Carrera Vulcan hacks..

Fat Rat

Esteemed Pedelecer
Jun 7, 2018
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UK
Hi welcome
Try the speed pedelec part of the site
 

anon4

Esteemed Pedelecer
May 9, 2017
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Anyone know of a speed hack for the Vulcan ,would appreciate any info,thanks..
You need a new controller. Under the battery is a box, open it you will find a box with wires coming from it to the motor, sensors display etc. You have to cut the wires and add crimps or solder directly to a new controller. Then you have to change to a compatible display, pedal sensor, and throttle if required. This will get you to about 20mph. I then changed my battery to 48v and this will get around 25mph, beware though as I am plagued with issues since upping the power, not sure what the cause is though.
 

anon4

Esteemed Pedelecer
May 9, 2017
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Can we have details?
Mainly that the motor cuts from a standstill. Reducing current on the controller stops this, been chatting it over on endless sphere the verdict there is an intermittent motor short that the multimeter can't seem to pick up. So it's either strip the motor down or wait for it to get worse I guess. This may or may not be related to the power upgrade but I did have some connectors melt because of this that shorted out. This probably did some damage
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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Intermittent motor short? Who came up with that? You have to be careful on ES. There are some very knowledgeable guys and there are some that probably mean well, but just spout rubbish. They've never used a KT controller and have no idea about settings.
 

anon4

Esteemed Pedelecer
May 9, 2017
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Intermittent motor short? Who came up with that? You have to be careful on ES. There are some very knowledgeable guys and there are some that probably mean well, but just spout rubbish. They've never used a KT controller and have no idea about settings.
I don't know, but I measured the phase wires again today, I discovered the resistance jumps around if I move the wire at all. On closer inspection it looks like the wire got pinched a little, this could be the culprit. The insulation on the phase wires is rubbish so it's fairly possible that it is damaged. Intermittent because they could be not quite touching but enough current causes an arc. I tested the battery and that doesn't appear to sag much when it happens, wheel doesn't stick when turned.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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What are you measuring the resistance with and how are you attaching it? The resistance of the coils is very low, so there's a fair chance that you're measuring contact resistance.

If there was really a short, your motor would be cutting every time you went over a bump, not just when it's trying to start.

Can your controller run in sensorless mode? Does it have auto-detection of hall sensors?

https://www.aliexpress.com/i/32821323996.html
 

anon4

Esteemed Pedelecer
May 9, 2017
515
77
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GB
What are you measuring the resistance with and how are you attaching it? The resistance of the coils is very low, so there's a fair chance that you're measuring contact resistance.

If there was really a short, your motor would be cutting every time you went over a bump, not just when it's trying to start.

Can your controller run in sensorless mode? Does it have auto-detection of hall sensors?

https://www.aliexpress.com/i/32821323996.html
Mines sensor only I believe. I was using probes in the motor plug, between each 2 phases they measure between 0.4 - 0.7 ohm, if I wiggle the wire this can jump to over 2 ohms. I suppose it's not the most reliable test, I'm at my wit's end with it. I get what you're saying that it would cut on bumps too, it did cut power altogether last night over a big bump but I'd left my battery unlocked so it probably jumped slightly out the cradle breaking contact. Controller doesn't have "self learn" if that's what you mean, but my old one did and that suffered random cutouts of a similar nature. I believe it all started when the one before these two shorted at the shunt, have I damaged something?
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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Some KT controllers are dual mode, likethe one in the link. They have automatic detection of the halls and will switch to sensorless if they don't detect them. That would cause starting problems.

Did you try different P1 settings?
 

anon4

Esteemed Pedelecer
May 9, 2017
515
77
27
GB
Some KT controllers are dual mode, likethe one in the link. They have automatic detection of the halls and will switch to sensorless if they don't detect them. That would cause starting problems.

Did you try different P1 settings?
The description says it must have sensor, this is the model

£18.57 | 36V/48V 500W Brushless DC Sine Wave sensor Controller ebike Electric Bicycle Hub Motor Controller with right output
https://s.click.aliexpress.com/e/bgBuptJE

I tried a lot of P1 settings and settled on 100 which seems to be right for this motor, anything else doesn't run as smooth
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
1,427
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Basildon
My next step would be to lookat all the connections where you joined the motor cable to the controller. Maybe a dry joint or something like that.
 

anon4

Esteemed Pedelecer
May 9, 2017
515
77
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GB
My next step would be to lookat all the connections where you joined the motor cable to the controller. Maybe a dry joint or something like that.
They are all solid, I made sure of it when I ditched the connectors. I have an in line plug further down, any way to test if that's bad?
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
1,427
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Wiggle it?

Another thought. Does the motor have the same cutouts with the throttle and the pedal sensor?
 

anon4

Esteemed Pedelecer
May 9, 2017
515
77
27
GB
Wiggle it?

Another thought. Does the motor have the same cutouts with the throttle and the pedal sensor?
Throttle does it worse but its present on both. Connector seems solid but can't see where the wire joins without butchering it I guess
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
1,427
245
Basildon
Your problem is not an easy one. I think it's more likely a settings issue than anything else, but you have to consider that not all controllers are compatible with all motors. It would be nice to test it with one of the old KU63 controllers that would work with anything.

One thing you could try is to put a nice big capacitor across the battery wires to provide a bit more oomph to the battery for the pulsing you get at low speed.
 

anon4

Esteemed Pedelecer
May 9, 2017
515
77
27
GB
Your problem is not an easy one. I think it's more likely a settings issue than anything else, but you have to consider that not all controllers are compatible with all motors. It would be nice to test it with one of the old KU63 controllers that would work with anything.

One thing you could try is to put a nice big capacitor across the battery wires to provide a bit more oomph to the battery for the pulsing you get at low speed.
Which settings? I already changed the battery wires to a heavier guage which changed nothing. The seller rates the battery at 25a continuous, 50a pulse, nothing fancy should be needed unless a connection is sucky or they have grossly overrated it.
 

anon4

Esteemed Pedelecer
May 9, 2017
515
77
27
GB
Your problem is not an easy one. I think it's more likely a settings issue than anything else, but you have to consider that not all controllers are compatible with all motors. It would be nice to test it with one of the old KU63 controllers that would work with anything.

One thing you could try is to put a nice big capacitor across the battery wires to provide a bit more oomph to the battery for the pulsing you get at low speed.
I have since asked the manufacturer what is going on after determining that there is no physical fault anywhere on the bike. They have said that the current is higher than the controllers limit on startup so it cuts power to the motor. They recommended reducing current via C5 which I have already been doing as a workaround, or to ramp the throttle gently which is difficult with a thumb throttle. This seems like a design flaw if what they say is true, yes the controller should limit current to keep things working but not by just shutting down the motor. I would happily use it reduced but I have felt the full power it's capable of and I'm definitely missing out on some ooomph, I don't see any way to configure it so I can make it startup gently without reducing its capabilities, so perhaps the only way is to get a slighter higher rated controller that has the headroom to run 20a without getting overworked
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
1,427
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I've used a lot of KT controllers, some with shunt mods to get extra current. I never experienced that problem, and I can't see how it can happen. The MOSFETs are like taps, they ony open and let the battery power through. If you set the current too high, they get hot and blow. Only the battery can cut the power. If the controller allows more current than what the battery can provide, you'll get cut-outs. That's why I suggested a big capacitor to boost the current.
 
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anon4

Esteemed Pedelecer
May 9, 2017
515
77
27
GB
I've used a lot of KT controllers, some with shunt mods to get extra current. I never experienced that problem, and I can't see how it can happen. The MOSFETs are like taps, they ony open and let the battery power through. If you set the current too high, they get hot and blow. Only the battery can cut the power. If the controller allows more current than what the battery can provide, you'll get cut-outs. That's why I suggested a big capacitor to boost the current.
I had a feeling they were talking a load of crap, not sure why when it's their own product. How would I install a capacitor? I still think the battery should be able to cope without mods unless of course it's faulty, I've seen many bikes with BIG motors using similar Chinese cells and KT controllers and while they don't get much in terms of range they at least work. My gut still says something is foul. The battery barely sags when a cutout is reproduced, when full it shows 54.2v and it will drop to 51.09v, I've seen worse than that on a cold day without issues. Still I will try the capacitor if you think it will help, anything is worth a go at this point. At 15a the thing feels anaemic, can barely fight the wind
 

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