how to control speed cheaply or what the motors need from the batteries as far as amps. I don't need a rocketship, just something to get around on.
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Your choice of motors dont sound like long running things .i think You would have better luck with a scooter motor . Ive got some small motors from ebikes i could dig them out if your intrested . As for the speed control your lookin at a pwm driver or a Darlington pare transistors . Unless you have a pile of components look into ebike controlers hook up and go . Did a bunch of lookin into building a ebike from junk some of it easy to get some not so much .
You'd need a ton of 18650s to power a minibike. Lead-Acid lawnmower batteries would be more cost effective.
Drill press motors and alternators are driven by AC (actually alternators generate AC, but they're pretty much the same as a small 3PH synchronous motor). A controller could drive an AC motor but the unpredictable load of a minibike would require the controller to be closed-loop, meaning you'd need to add a hall-effect sensor cluster to the motor. That can get expensive and complicated and in the end, you just made a brushless DC motor anyway. Stick to electric scooter motors.
I suggest you look into Andymark. They have a sweet DC motor controller: Victor SPX Motor Controller (am-3748)
Gearbox: EVO Slim 3 CIM
And motors (you need three motors, each with their own controllers): 2.5" CIM Motor (am-0255)
If you want a possibly more powerful system, check out their Redline motors and Redline 4-motor EVO Shifter.
In the end, considering the expense and the power output, I still prefer gasoline engines. But hey, I'm happy to play with other people's money!
Drill press motors and alternators are driven by AC (actually alternators generate AC, but they're pretty much the same as a small 3PH synchronous motor). A controller could drive an AC motor but the unpredictable load of a minibike would require the controller to be closed-loop, meaning you'd need to add a hall-effect sensor cluster to the motor. That can get expensive and complicated and in the end, you just made a brushless DC motor anyway. Stick to electric scooter motors.
I suggest you look into Andymark. They have a sweet DC motor controller: Victor SPX Motor Controller (am-3748)
Gearbox: EVO Slim 3 CIM
And motors (you need three motors, each with their own controllers): 2.5" CIM Motor (am-0255)
If you want a possibly more powerful system, check out their Redline motors and Redline 4-motor EVO Shifter.
In the end, considering the expense and the power output, I still prefer gasoline engines. But hey, I'm happy to play with other people's money!
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I can get good used 18650s for .11 each and iv seen people build gokarts from an alternator so I don't see why it would be under powered. I have the alternators and other motors already. I can have the batteries cheap and they are not really what I'm worried about. I'm not looking to spend a bunch of money on new stuff. A speed controller and how big of a battery pack will be safe
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Find an open-loop three phase synchronous motor controller (basically a smarter VFD that can sense motor speed through the stator windings) that runs off 48-ish volts DC for under $500. Sounds easy enough...
Okay, say you can find enough 18650s to power Chicago. Forget that's a potential problem for now. How are you going to power the dang alternator??? Find a DC electric scooter motor and go from there. It will be much cheaper that way.
Okay, say you can find enough 18650s to power Chicago. Forget that's a potential problem for now. How are you going to power the dang alternator??? Find a DC electric scooter motor and go from there. It will be much cheaper that way.
Yes, it is very easy to turn an alternator into a motor. I'm very aware of how to do that. The question is: What motor do you turn it into?
Well, I can answer that. A synchronous three-phase motor is what you make. Being it has no means of self-commutation, it cannot run on DC, therefore the controller has to generate three-phase AC at a frequency that matches the motor speed and phase exactly. In order to do that, you would need three hall-effect sensors to sense the position of the rotor and the controller would need to be for a brushless DC motor around 36-48-ish volts. Not to mention, you need a source to provide an excitation to the rotor, just like in an alternator in a car.
I have seen one youtube where somebody bought a controller that was able to sense rotor position using the stator windings in the alternator. I would imagine this type of controller would blow your budget to pieces. Which speaking of, what is your budget?
Now, it may seem like I'm talking bullshit and making up words like I'm telling a joke, but I'm not. Believe what you want to believe.
Well, I can answer that. A synchronous three-phase motor is what you make. Being it has no means of self-commutation, it cannot run on DC, therefore the controller has to generate three-phase AC at a frequency that matches the motor speed and phase exactly. In order to do that, you would need three hall-effect sensors to sense the position of the rotor and the controller would need to be for a brushless DC motor around 36-48-ish volts. Not to mention, you need a source to provide an excitation to the rotor, just like in an alternator in a car.
I have seen one youtube where somebody bought a controller that was able to sense rotor position using the stator windings in the alternator. I would imagine this type of controller would blow your budget to pieces. Which speaking of, what is your budget?
Now, it may seem like I'm talking bullshit and making up words like I'm telling a joke, but I'm not. Believe what you want to believe.
Theoretically, if you had enough 18650s, you could get a good amount of life and power. 18650s are physically bigger than AAs and they have a much higher capacity and peak output than AAs. They give on average 2200mAh @ 3.7V, or about 8Wh per battery. 50 of them would be plenty and at $0.11 per that is no problem.
And yes it is much easier to do an electric scooter drive. Wheelchair drive?:shrug: I don't think they put out enough power for a minibike.
And yes it is much easier to do an electric scooter drive. Wheelchair drive?:shrug: I don't think they put out enough power for a minibike.
Ok so there a bigger then aa i couldn't tell for sure. Would need to build a charger setup they are rechargeable ? As for the wheelchair or mobility scooter they got some good motors in them . 24 volt dc good bearings and sealed. Can move some heavy weigh and if ya look ya can find a busted one for give away .
This speed controller says it will do senseless and 60amp continuous/380amp peak. Would it work? And metal man, 18650s are the batteries tesla uses in their cars, your drill uses, hover boards use, laptops use, power walls use and more. I feel they are the most under rated thing on this planet right now.
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I read you previous post as you thinking I was using the alternator to charge something bc you didn't know it could be changed. That was my bad. I appreciate your help I just don't want to spend hundreds on some ebike motor setup that's Chinese crap built for $5.25 and shipped here and sold for $300. Ik there are better motors to be had I just need to know what to look for. Will a washing machine motor work? If not because it is too weak, why not just add another one in parallel and if I do that, do I need to up volts or amps? Those are the kind of questions I can't answer. I need you to tell me why it won't work, not just say it wont.
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This speed controller says it will do senseless and 60amp continuous/380amp peak. Would it work? And metal man, 18650s are the batteries tesla uses in their cars, your drill uses, hover boards use, laptops use, power walls use and more. I feel they are the most under rated thing on this planet right now.
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[MENTION=15346]metal man[/MENTION] brought up a good point. How do we charge these batteries. You do not want to charge them in parallel because they require a constant current charging mode. Maybe one-by-one in a wall charger?:laugh:
What about using a drill battery? Those are probably better because they can come in 24, 36, and 48V, they have chargers, and they have internal cell balancing. The cell balancing is a very nice feature to have. No cell balancing could = a hole in your leg.
I also wouldn't recommend a washing machine motor because it will produce less power than an alternator and they are typically single phase squirrel cage motors which aren't as efficient or easily controlled.
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Charging is done with a smart charger. They say if you check your cells beforehand, you can USUALLY charge without worrying about individual cells. There's a guy with a youtube channel called jehu Garcia (?) That knows ALOT about this stuff but he builds giant batteries for his vw bus. I used vaping to quit smoking 2 years ago and have chargers to charge 4 batteries at a time but also have a noko genius 3500 that can charge a 12v lithium battery pack. What are the advantages of more volts? And how much do you think an alternator will take? Iv heard up to 300v but idk. Also drill batteries, they are basicly a few 18650s in a pack so I could build some and then run a few in parallel but how do Ik what I need? I can build enough to reach that 300v but I'm sure I don't need it. Do more v = less amps? I'm quite rusty on my electronics math.
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300V would blow up an alternator for sure. Obviously alternators are made to output 12V, but 24V or 36V would be a safe upgrade. Nice thing about alternators is that they sort-of adjust to different voltages because you can vary the excitation current on the rotor.
About the smart charger, does it charge 18650s in a series/parallel or strictly a series configuration? If it does series/parallel does it have balancing?
About the smart charger, does it charge 18650s in a series/parallel or strictly a series configuration? If it does series/parallel does it have balancing?
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Like I said, I just read they could take crazy voltage. And the charger dont have balancing. Idk the exact application it would be useful for as it's designed as a car charger. It's this one below. I'm working on something else today but if that dead ends and I have time, I'll pull the alternator apart and start doing the conversion or maybe get the mini bike from storage and grab the 2 other electric motors that are around to see if they would be better.
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Like I said, I just read they could take crazy voltage. And the charger dont have balancing. Idk the exact application it would be useful for as it's designed as a car charger. It's this one below. I'm working on something else today but if that dead ends and I have time, I'll pull the alternator apart and start doing the conversion or maybe get the mini bike from storage and grab the 2 other electric motors that are around to see if they would be better.
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