M.L. Toys
M.L. Toys
HobbyMasters M.L. Toys
Electronic Scooter Controllers have become a popular addition to our vehicles. Ask specific questions about ESCs here!

***WARNING*** this section is for ADVANCED MODDERS. if you try anything in this section you NEED to expect minor issues with the build up to and including complete FAILURE of EVERYTHING in your freshly built BPRO.

Have fun ;-) :-)
User avatar
By The Eagle
hi all...I joined over a year ago...but haven't posted in ages...and even then, haven't posted anything of value...but I have been modding away, probably learning a thing or two, and might be getting close to contributing, lol

before i get to the point, I wanna say thanks to everybody past and present...I read this site all the time and have learned a ton! plus, some of your projects are just crazy (ahem, 66duece for example...)

anyway, my point: I picked up a couple YK31C controllers from amazon and am trying to figure out if I just got back-to-back DOA's or I'm doing something wrong
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There's been several Chinese vendors that have come and gone, all selling them for $12-15. I had done some research on MPW and it looked like they should have been OK. Originally I bought one of them sometime last year...but had some trouble. At that price, I figured order another because I prolly screwed it up. Then ordered a third for backup, lol.

I've had nothing but trouble. I always start electrical projects with what I call I had the YK31C on a bench and I'm hooking up the bare essentials, connecting power last, etc. I used a razor thumb throttle the first try (prior to that I put 5 V on it and metered the signal wire to see that it worked. The voltage adjustment was kinda jumpy...but it covered the right voltage range). I was hooked directly to the rear right motor on this Dumar Yamaha Raptor I'm working on, with a block under the rear so the tire could spin. When I shorted the "key switch" wires, nothing spectacular happened. I slowly give it some throttle, and nothing. I poke around checking connections, try a few more times, then it start to work. The connections were all fine as far as I could tell. It works for 3-4 throttle cycles, then I goose it a little harder and it stops working. I assumed I blew something I poke around...fuses, etc seem good. Try some more, and I get some more intermittent functionality. Then work got really crazy and everything sat for a while. In the mean time I order the extras assuming I messed it up.

The second try, this time with a different twist throttle, i start out about the same, but on about the third slow twist on the throttle it goes to full speed and locks there. The spade connector I was using to hook the +24 from the battery into the power input of the controller actually fused to the connector (like when you have a bad connection that arcs...but this connection definitely wasn't bad). These are aftermarket motors, but they aren't anywhere near out of spec for this controller or 24 V, especially propped up off the ground with no load. In fact, hooking the 24 V batteries directly to the motors works just fine (steady current was just under 5 amps, i think). The battery fuses are 30 A, which I guess is a little high for a 500 Watt controller on 24 V (a 20 A fuse mighta been a good idea...500 W/24 V = 20.8 A)

Anyway, I complained to the vendor...they asked for pictures which i sent (and supposedly and uploading here). They said they couldn't explain it and will give me replacements, if I pay to ship these back....which isn't worth the cost.

so I've moved on to a different controller with a cool linkage that I'll post soon. But I wanted to toss this story out there and see if I'm the only one...or even better, I'm doing something wrong and maybe can put the 3rd unit to use :)

about those pics...go figure...500 kb limit. I'm late for work, so then here's the dropbox links: ... 6.jpg?dl=0" onclick=";return false; ... 7.jpg?dl=0" onclick=";return false; ... 8.jpg?dl=0" onclick=";return false;
By 66deuce
First, thanks for the nod!

Now, as for speed controllers.........I know just about everyone here uses the hall-effect type scooter ESCs, and they seem to have good luck with them by and large. Personally, I tried exactly one, and it was faulty out of the box. So I've stuck with ESCs that use a potentiometer, which I find easier when it comes to fabbing a pedal arrangement, since potentiometers can be had in just about any size with any value. I have had very good luck with this ESC in particular: ... EBIDX%3AIT

There are US sellers offering it for a couple bucks more as well, and there is a version with a housing. Then you just have to figure out what shape & size 100K potentiometer you with to use (for a twist throttle, could just use the included one). Though I've doubled them up now, the single unit did not fail, even under very heavy load in my red Wrangler. I tried a full throttle punch with me (185 lbs) in the 160 BPRO, and had my Fluke amp clamp on it; pegged 128 amps at one point (3,072 watts), was over 70A much of the time, and the ESC is still fine, even though they're only 60A rated. Another one of these has been getting abused in their Jeep Hurricane at 18V with no trouble whatsoever.
Thanks for sharing. I had been eyeing these controllers for a couple years now but it's nice when someone else takes the plunge first... :lol:
bendoerfel wrote:you guys have any pictures of the speed controller with potentiometers wired up with a throttle?

If you look at Deuce's build, you'll find pics of his potentiometer linkage, if that's what you're asking. There have been lots of other people who have posted similar linkages. The pics in my original post were a twist-style hall effect throttle.
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I'll probably start a new thread on the replacement I ended up using for this Dumar fourwheeler, it's a potentiometer-based setup, but with a different kind of linkage.

If you were asking about how to wire it, there are three wires that make it work (if there's 4 or 5 wires, the extras are for additional stuff, like a power indicator): a 5 V and ground connection that "powers" the hall effect sensor or potentiometer and a signal output that's either the sensor electrode of the hall effect setup or the "wiper" of the potentiometer. Not all controllers can drive both types. You have to watch for the max current spec of the 5 V power output and then the return signal from the sensor wire needs to fall in the right range. A potentiometer output covers nearly the entire 0 to 5 V range while the hall effect ones typically only hit 4-point-something and tend to have a non-linear response. When I was reading up on those YK31Cs I found that a lot of scooter controllers can't handle throttle signals above the mid 4-Volt was unclear if they had any kind of over-volt protection (although that circuitry isn't difficult or expensive and you'd certainly expect a good controller to have it).

wesleyb82 wrote:I have sold many YK31C controllers and overall have had very few problems with them.

If you are looking for a 0-5k pot throttle check these out: ... 1036822018" onclick=";return false; ... 1c309241d9" onclick=";return false;

Thanks Wesley, good to hear, maybe I just started out 2 for 2 with YK31Cs. What vendors have you purchased them from? Mine were overseas 3rd party Amazon deals...but they had positive reviews on other products.

Thanks for the links, too, those pedals look sweet!
I don't normally sell individual controllers since there is a member here that already does that but I do have them on hand and always stand behind the parts that I sell 100%
Had troubles with my YK31C also this week. The wire harness/plug to the motor melted for unknown reason and the motor was getting constant full voltage. My daughter was in the car and we could not stop it. I had to grab her and the car went crashing into a tree. The esc was sending full voltage to the motor even when she turned the key off and the throttle did nothing. This was with a 500w motor at 24volts.
wesleyb82 wrote:I have sold many YK31C controllers and overall have had very few problems with them.

If you are looking for a 0-5k pot throttle check these out: ... 1036822018 ... 1c309241d9

Would these be good for a razor 24v dirt quad (350w)? I have a JUST turned 3 year old little girl and she was riding fine till she had the handlebars fully turned and twisted the throttle all the way. So I'm looking to put on my first ever POT. Problem is I don't know much about them or which one I should get for the mentioned quad. Also I have a upgraded set of 36v batteries and controller I'm looking to put on down the road. Adding this POT to lower total output won't cause and added power when I up the V's and controller will it?

Thanks in advance for any and all help!
Please help me! I have a. Yk31c speed controller 48v 1000w I purchased this with a twist throttle control, I have it connected to the derailur and on the motor side I have a 48v 1000w brushed D.C. Motor from monster scooter parts.... I am just completely lost on the wiring I can't get throttle control. I have 4 wires a yellow a blue a black and a red (that has a thick steel wire different from the other contacts) I have been doing all my testing with a 12v 9ah battery and can make the motor move a thousand ways but CANNOT again throttle control please help! Text me if you want! And I'll send you pictures. So frustrated 631 662 9231
User avatar
By powers
Good day

Thick black and red is batery power
Thick yelow and blue is motor (need test for angle rotation)

you need conect lock for aktivated controller unit
and throtle .. be carefull wires .. black is - red is + a green is signal .. maybe you must change wires in connector for good wirring ! here i make manual for my blog :

I'll help you if you do not know what to do


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