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yiyun controller going full voltage to motor with no input

Posted: Fri Nov 10, 2017 7:41 pm
by Quinc
This is my third yk31c controller and the first time I have ever had an issue.

Been riding the razor for two days and today all of a sudden it went full voltage to motor as soon as i turned it on. Had to pull a cable off a battery to get it to stop. to troubleshoot I unhooked everything but the motor and batteries and it still goes full throttle. I pulled the controller apart and there is no black/fried spots or smells. :?:

500w unite motor
36v 10ah batteries
12ga wiring

Re: yiyun controller going full voltage to motor with no input

Posted: Fri Nov 10, 2017 9:15 pm
by zogthegreat
Try checking the capacitors in the controller and see if any of them are leaking or bulging. The Chinese controllers use the cheapest caps as possible. They are usually made of aluminum instead of copper.

When I get a cheap controller, one of the first things I do is strip it down and replace the caps with with low ESR Panasonic or Nichicon capacitors.

Re: yiyun controller going full voltage to motor with no input

Posted: Fri Nov 10, 2017 11:13 pm
by Quinc
Other then a bulge is there a way to test them? Also any tips on getting more amps out of them? :D

Re: yiyun controller going full voltage to motor with no input

Posted: Sat Nov 11, 2017 7:58 am
by zogthegreat
Hi Quinc,

Use a multimeter, set the meter to read in the high ohms range, somewhere above 10k and 1m ohms. Touch the meter leads to the corresponding leads on the capacitor, red to positive and black to negative. The meter should start at zero and then moving slowly toward infinity.

Usually it easier to just buy a higher amp controller. The YK43B is my favorite and it looks like they are available again on eBay:

https://www.ebay.com/itm/Electric-E-Sco ... 0005.m1851

(Here's the item description showing that it handles 24 - 60 volt)

http://vi.vipr.ebaydesc.com/ws/eBayISAP ... cureDesc=0

A big heads up though, the YK43B will dump a HUGE amount of amps to your motor! You will pop a wheelie if your not careful!

However, if your like me and you like to do things just "because", you can replace the fets to increase power, but it's a lot of work and you need a good soldering iron. The shunt can be modded to increase power. summerbear48 did a nice write up here:

viewtopic.php?f=18&t=3398

Re: yiyun controller going full voltage to motor with no input

Posted: Sat Nov 11, 2017 1:40 pm
by Quinc
Oh yeah! I run that controller on my mini bike and had it on my gokart for a while. Looking for something around the 40-60 range though so it wont blow the little 650w unite motor.


Re: yiyun controller going full voltage to motor with no input

Posted: Sat Nov 11, 2017 4:49 pm
by zogthegreat
NICE!!!!!!!!!!! :D :D :D :D

What's the motor on that?

(EDIT) I just found your build page. Once again, NICE!!

Re: yiyun controller going full voltage to motor with no input

Posted: Sun Nov 19, 2017 2:46 pm
by Quinc
Well son of a bitc.... It happened again. Rode the gokart for the last two days probably over 1 an hour on it. Today I plugged it in to charge and as soon as I plugged it in, it went full throttle again.. Doesn't matter if everything else is unplugged she still goes.. Wondering if it could be my power switch or possibly something else? 24v throttle with 36v controller? Luckily i got the last two off amazon and am able to return them. :)

Re: yiyun controller going full voltage to motor with no input

Posted: Sun Nov 19, 2017 2:53 pm
by zogthegreat
Quinc wrote: 24v throttle with 36v controller?
That could be your problem. If the hall sensor is expecting 24v and it's getting 32v, it might be activating because of that. robnewyork would be the guy to ask, but I haven't noticed him around for the last few months. (I hope that he didn't get hurt with one of his projects).

I would try swapping with a 36v controller if you have one, otherwise do the Amazon return.

Re: yiyun controller going full voltage to motor with no input

Posted: Sun Nov 19, 2017 3:22 pm
by Quinc
You might be onto something. Although I did use this same thumb throttle when I was running the YK big boy controller and floor polishing motor with 48volts. :)

Re: yiyun controller going full voltage to motor with no input

Posted: Mon Nov 20, 2017 2:55 pm
by Quinc
I talked to Rob, he is alive and well. His account got locked out and he created a new one but since no moderators are around they cant approve his posts..

Re: yiyun controller going full voltage to motor with no input

Posted: Mon Nov 20, 2017 8:43 pm
by zogthegreat
Quinc wrote:I talked to Rob, he is alive and well. His account got locked out and he created a new one but since no moderators are around they cant approve his posts..
Did rob have any suggestions? BTW, where are the moderators?

Thanks for letting me know that rob is OK, (chuckle), robnewyork, if your reading this, you understand our concerns about your safety! ;) :lol:

Re: yiyun controller going full voltage to motor with no input

Posted: Sun Jan 07, 2018 10:55 am
by Quinc
I think i figured it out. I got a new controller and didn't use the lcd display to show volts or use the charger through the controller. Hooked the wires up directly to the batteries. Been a couple weeks now and so far so good.