# Ghetto controller?



## todayican (Jul 31, 2008)

OK, ive been looking around and cant find any good info on this..

I'm toying with the idea of using a 4.7 hp rated 12v winch motor to replace "first gear" on a trike im building.

The idea is to use as small as possible an ICE to keep the mpg real high.

Also, the goal is to build a 100mpg car with air conditioning and 2 seats for as little money as possible.

So here is the question: Ive seen "contractor" controllers where one forgoes the controller altogether and uses contractors only. how bad an idea is this? How would one build one? If one wanted to go slow could he not "feather" the on off button?

This might be completely hair brained, but I thought I would look into it 

Thanks!
Tom


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## peggus (Feb 18, 2008)

Well, the contractors may object to you running high currents through them, besides burning flesh smells really bad. 

You could use contactors instead, but smooth application of power would require multi-step contactor controller and golf cart controllers are so cheap on ebay I doubt you'd save anything.


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## todayican (Jul 31, 2008)

lol, good catch  (although I CAN think of a few contractors whod have it coming to tham...)


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## Woodsmith (Jun 5, 2008)

todayican said:


> If one wanted to go slow could he not "feather" the on off button?
> Thanks!
> Tom


Doing that would work for a while but you would need to be cycling the contactor on and off at a fairly fast rate, a sort of human-mechanical PWM.
It will object a little each time it has to make or break full load current and will only be able to do this so many times before it fails.

You might find that having a set number of fixed steps switching the pack in various arrangements of parallel and series connections would give you a usable stepped controller without cycling the contactors as much.


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## Jimdear2 (Oct 12, 2008)

Let me see if I understand this, you want to use an electric motor to JUST get the vehicle moving so that the "just right" (too small) sized ICE can then accellerate the vehicle to your chosen cruise speed without having to overcome inertia from a dead stop? I assume that the electric will be shut off as soon as the ICE can take up the load?

Since the average used low gear speed of most vehicles is under 10MPH the single contactor should work fine as long as your battery is up to the starting surge amprage draw. What I believe will happen, is you'll draw big amps with a low sagged voltage (lots of torque). This will start you off, then as the vehicle comes up to final speed, amps drop and voltage (speed) rises until the ICE takes over and you shut off the electric motor. Acts kind of like an electric variable speed transmission.

My opinion is that any mpg gain in using a smaller engine would be lost in the hauling around the additional weight of the electric motor, controls and large battery. 

What happens when the battery goes low or dead?

Jim


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## Tesseract (Sep 27, 2008)

You can do this, sure... whether it is reasonable, much less economical, is a different question altogether.

You still need a freewheeling diode and you will almost certainly need to add a substantial amount of inductance in series with the motor to make up for the vastly lower switching frequency achievable with a contactor controller. You still want to make throttle proportional to amps, so that's a current sensor and PWM generator. All in all, perfectly reasonable. 

Now the bad news... I don't recall the exact numbers, but I already worked out a similar problem when the "mechanical PWM" madness was all the rage here awhile back... Using an Albright SW200 contactorI think I determined that the max switching frequency was under 100Hz and that the contactor would survive a few hundred seconds of operation. Contactor PWM controllers are, in a word, expensive.


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## todayican (Jul 31, 2008)

The way I look at it, is if I use a motorcycle engine, I would need to add some sort of electric reverse anyway so...

If my math is right, the winch motor is about 18lb 24v worth of 60a thunderskys 42lbs. controller and hardware, say 10 lbs

70 lbs altogether. (probably 40 of it would need to be present one way or the other with electric reverse)

I can also tap the batts in parallel for accessory power.

If this makes the difference between using a 250cc engine and a 500cc engine, im getting a 30 pound lighter ICE 

The real trick at the moment is to figure out how to move the Wibch motor into and out of the drive stream, (if it stayed engaged, it would over rev when the main drive line surpassed its ability to keep up


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## Jimdear2 (Oct 12, 2008)

todayican said:


> The way I look at it, is if I use a motorcycle engine, I would need to add some sort of electric reverse anyway so...
> 
> The real trick at the moment is to figure out how to move the Wibch motor into and out of the drive stream, (if it stayed engaged, it would over rev when the main drive line surpassed its ability to keep up


Simplest method I can think of is an electric clutch and sprocket, running against the drive chain to the rear wheel. The electric clutch could be hooked in parallel with the neutral light of the motorcycle engine. Neutral light on, electric clutch can engage. Neutral light off clutch cannot engauge.

Jim


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## todayican (Jul 31, 2008)

Cool idea but...

Perhaps im wrong but with the second sprocket "laying on top of" the main drive chain, im concerned that it wont have enough teeth in the chain to grip right?


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## Woodsmith (Jun 5, 2008)

todayican said:


> Cool idea but...
> 
> Perhaps im wrong but with the second sprocket "laying on top of" the main drive chain, im concerned that it wont have enough teeth in the chain to grip right?


If you look at the electric reverse gear used on some motorbike trike conversions they do a very similar thing. The motor and sprocket is simply lowered onto the chain by a lever and it then drives the chain backwards. You are doing the same thing but driving both directions.
Jim's idea of the electric clutch is good. You can get one from an AC compressor and see if it is up to the task.
If not you can use a simple lever to raise and lower the sprocket into engagement.


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## todayican (Jul 31, 2008)

Great! do you happen to have any links for such a setup, Ive looked but so far have only seen trikes where the electric motor goes into a diff or something.

If that would work, this would be super simple to fab.

Here is another thing, say the winch were to be "good enough" at only 12v to replace 1st gear up to say 12 or 15mph, what would a 12v "controller" look like? would it be any easier, safer to build?

Any devices out there that use variable speed on 12v high power devices? I looked around for variable speed winches for example, but no luck


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## Woodsmith (Jun 5, 2008)

You might also find it useful to look at companies that supply modified winch motors for off road winching competitions.
Goodwinch is one company I am familiar with in the UK. 
Scroll down the index and have a look at their Bowmotors. Companies like them may be able to help you with the specification and performance of their motors to give you an idea if it would even achieve what you want.
Bear in mind that at 12v they can draw 400+amps but there are 24v versions.


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## Jimdear2 (Oct 12, 2008)

todayican said:


> Great! do you happen to have any links for such a setup, Ive looked but so far have only seen trikes where the electric motor goes into a diff or something.


Sorry no links, these are just off the top ideas



todayican said:


> If that would work, this would be super simple to fab.


As far as chain wrap a little fiddleing could give you a motor that was also a spring loaded chain tensioner. Or you could build a double sprocket for the motor, one sprocket and chain to the rear wheel and one to the electric motor



todayican said:


> Here is another thing, say the winch were to be "good enough" at only 12v to replace 1st gear up to say 12 or 15mph, what would a 12v "controller" look like? would it be any easier, safer to build
> 
> Any devices out there that use variable speed on 12v high power devices? I looked around for variable speed winches for example, but no luck


Since you plan to use this as a low gear as well as reverse, you should look for a small controller. I believe I have seen some in the 100 amp 12/24 volt range. I think Curtis makes some. A PWM controller would make the motor speed control and reversing much smoother. Even if you couldn't find a 12 volt controller 24 volt controllers ARE available and cheap.


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## Woodsmith (Jun 5, 2008)

The very small controllers may not have the current capacity for the power that a winch motor can produce. Some are rated up to 5 or 6hp at 12v, that would be around 370A.

You would need to calculate the power required to do what you want to see if a small 100A controller would do it.


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## todayican (Jul 31, 2008)

Thanks Guys! Competitive winching, whoda thunk it?


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## todayican (Jul 31, 2008)

I could possibly go with an iskra 24 from this page; http://www.dborc.co.uk/goodwinch/

and an alltrax axe 4834 (which im told can go down to 24v) for like 300 bucks

and run it like that or...

sneak it up to 36v or possibly even 48 (with 24v the iskra turns 2800, I wonder how the bearings would like 5600?)


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## Woodsmith (Jun 5, 2008)

todayican said:


> Thanks Guys! Competitive winching, whoda thunk it?







Also use twin motors.









And siamesed motors.


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## Woodsmith (Jun 5, 2008)

todayican said:


> I could possibly go with an iskra 24 from this page; http://www.dborc.co.uk/goodwinch/
> 
> and an alltrax axe 4834 (which im told can go down to 24v) for like 300 bucks
> 
> ...


I would say contact David Bower and see what he has to say about it. Do it by email though, he is a bit of a talker when he gets going.


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## nimblemotors (Oct 1, 2010)

I have one of these winch motors. 
Step 1 was to find a coupling for the unusual 20-spline shaft!
I've ordered a coupler from Warn, hopefully it will work, have to wait and see. 

My thoughts where to maybe use it for my MGeo 1.0L hybrid as a motor assist, similiar to what you have described. It would also be the starter motor for the engine, so it doesn't really add any weight.
It would couple directly to the front of the crankshaft, the rotor can just spin with the engine, these can spin at 3000rpm no problem.
Also thought I might use it for a reverse motor for my secret 3-wheel project, which would remove the need for a shift to reverse in the transmission, and heck maybe add some more forward power.
These are just ideas at present.

Winch and Starters are series motors, normally just use on/off solenoids and draw as much current from the 12v battery as possible or needed for the load. At stall they will go infinite current and melt. I don't think this type of on/off control would work too well, just asking for trouble. 
I'd use a higher voltage pack (e.g. 48v) and a standard motor controller,
they are pretty cheap now a 48v 300amp unit is $300 ?

I built an Electric outboard for my sailboat, and used a 2.5hp 12v pump motor, and created a DIY 48v controller for it, that would forward or reverse. It would draw max 100-150amps at 48v = 9.6HP. Eventually the motor would get pretty hot at full throttle (and my controller too, had to add water cooling to it) I suspect I can run these winch motors at 48v 300 amps = 20hp for a short time.


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## todayican (Jul 31, 2008)

Good input Nimble, Thanks
BTW If you wanna let me in on your secret trike project, I might can lend a hand 

So your of the opinion that with decent air cooling, up to 10 min of 48v x 300 amps would be ok?


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## nimblemotors (Oct 1, 2010)

todayican said:


> Good input Nimble, Thanks
> BTW If you wanna let me in on your secret trike project, I might can lend a hand
> 
> So your of the opinion that with decent air cooling, up to 10 min of 48v x 300 amps would be ok?


I'm not sure it would hold-up to a 10 minutes at full 20hp like that.
Maybe once, then 4 hours to cool back down!
For a hybrid assist, 1 minute is a long time. And for reverse you wouldn't need full power. Frankly, these are cheap enough that you could use two or three or even four if you really needed to if one won't cut it, at $75 each, four of them is only $300 !!


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