# Need a reasonable controller!!!



## ithinkidontknow (May 14, 2009)

So I am building a small EV project and for this project, I expect I need about a ~100amp controller in order to feed current to a 24 volt permanent magnet motor from some deep cycle batteries. I can't really tell what the specs for this motor are, all I have is the small picture below to gauge off of. Is the 104amps usually the maximum? 
My question is, would I be able to get a huge potentiometer to limit the current enough to be able to have a variable current? I would probably rather find controller that works with what I need instead of having to using just a potentiometer but the only thing I can find that is even close are 250+ amp controllers that are $350+ which is definitely not in my budget!

Anyway, if anyone has any idea how I can do this I would really appreciate your help!


----------



## Amberwolf (May 29, 2009)

No, you won't be able to use a potentiometer to do this. 

If you really want to try that, I have a wirewound lighting dimmer meant for stage lights that can handle 1000W at 220VAC. But it weighs about 20+ pounds, not including the mounting frame around it, and is as big as a small birthday cake. 

Also, that's not a permanent magnet motor, because that little rating chart shows a field current rating, too, which means it uses a field winding instead of magnets to give something for the armature windings to push against. However, it's shunt wound instead of series wound, which means that you can power the field separately with a constant amount of power, essentially making it work like a permanent magnet motor, and allowing you to use a controller designed for PMDC motors. 

The 104 amps (armature) and 6.5 amps (field) are probably the loaded value, given the 2.5HP rating.


Some motors (like my Invacare powerchair motor on my ebike) are rated at their no-load value, which in it's case is 3.6A. It's way more than that if I put any load on it, though. Probalby 4 times that, at a guess (I haven't got a way to directly measure it yet, because I am lazy since it works right now).

You could check with Richard at http://4qd.co.uk since they make low-voltage controllers for EVs such as golf carts, garden trains, scooters, etc. The 4QD-300 will do up to 240 amps for one minute, at a price of 245UKP for the 24 to 36V version (I think it's only a little more for the 48V version). If you heatsink it better than the box it comes as, it'll handle the same current for longer. 

If you're handy with electronics, you could build your own controller, too, since it will work with PMDC controllers if you power the field separately rather than from the controller. There are a few easy-to-use chips like the MC33035, which was made for BLDC but can also be used for PMDC brushed motors, and then you can use a few well-heatsinked NTY100N10G MOSFETs in parallel to handle the current.


Now, another question: What size EV are you thinking of? Because a 2.5HP motor won't move very much mass if you want it to go fast (it's the same rating as on my treadmill motor). It might run a good-sized bicycle or a scooter or moped, or a small motorcycle chassis (remember the weight of the batteries you're going to use!).

That motor you have is spec'd at what looks like around 1300 or 1400 RPM (probably no-load), so if you gear it down a lot so you get more torque out of it, you'll lose speed. Were you going to hook it to a transmission, or just use belt or chain reduction?
________
Infants avandia


----------



## ithinkidontknow (May 14, 2009)

Amberwolf said:


> Also, that's not a permanent magnet motor, because that little rating chart shows a field current rating, too, which means it uses a field winding instead of magnets to give something for the armature windings to push against. However, it's shunt wound instead of series wound, which means that you can power the field separately with a constant amount of power, essentially making it work like a permanent magnet motor, and allowing you to use a controller designed for PMDC motors.


I didn't think it was a permanent magnet motor, but the seller I bought it from lists that it is. Anyway, you seem to know quite a bit about this so I was wondering how much you think this sort of motor might be worth because I got it for $75 and I am wondering if that is too high or not !


Amberwolf said:


> You could check with Richard at http://4qd.co.uk since they make low-voltage controllers for EVs such as golf carts, garden trains, scooters, etc. The 4QD-300 will do up to 240 amps for one minute, at a price of 245UKP for the 24 to 36V version (I think it's only a little more for the 48V version). If you heatsink it better than the box it comes as, it'll handle the same current for longer.


Have you ever worked with this company before? Also, 245 UKP is around 400 in USD so this is still way over my budget! I will definitely look into this and see if I can find anything else on the website.


Amberwolf said:


> If you're handy with electronics, you could build your own controller, too, since it will work with PMDC controllers if you power the field separately rather than from the controller. There are a few easy-to-use chips like the MC33035, which was made for BLDC but can also be used for PMDC brushed motors, and then you can use a few well-heatsinked NTY100N10G MOSFETs in parallel to handle the current.


I am definitely not very handy with electronics; this project is essentially serving as a learning project for getting into electrical engineering! (I just finished my first year at a university) So building my own controller may be out of the question. 


Amberwolf said:


> Now, another question: What size EV are you thinking of? Because a 2.5HP motor won't move very much mass if you want it to go fast (it's the same rating as on my treadmill motor). It might run a good-sized bicycle or a scooter or moped, or a small motorcycle chassis (remember the weight of the batteries you're going to use!).


This EV should only weigh about 200 pounds by itself (100 of that is batteries) with me as a 200 pound rider. I have another post around here somewhere about my project but I am still trying to figure out what to do for the electronics. It is essentially a bicycle-based tadpole three wheeler. My goal for the project is to be able to go up to ~25mph and travel >10 miles on a charge. 

Now back to business, I have some questions that are probably fairly easy for you to answer but I haven't a clue. Is it possible to wire let's say, 3 identical smaller controllers (maybe around 40 amps continuous) in parallel with each other and then hook up all the potentiometer wires of those controllers to a single potentiometer, and then wire all the outputs to a single wire that goes into the motor? Just a thought but with my limited knowledge it seems possible!

On a side note, I thought it was pretty cool that I actually stumbled upon your "electricle" page earlier today when I was trying to look for others who had built electric bicycles. Cool work!


----------



## Amberwolf (May 29, 2009)

ithinkidontknow said:


> I didn't think it was a permanent magnet motor, but the seller I bought it from lists that it is. Anyway, you seem to know quite a bit about this so I was wondering how much you think this sort of motor might be worth because I got it for $75 and I am wondering if that is too high or not !


I don't know prices on motors; I get most of my parts from stuff other people throw away, including the motors and batteries I have now. Freecycle.org is a major source of parts for me, as are local thrift stores, yard sales, and trash piles. 

FWIW, if you paid that much for it, someone else probably will, too. Just be honest about exactly what it is, and take a good clear photo of it's label (in sections if you have to), for them to see the specs for themselves. 

Craigslist is easier than Ebay to sell on, from what I hear from friends. I haven't any experience with either yet (except a few things bought from Ebay back a couple years or more). 




> Have you ever worked with this company before? Also, 245 UKP is around 400 in USD so this is still way over my budget! I will definitely look into this and see if I can find anything else on the website.


I ran across the company in searching for info about PWM controllers and how they work, when I first started looking into building my own, and was just repairing the first controller I got (a burned out one on a Scoot'N'Go from a thrift store). Richard helped me out a lot with technical information and questions. If I had any money to spend on things, I'd've bought one of the 2QD controllers, because I can change out the MOSFETs on it for the ones I listed (which I use on my repaired controller) and then use it for whatever motors I might ever use on my ebikes. 

4QD controllers have been used in a lot of things, including Robot Wars robots.  I see them mentioned here and there whenever I start looking up info on controllers. One of the more famous ebike projects, by Eric Peltzer, used 4QD controllers. 





> I am definitely not very handy with electronics; this project is essentially serving as a learning project for getting into electrical engineering! (I just finished my first year at a university) So building my own controller may be out of the question.


Well, if you can read schematics and solder, you could build a controller based solely on the application notes in some of the motor controller chips (like the one I listed before). If you can't do either, you're probably going to have to save up for a prebuilt controller.

Keep in mind that depending on the EV you will use the motor on, you might not need that high a current capability. Most controllers (any good one) ought to have a current limiter that prevents you from drawing more current than it is designed to handle, and cuts out if it overheats. I'd guess that many controllers could handle overcurrents longer if you have a bigger heatsink or active cooling on them. (or both). 

If you're willing to void the warranty on whatever controller you buy, you can also change the MOSFETs on it for larger ones, or simply parallel a lot of the same MOSFETs already on it onto a large heatsink panel. That doesn't take much electronics skill to do, and there are a bunch of project sites I've run across where people did similar things with pictures and some instructions. 



> This EV should only weigh about 200 pounds by itself (100 of that is batteries) with me as a 200 pound rider. I have another post around here somewhere about my project but I am still trying to figure out what to do for the electronics. It is essentially a bicycle-based tadpole three wheeler. My goal for the project is to be able to go up to ~25mph and travel >10 miles on a charge.


That sounds like you could get away with this motor just fine. There's a calculator on 4QD's site for what power rating you will need for given vehicles, too. (there are also others around the web)

Where do you live? I ask because different states have different restrictions on what a bicycle helper motor can be, power wise, and how fast you can go. Here in AZ, there's no specific definition for electric ones (just gas motor displacement limits), but there are HP limitations for motorized cycles, mopeds, and motorcycles, all three of which require license and registration and insurance, but if you are below those limits, and don't go faster than 20MPH, with functional pedals, you are a bicycle and don't require any of those things. (it's more specific than that, but you get the general idea). 

Given that the tickets for not having license, registration, insurance, etc, could be really really expensive, in the four-digit range depending on what else they throw at you, you would be wise to be sure you don't build something that can't be legally defined as a bicycle in your area, unless you are going to build it as whatever other vehicle it would be defined as and do whatever other things the law requires of it.  

(There are bicyclists here in AZ and elsewhere who have had this problem DESPITE being within the legal limitations, and been unable to convince the courts that they are riding a bicycle, so being outside the limitations won't help any!)

I'll look for your other thread, too.




> Now back to business, I have some questions that are probably fairly easy for you to answer but I haven't a clue. Is it possible to wire let's say, 3 identical smaller controllers (maybe around 40 amps continuous) in parallel with each other and then hook up all the potentiometer wires of those controllers to a single potentiometer, and then wire all the outputs to a single wire that goes into the motor? Just a thought but with my limited knowledge it seems possible!


Technically, yes. Practically, it might get more complicated, depending on how they read that pot, and how they drive the motor. If all of the controllers can be throttled by a voltage level input as well as a pot reading (like most of 4QD's, and many ebike controllers) then you could use a hall-effect throttle instead of a pot. Those are pretty cheap in twist-grip form, for instance on http://electricscooterparts.com (which I only link to because I've seen them there, not because I would recommend them--I know nothing about them other than that their pages make a handy reference tool with pictures  ).

Tying all the MOSFET outputs on the controllers together to one motor might be more complex, and/or dangerous to the electronics.

It is much simpler to use a single controller that was originally designed for lower power, and parallel a whole bunch of identical MOSFETs on an external heatsink (replacing the ones that were built-in), than it might be to wire up several controllers like that. 



> On a side note, I thought it was pretty cool that I actually stumbled upon your "electricle" page earlier today when I was trying to look for others who had built electric bicycles. Cool work!


Nice to know it shows up in searches.  The current one is also on EValbum, number 2691. Funny that you should run into it earlier today, then have me answer your question here.  Small world!

I've been trying to find a good reliable SIMPLE solution that also meets certain other criteria for a couple of years, and it seems that often enough a solution that fits most of them will fail one of the major ones. Usually the simplicity one, but sometimes the reliable one. 

I'd say the very simplest one that worked pretty well (because it's usually dry here) was the pancake style radiator fan motors with roller skate wheels bolted to their hubs, driving the rear tire via friction. I think if I still had any batteries that would drive the motor, I'd still be using that on the upright bike. (there's no way I'm carrying three U1 sized batteries on that bike!)

Depending on your plans and your vehicle, you might want to read thru the blog to see what NOT to do. It may be more useful in that respect than in the what TO do, simply because most things I do on it are made of whatever parts I happen to have, and that doesn't always work out. 
________
Eve


----------



## ithinkidontknow (May 14, 2009)

Amberwolf said:


> FWIW, if you paid that much for it, someone else probably will, too. Just be honest about exactly what it is, and take a good clear photo of it's label (in sections if you have to), for them to see the specs for themselves.


I am having trouble telling because the seller said the motor is completely new and unused. Motors similar to this sell at golfcart stores for $500-700! I might have to do more research as I am still trying to find a spec sheet for this motor but I don't think I got ripped off too badly if at all. 


Amberwolf said:


> If you're willing to void the warranty on whatever controller you buy, you can also change the MOSFETs on it for larger ones, or simply parallel a lot of the same MOSFETs already on it onto a large heatsink panel. That doesn't take much electronics skill to do, and there are a bunch of project sites I've run across where people did similar things with pictures and some instructions.


This seems like an interesting idea as I could probably buy a cheapo controller and put some fat MOSFETs inside and from the sounds of it just might work!


Amberwolf said:


> Where do you live? I ask because different states have different restrictions on what a bicycle helper motor can be, power wise, and how fast you can go. Here in AZ, there's no specific definition for electric ones (just gas motor displacement limits), but there are HP limitations for motorized cycles, mopeds, and motorcycles, all three of which require license and registration and insurance, but if you are below those limits, and don't go faster than 20MPH, with functional pedals, you are a bicycle and don't require any of those things. (it's more specific than that, but you get the general idea).


I am having trouble finding these laws online so it might be easier for me to find someone who is in the know for this. I live in Washington State (Seattle area) and I think the laws are similar to those in AZ. I have also heard that the 20mph limit is a federally mandated law. Anyway, I think I will end up building it to go about 30mph and see if I can find a way to insure it and get a small license or whatever they need for me to drive it around! If I have too much trouble doing that, I'll just get a bigger sprocket or something and gear it so the max is 20mph. The plan right now is to make it so that there is no pedaling but I might rig up something later where I pedal to spin an alternator and charge the batteries. 


Amberwolf said:


> Technically, yes. Practically, it might get more complicated, depending on how they read that pot, and how they drive the motor. If all of the controllers can be throttled by a voltage level input as well as a pot reading (like most of 4QD's, and many ebike controllers) then you could use a hall-effect throttle instead of a pot. Those are pretty cheap in twist-grip form


I was actually looking at this controller from an EV company in Washington: http://www.evparts.com/prod-CT5310.htm
It also has a twist grip throttle that is made especially for it:
http://www.evparts.com/prod-PB5225.htm
I was planning to wire these in parallel and then get a 3:1 cable for plugs that go from the controller the throttle. Sounds like this would be the easiest to set up and test but maybe that's just my inexperience talking. Right now this is my favorite of the options because of simplicity. 


Amberwolf said:


> Tying all the MOSFET outputs on the controllers together to one motor might be more complex, and/or dangerous to the electronics.


Out of all the options, this one seems the toughest but that could also just because I have no experience with electronics. I also feel like I would have the most trouble setting this up. However, I am sure if I researched a little bit more then it would be doable.



Amberwolf said:


> Depending on your plans and your vehicle, you might want to read thru the blog to see what NOT to do. It may be more useful in that respect than in the what TO do, simply because most things I do on it are made of whatever parts I happen to have, and that doesn't always work out.


I will definitely go back through your website and read a little more closely. From what I've seen there seems to be some pretty creative solutions!


----------



## frodus (Apr 12, 2008)

Amberwolf said:


> Tying all the MOSFET outputs on the controllers together to one motor might be more complex, and/or dangerous to the electronics.


DO NOT parallel controller outputs. Actually it is dangerous for the controller. The Mosfets have to gate at exactly the same time in order for it to work. It won't work and you'll be very likely to let out white smoke.

I'd still keep looking online for a controller that is made for this type of motor or at the very least made for PMDC. I see them all the time for under $200. If thats too much then maybe you should reconsider your budget a little. I'd honestly look for a sepex controller and do it right. Otherwise you DO have to control the field current.

BTW, what IS your budget.... because you'll be spending more than $400 on the rest of what you need... Contactor...cables.... fuses....maybe a DC-DC converter (cheap 12V bat works too)..... chargers....throttle pot.

That motor should be fine, 2.5HP is continuous, it'l do more than that peak, but not with that little controller. 

1Hp = 745W, so to get 2.5HP, you'd need at least 1864W, and even then, its not likely going to move that little vehicle and you around very well, or at least not very fast. I'd think you need double that power to be happy with a 200lb vehicle + rider.

I'd start looking for something that'd do 24V and a couple hundred amps.


----------



## Amberwolf (May 29, 2009)

ithinkidontknow said:


> I am having trouble telling because the seller said the motor is completely new and unused. Motors similar to this sell at golfcart stores for $500-700! I might have to do more research as I am still trying to find a spec sheet for this motor but I don't think I got ripped off too badly if at all.


I suspect you got a good deal, as long as you don't *require* a PMDC motor. The good thing is that a motor like that can be used with AC *or* DC, so it's actually better for some applications, but since it "wastes" power for the field winding that a magnet would prevent, it *is* going to use more power that you might not want to spare on a very small EV.




> This seems like an interesting idea as I could probably buy a cheapo controller and put some fat MOSFETs inside and from the sounds of it just might work!


It should, in general. With my ex-Scoot'N'Go controller, since the entire drive section was burned out (literally), I first just took some MOSFETs off old Athlon motherboards, just to test the thing with the fan motors at 12V. It did work, but with a load on them, even with a really good heatsink with ~50 square inches of surface area on each side, and ventilation/airflow of the wind blowing past it as I rode the bike, it still blew them up due to (I think) noise spikes from the motor feedback. When they blew, that also took out the driving transistors, which were just 2n3906 & 2n2222 types. 

I fixed that by using 4-amp JFETs I had as the driving transistors, and those giant 123A 100V MOSFETs as the motor drivers, plus a beefy TO-style diode pair out of a PC power supply to help kill those spikes. No failures since then, no matter what motor I've driven with it, up to 36V. 

I'd go higher, but the controller electronics themselves probably couldn't handle it, so I'd need to do some extra wiring to get it to work with a 24V controller supply and then the MOSFETs and motor on the higher voltages. So far, no need. 

The powerchair motor I have is running on this setup, at 24V, and the heatsink barely gets warm most of the time (unless the bike is in direct sunlight, which is common here in AZ, because the sun will make the heatsink hotter than the MOSFETs will!).





> I am having trouble finding these laws online so it might be easier for me to find someone who is in the know for this. I live in Washington State (Seattle area) and I think the laws are similar to those in AZ.


They probably are similar. Your city codes are probably here at this site:
http://www.municode.com/Resources/code_list.asp?stateID=47

The state laws were quite easy to find, by googling "washington state bike laws". It's the first hit, and there are a lot of other good resources in the first page, too.




> I have also heard that the 20mph limit is a federally mandated law.


Not that I'm aware of; federal government doesn't regulate intrastate traffic law, only interstate traffic. There are recommendations in the Uniform Vehicle Code, but there is no requirement for any state to adopt anything from it (indeed, many never do).




> Anyway, I think I will end up building it to go about 30mph and see if I can find a way to insure it and get a small license or whatever they need for me to drive it around!


It might be a lot more complex than you imagine, depending on WA requirements for custom-built or modified vehicles. There are some states that don't like those at all, such as Ohio, and people have a really hard time ever getting those registered or allowed on the roads. There's even an ad here somewhere on the forum for a bike in Ohio (I think) that the person couldn't get them to register at all, so he's selling it since he can't use it. 




> If I have too much trouble doing that, I'll just get a bigger sprocket or something and gear it so the max is 20mph.


You don't have to change the gearing, but rather just ensure you never ride it faster than 20MPH, if the law there reads as it does here. 




> The plan right now is to make it so that there is no pedaling but I might rig up something later where I pedal to spin an alternator and charge the batteries.


That's going to be pretty inefficient, based on what I've seen (though I never built anything like it to test the theory--I'd've had to have the pedals switchable between the generator and the physical drivetrain on the same bike to test it out properly). You'll probably get more power out of your pedalling if you just directly channel it into the drivetrain, and use regen braking or similar (though doing that means you can't use a freewheel at the rear hub, meaning you can't use a standard bike hub and freewheel cassette, or a freehub and cassette; to get the shifting you'd have to use some internally-geared hub with no integrated freewheel I think). 




> I was actually looking at this controller from an EV company in Washington: http://www.evparts.com/prod-CT5310.htm
> It also has a twist grip throttle that is made especially for it:
> http://www.evparts.com/prod-PB5225.htm
> I was planning to wire these in parallel and then get a 3:1 cable for plugs that go from the controller the throttle. Sounds like this would be the easiest to set up and test but maybe that's just my inexperience talking. Right now this is my favorite of the options because of simplicity.


That throttle is one of the hall effect types (it's confusing that they put potentiometer in it's title, because it isn't one). So it will output a voltage that any controller can read, as long as that controller runs on the same voltage scale. 

One easy way to do this without dealing with wiring all the controller motor outputs together is if you use three of those other five motors you have, then wire a separate controller to each one. Just use one throttle input to all three, and they should run the same speed.

If the controllers have an offset control on their input as some of the 4QDs' do, then you can calibrate them all to run exactly the same from the single throttle input. Otherwise there will be slight differences, and the motors attached to each one will be at very slightly different speeds.





> Out of all the options, this one seems the toughest but that could also just because I have no experience with electronics. I also feel like I would have the most trouble setting this up. However, I am sure if I researched a little bit more then it would be doable.


Perhaps. Given my background and experiences I find replacing the MOSFETs with bigger ones to be easiest, but not everyone would. One must also be willing to deal with smoke and exploding electronics now and then when modifying motor controllers, as it does happen. 





> I will definitely go back through your website and read a little more closely. From what I've seen there seems to be some pretty creative solutions!


Given that I have so little income I can barely keep up with food/rent/utilities (sometimes not quite that), I have *had* to be creative with my solutions, since I can't buy anything yet. I'm hoping to fix that by working with someone else here in town soon that is interested in making some of my power-assisted trike ideas into reality for sale.
________
ROLL BLUNTS


----------



## SimonRafferty (Apr 13, 2009)

I've used lots of 4QD controllers over the years - and have always been impressed with how good they have been.

The most useful are the Uni and Pro series depending on your requirements.

If you want to get a bit more out of any controller, rather than replace the MOSFETS, or parallel more than one controller - connect a contactor to completely bypass the controller.

Use the controller to give you a gradual increase in power up to it's max - then close the contactor to give you a continuous rating at the max motor current.

When you slow down, do the reverse. On one vehicle I just used a microswitch which was pressed at the end of the throttle travel which gave it full power - a bit like a kick-down.

A big heat sink helps a lot too.

This uses a Uni 50A controller and this uses a Pro 120

Si


----------



## ithinkidontknow (May 14, 2009)

Amberwolf said:


> They probably are similar. Your city codes are probably here at this site:
> http://www.municode.com/Resources/code_list.asp?stateID=47
> 
> It might be a lot more complex than you imagine, depending on WA requirements for custom-built or modified vehicles. There are some states that don't like those at all, such as Ohio, and people have a really hard time ever getting those registered or allowed on the roads. There's even an ad here somewhere on the forum for a bike in Ohio (I think) that the person couldn't get them to register at all, so he's selling it since he can't use it.


So I looked through the vehicle section on this website and found that it may be easy to register this as a "motor-driven cycle". This is technically any motorcycle, scooter or other vehicle powered by a motor which is under 5 horsepower! This is exactly where my project fits in! Also, if I follow all of these rules and am able to do this, then I have no restrictions on maximum speed (other than the speed limit) as long as I can keep up with the speed of traffic! Seems almost perfect to me.
Here are some of the rules:
-No person shall operate a motorcycle or motor-driven cycle not equipped with mirrors on the left and right sides of the handlebars which shall be so located as to give the operator a complete view of the street or alley for a distance of at least two hundred (200) feet to the rear of the motorcycle or motor-driven cycle.
-No person shall operate a motorcycle or motor-driven cycle which does not have a windshield unless he wears glasses, goggles, or a face shield of a type approved by the State Commission on Equipment. (RCW 46.37.530(1)(b))
-Every motorcycle and every motor-driven cycle shall have its head and tail lamps lighted whenever such vehicle is in motion upon a street or alley. (RCW 46.37.020)
-Every motorcycle and every motor-driven cycle shall be equipped with at least one (1) and not more than two (2) headlamps which shall comply with the requirements and limitations of this chapter. (RCW 46.37.040(2))

This does not look too bad! The only problem I can see now would be to get something like this registered with the department of motor vehicles. I've heard good stories from insurance companies on these sort of things though.

Anyone from Washington have any idea what I can expect?


----------

