hi everybody:) dc brushed hub motor vibrates. stutters

S

sanael2012

1 mW
Joined
May 6, 2012
Messages
13
New guy hopefully you wont mind weird questions from time to time

So. Recently i got an OLD and very heavy e-bike from a friend. It was hybrid and
Used an old dc 2 wire (red & black) i guess brushed hub motor, i tore it all apart
since everything was glued together panels and all... I found a controller inside
That was impossble to get to... It had a blown fuse which i replaced...
The controller has what seems to be a hall sensor on a short cable that reaches the pedals
Which are all bent by the way... They seem old and burnt wont work.
I tried connecting 12v dc and the motor Started spinning so i figured it would work with 36v sla 7ah battery pack
I made a on/off switch and ran thick cables to the steering rod and back
I tried it and it worked... I pedal at first and then turn it on.... I get up to 18km/h
On fully charged cells for 15minutes on flat ground...
I connected.the controller in parallel with the connwction i made so i can
See battery leds and use the headlight.... so here my are my questions

I know this is brute but how can this hurt the motor...

Also the motor makes.a.stuttering sounds like an otter hehehe
f i kick the pedal a little bit or sometimes flip the switch slowly it gets
stronger and faster... And stops stuttering... But the powe leds say shorting out
And power is minimal.

I think its cuz the bike is too heavy and so am i... Total load is 165kilos
?
What can i doi to get more speed amd torque... 48v? Can it die from higher v?

owcan i use the controller with on off switch without hall sensors

Can i make a battery pack with 3x 12v 7ah and 6x 6v 7ah so building a 36v from 12v batteries i series and
12v from
 
New guy hopefully you wont mind weird questions from time to time

So. Recently i got an OLD and very heavy e-bike from a friend. It was hybrid and
Used an old dc 2 wire (red & black) i guess brushed hub motor, i tore it all apart
since everything was glued together panels and all... I found a controller inside
That was impossble to get to... It had a blown fuse which i replaced...
The controller has what seems to be a hall sensor on a short cable that reaches the pedals
Which are all bent by the way... They seem old and burnt wont work.
I tried connecting 12v dc and the motor Started spinning so i figured it would work with 36v sla 7ah battery pack
I made a on/off switch and ran thick cables to the steering rod and back
I tried it and it worked... I pedal at first and then turn it on.... I get up to 18km/h
On fully charged cells for 15minutes on flat ground...
I connected.the controller in parallel with the connwction i made so i can
See battery leds and use the headlight.... so here my are my questions

I know this is brute but how can this hurt the motor...

Also the motor makes.a.stuttering sounds like an otter hehehe
f i kick the pedal a little bit or sometimes flip the switch slowly it gets
stronger and faster... And stops stuttering... But the powe leds say shorting out
And power is minimal.

I think its cuz the bike is too heavy and so am i... Total load is 165kilos
?
What can i doi to get more speed amd torque... 48v? Can it die from higher v?

owcan i use the controller with on off switch without hall sensors

Can i make a battery pack with 3x 12v 7ah and 6x 6v 7ah so building a 36v from 12v batteries i series and
12v from
 
Boo boo post
 
Stuttering is usually seen with brushless motors, so I can't say what's causing it in this case.

Runs fine with the battery hooked straight to the motor correct?

What you need is a new brushed motor controller and new throttle. The straight hotwire trick will result in your switch welding itself into the on position. Then you get to throw the bike and try to run that fast. Hope you got dental insurance.

Once you have a fairly cheap new brushed controller and matching throttle, you will get rid of all that original wiring. Some throttles have a battery level indicator, so you can keep that. Or get a voltmeter to indicate battery level.

Don't wast money on it though, if your motor won't run smooth on 12v.
 
Yeah, if it doesn't run smooth on 12v, it would be something like that. Sometimes brushes on old stuff get crusty, and run better when they rub off some dirt or whatever. The brushed hubs do throw a magnet too, but generally lots of scrapy noises from that rather than a stutter.
 
The hotwire trick as you put it works well... I have a heavy duty switch and a kill switch right beside it...

Brushes might be broken was my thought too... I tried opening the hub but the metal star that connects to the chain

With the chain wont come off... I need some special too
 
If the motor spins correctly with battery directly hooked up to it, clearly it's something in between that is broken like the throttle or the controller.
 
Ok listen the hub motor runs well with direct connect with no throttle only heavy on off switch with a heavier killswitch.... no controller no throttle.... I think its the switch that gives too sharp of a current when flipped on.
Causing something to slightly move and this could make it stutter... If i flip the switch very slowly it sparks and the motor starts and doesnt stutter....

I think there might be gunk on the brushes too... I have never heard of a 2 wire brushless

What can i out in between the switch and the motor so the voltage and current rises slowly?
 
Nah, you need a new controller and throttle. Pretty cheap in the USA, for fairly low power brushed controllers.
 
I had the same issue on a 36v brushed DC motor. Fixed by changing yellow blade connectors for new. Blades had black pitting, 3 months old. I think bad contact chokes the voltage, then full contact. TNC confirmed controller or throttle does not do that.

I've have blades burnt to a sliver on 24v bike, worked under power, did not work after stopping. Broke the arch at stop I guess. This was the first bike learning curve, old batteries, 2 miles to the charge, who cares how fast..look maw I ain't peddlin'.

So go over all connectors in the power side, to be sure <edited a missed word> solder temporary jumper wires a couple of inches each side of any connectors if you are afraid to screw up connector <edited another missed word> or have a cost concern. Its between battery to controller & control to motor.

Another thought is a switch in between battery & controller. I've had a low amp key switch located at steer tube, with 36v from battery going thru it when it should have been 5v. So trace positive battery side with your meter, see whats in the circuit.

Wornout brushes don't stutter, goes real slow until you stop the throttle, then no go. Only happened to me once, so others may have a different experience.

Changing out controller may work because you reseated the connectors, nothing wrong with it.

Don't meter controllers & throttles, ONLY test for output voltages. Heres how,
Controller: disconnect motor & connect V meter to these 2 leads, twist throttle. Slow steady increase, reads 0 to battery voltage. Spikes?, replace throttle.
Throttle: meter to find signal wire. There are three wires in the throttle circuit, (other wires if you have LED's or thumb switches in the housing) Red is 5v positive, test this, meter connected & neg lead to battery negative terminal. Don't trust colors EVER, always prove. Same thing, identify ground to battery. The 3rd is often green, 0.0v stopped & increases smoothly on throttle twist to 5v. Never exact as I have seen 3v & bike worked. Seen 6v something too.
Brushed motor: Disconnect all wires, connect meter the 2 thickest & move motor slowly FORWARD. Slight voltage as low as 0.4v ?, the motor works. Move wheel faster & voltage increases. Spin & you might see 2 volts.
I hope I did not miss anything. <third edit><some dumb typing tonight & thats one fingered>

Hope you are already solved.
 
Thanx dude... I didnt think of metering the wiring hehe

What is a blade connector?

I live in sweden so i dont have access to cheap controllers and throttle
I do however collect electronic junk and can probably find the parts for a simple
Throttle and controller . My friend is good at soldering and i got the parts... All i need is
Good schematic for a simple controller and throttle
 
Sweden? My great grand daddy came from there, jumped ship in NY harbour in 1896. No money for passage I guess.

Blade connectors are found in after market auto parts stores & auto electric repair shops. You get motor brushes at the same shops. There is 3 sizes I know of, blue, red & yellow is the largest, crimp hole accepts 10 gauge wire.

You don't have "yellow blades" on your bike, you don't need them, you don't want them for permanent repair. My reference has to do with failure, why your motor stutters. AS I pointed out, you have contact failure somewhere in the power wiring, review what was stated. I also listed repair testing proceedure for brushed DC motors & its components. Prove they are good FIRST.

When you have problems with brushed systems, check the components, doesn't take long or cost you like parts changing does. If the parts are OK, then it has to be in the wiring, that takes time, as you won't find it with metering voltage or continuity. You cannot use an ohm meter, it may damage the electronics. You can do this if the controller & throttle is disconnected, but doesn't prove your issues as you can have voltage but not enough contact for the amps/current needed for the power under load, such as 20 KPH.

Contact failure can be in hidden "twisted wire" repair, soldered wires (?), fusing & battery contacts. If this is a used bike, chances are good someone has messed with the wiring & taped over the "repair". This can be wires getting cut as in remove insulation for a meter connection, but cut thru some wire strands.
 
really, i double down on this. if it is used, assume the reason it is sold is because some idiot tried to repair it before and broke something, different from what put it outa commission originally, so you may even have multiple mechanic induced failures. they never admit it either, you only find out later when you have to take it apart to fix it.

like he said, take the time to examine the wires for continuity or shorting problems, corrosion in contacts.

my toaster quit, would not heat up, i opened it up and found a spider had laid her egg nest right on the contact where the power switched. so no metal to metal contact because the wiper would ride up onto the egg bundle, no toast!
 
Poor little spider babies... You didnt kill the mother too did you?

Anyway i made a battery pack enclosure out of a hard plastic travel container
I think it was for makeup n shit.. It had a mirror in it... It has a lock and handle like a toolkit
i think will hold for rain. I soldered everything and used heavier connectors for battery
I put a watertight heavy duty switch on top of the pack
I put a eu wall outlet socket on the side need to make it.watertight
Im gonna use epoxy or universal glue

I used the wall plug from an extender chord and the cable from the same for the rest

I am going to solder all the rest today

What am i looking for in dc current and voltage ? How much loss is acceptable.

If the voltage is 13.3on 2 batteries and one is 12 is that a problem? How do i balance them?

I have a old broken multimeter with a non digital meter... How do i make it show me current?
 
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