Can I run one throttle, one controller and two motors?

[Sangesf]

I have a dual (re: trike) setup and was wondering if I could use one controller for both wheels?
They are both rear drive and exactly the same..
(24v 450w - 20")

[albertlc]

hello! see here: http://goldenmotor.com/SMF/index.php?topic=2133.0

[Andrew]

I've read that article.

How easy would it be to connect up two MP's with internal controllers? 

[Leslie]

I have a dual (re: trike) setup and was wondering if I could use one controller for both wheels?
They are both rear drive and exactly the same..
(24v 450w - 20")

If you bolt two hubs together so each move together yes but you would need a bigger controller and maybe a dual pack to make it practical.


One hub at 30 amps should be as good as two hubs at 15 amps so you don't need to overload the battery.  The point of a dual MP set up is to have double the MP power not double the MP weight.

That said there is no reason why one cant have a dual pie with internal controllers on a single throttle and a dual pack.

One guy here runs dual Pie off a single 48v 12ah pack and says its cool.

[Sangesf]

I know I can hook up two motors (and controllers) to a single throttle.
I was wondering If I could do it with one controller. 
The controller is a 36v 40a controller in which I never go over 25a on one wheel.
I guess my question was a couple of questions in one.

1.) do the motors need to be physically (by axle) connected to each other?
If so, do they need to be run with or without sensorless control (on one or both)?
If not,  what's the best wY to accomplish it.

If they don need to be physically connected, c same sub questions..

[Dummy Dave]

I know I can hook up two motors (and controllers) to a single throttle.
I was wondering If I could do it with one controller. 
The controller is a 36v 40a controller in which I never go over 25a on one wheel.
I guess my question was a couple of questions in one.

1.) do the motors need to be physically (by axle) connected to each other?
If so, do they need to be run with or without sensorless control (on one or both)?
If not,  what's the best wY to accomplish it.

If they don need to be physically connected, c same sub questions..

I agree with Leslie.  Here's another way to see it:
Your problem is phase timing.  The controller needs to know when to power each phase of the motor.  If you have two motors on the same axle, they can only stay in sync if you never, ever turn from a perfectly straight line.  And that would only work if you somehow managed to get them both in exactly the same position before starting, and keep them that way (Leslie's bolting them together). 
Any turn at all and then you need two controllers.
The MP is handy for this because each has its own controller.
You can use the same throttle for both controllers, as Leslie said.

-David

[Leslie]

I was thinking more along the lines of a dual controller.


IMO the internal controller seem adequate to make the motor work and get people around but it is a little resistive off the mark.

Having a parrallel FET bridge will certainly take away some of the load voltage slew over the drain source legs.  Hook all the hall sensors in parallel.


One possible way to get them calibrated would be feed the negative rail via a single amp shunt to both controllers and see if the software can balance the load good enough to get the beneifits.

Fets and hall signal logic processors controlls and brake gate breaking drivers can exsist connected as parallel.

Maybe its not to get two Pies its more to get what one Pie can offer.

These are my findings.  The single with an internal controller MP is capable of delivering over 2000 watts but it's a tiny controller and not all those watts are used up in an area where the Pie stator could give better performance.

To make the thing pull off the mark in any decent manner I had to set the voltage setting to 24v and current to max. Still lucky to pull 23 amps and 17 cont.

Like before I installed the MOD the Pie was lucky to pull 3 amps from the throttle at stand still. As the bike moved slowly off the mark it gained more amps,  By the time I reached 12 kph the power would start kicking in.  I was getting 400 watts by about 12kph

After I installed an old 10 amp GM controller shunt in to my controller I saw a jump to 40 amps max and 24 amps cont so I set it back to 48v and now I get this.

At 48v software setting on a 48v pack.

I set constant to 13 amps I get 17 amps.
I set peak to 25 amps peak I get 23 amps.

Close enough.  Nearly 1200 watts

And its more like  6 amps from stand still and I am pushing 23 amps by about 7kph.  It still is sluggish on the 6 fet controller.  I want to push more volts into the motor coils, not have it drop away over the fets.

I take it for an efficiency test soon.

BTW all this time my regen has been disabled.  What I am looking for is confined amperage dynamics and good steady results in the max amps.

Playing around with all these settings may not be wise to use regen.  I am hoping my controllers will live through all this modding.  The CA is a very good tool to help me..

[Dummy Dave]

I was thinking more along the lines of a dual controller.

Sangesf was trying to run 2 motors from the same old-style single controller.
A dual controller would still need independent timing, because each phase of each motor needs its power at the best angle, and the wheels are always traveling different distances around corners.

I see where putting 2 controllers on the same board would let you play a little, but there's a lot of extra heat to dissipate, for a system that's already marginally heat-challenged. 

In an external box, with enough heat sink, if you really just want to design and experiment, sure... But why bother?  Is there that much to gain?

-David

[Leslie]

I was thinking more along the lines of a dual controller.

Sangesf was trying to run 2 motors from the same old-style single controller.
A dual controller would still need independent timing, because each phase of each motor needs its power at the best angle, and the wheels are always traveling different distances around corners.

I see where putting 2 controllers on the same board would let you play a little, but there's a lot of extra heat to dissipate, for a system that's already marginally heat-challenged. 

In an external box, with enough heat sink, if you really just want to design and experiment, sure... But why bother?  Is there that much to gain?

-David

I ment two controllers on a single motor, but yes the issue of corners and imbalanced left right motors still make life difficult.

I honestly don't like the idea of dual drives but it should be a requirement for some uses.

But whatb happens on such a trike when one wants to turn right but the right motor is giving most of the power?

Dual controllers are needed but an electronic differential system off a single throttle may be required.

Maybe a wheel chair controller and joy stick would serve better for such a design.

[Sangesf]

I guess I need to stick with two controllers....

I was wondering if I ran two of the Magic Pie's (without the internal controllers) on one Controller in sensorless mode  (I have a 36v 100ah LiFePo4 pack, I just built)

I know I can run two controllers in parallel (battery wise) with that setup, but was hoping to use one controller. 
If it's not (EASILY) possible, I'll just stick with two controllers.

[MonkeyMagic]

Hey Sangesf

Running 2 pies myself I would strongly recommend against going 2 x external controllers unless you want to overvolt or do something spectacular just stick with the internals.

There is enough cabling as it is! Plus it's nice to just link in the cruise control and e-brake etc.
I have my cabling quite neat and have contemplated going external for fun but it would get really messy.

Just an opinion but I would stick with the internals

[Bikemad]

Frank, you are not going to be able to run two Magic Pies on a bike from one controller, because there is no way that both motors can stay correctly synchronised with each other, unless they were physically joined together with their magnets (and stators) in identical positions, which would be a major feat in itself.

As the Magic Pie has 56 magnets (with the poles arranged North-South-North-South all the way around) each pole is sligthy less than 6.5 degrees from the next opposing pole. If one wheel were to vary by this amount in relation to the other, one of the motors would be trying to brake while the other was trying to accelerate and they would be fighting against each other, producing no useful forward propulsion at all.
So, if you think about the reality of both wheels staying precisely matched within fractions of a degree, you should be able to see that it is not a practical proposition.

If you're still intent on trying it out, I'd love to see a video of the test run.

I think it could all run relatively smoothly with both wheels in the air, but with both wheels firmly on the ground it would be a totally different matter.

Alan