Yiyun LB27 24V 250W controller for scooters with brush motor review and manual.

In this review you will learn all the details about the scooter control unit from the Chinese company Yiyun my rating and manual how to connect it with other components.

Here is pros:

  • It has small dimensions
  • Supports classic throttle
  • And has a good price
  • Battery protection is particularly useful for lead-acid batteries that do not have a BMS circuit

Here is cons:

  • The control unit is not waterproof
  • 22A which can give it will heat but is max normal current draw on road is about 5A.

Review Summary

LB27 is good controller for for easier load or example, an electric scooter,a quad bike for children different drives where is used the brush motor. Wiring Yiyun LB27 24V is similar to Yiyun YK31C 36V from the same manufacturer. But this controller is smaller and has fewer terminals.

The place where you place the control unit must be without water reach yiyun LB27 is not waterproof – no waterproofing at the control unit outlet.

Detailed description of Yiyun LB27 controller

Controller has alumium case for better cooling , the case LB27 has one side extended so that you can drill it and place it somewhere on the frame of a quad or scooter.

  • It 250W is ony specific rate controller has maximum current about 21A can give real 500W.
  • The controller is stored in the aluminum cover,and secured by cross screws.
  • Cable wires with connectors are about 15cm long.
  • On the top of the cover there is a description of the wiring but it is Chinese so I will show below how to correctly connect the control unit.
  • Supports the Hall sensor three-wire control throttle.
  • LB is only for brushed motor.
  • The controller has an integrated battery protection, for example, when the 24V.

Yiyun LB27 controller wiring manual

Many connectors? read the instructions below

You must connect the power wires correctly, you cannot change them + – it is not clear if the control unit has reverse + and – protection.

Here manual with fotos how to connect motor, throtle,brakes now i describe connector outputs:

Installation Information:

  • Power ( rough red connect the positive pole ,rough black connect the negative )
  • Motor( rough blue connect the positive pole ,rough yellow connect the negative )
  • Indicator light (thin black connect the negative , thin red connect the power output )
  • Brake light 
  • Brake (thin black connect the negative , think yellow connect brake signal )
  • charging port
  • Electric lock 
  • Speed handle ( thin red connect +5V , thin black connect negative , green connect signal )
Alternate version of schematic diagaram LB27 24V controll unit


Motor wire If you turn the wires into the motor, the motor changes the direction of rotation, a suitable switch adds reverse

Throttle The most commonly arranged drivers on the throttle is +, signal, minus, but on this LB27 control unit is +, -, signal, the wires need to be replaced correctly. Here’s a tip for a throttle hat works well with all controllers .

Lock just connect the blue and red wires to activate the control unit.

Power indicator be careful that the voltage indication goes directly from the battery You must not short-circuit the voltage, it must not be connected to 5V outputs, otherwise the control unit may burn.

If you expect higher performance (the controller can supply up to 20A), place it in a location where it will be cooled.

Technical Parameters:

  • Watt:250w
  • Voltage: 24v
  • controller: Brushed controller
  • Match Motor: 350W Brushed Motor
  • Dimension: aprox 2.75 “x 2” x 1.5 “
  • Weight: 8 oz
  • Brand: Yiyun
  • Model: LB27

If you have questions, write a comment:

31 thoughts on “Yiyun LB27 24V 250W controller for scooters with brush motor review and manual.”

  1. I built one bike with 7s lithium ion 24 volt. Full charge is around 29 volt. Works fine. Second bike is lead acid 4x6volt series 24 volt. Full charge about 25.5 volts. Also works fine. I would like to add one more 6 volt battery to make it 30 volts. Full charge would be around 32 volts. Will that work with Yiyun LB27 controller? It handles 29 volts ok but what is the safe maximum?

      1. selam ben Mustafa,Türkiyeden yazıyorum,CT-302S9 kontrol ünitem bozuldu yerine aldığım ünitede gaz teli jakı 3 uçlu eskisi 6 uçlu idi nasıl yapacağım yardım lütfen teşekkürler..

  2. Hi!!

    Thanks a lot for all this information, very useful!!
    I connected everything but, seems like the throttle is nos working, and the motor is always running in a very low and constant speed, no way to use the throttle.

    Maybe is the wiring connection in the throttle as you say?

    Thanks a lot!!

      1. Attachment

        My problem is similar. It seems it is for the battery level indicator. So I connect it to my front LAMP that has a series of LED for that and has 2 pairs of wires, one for the sound beep, other one is free. See the attached photo.
        I have another problem: where to connect the BREAK and BREAK LIGHTS plugs? I have got a set with 2 break handles, both having a pair of wires. Attached. Logical would be to use one handle to the break LIGHTS of the Controller, the other one is for the Engine BREAK plug of the controller. Is the handle overrules the throttle if I use the break handle at the latter case? I do not think so. As I have mechanical traditional front wheel and back wheel breaks (no disc brakes) on my bike and I have no 24V break lights, better not to use the 2 plugs (break and break lights) of the controller at all?

        1. Attachment

          As this description was the most usefull for me, I update my break and break lights issue above according to my experiment since then:
          Both work correctly as expected!!!
          I have simulated the break handle with a push button as seen on my photo. The break button/handle stops the CURRENT to the motor even the throttle is on. So it overrides the throttle. But the motor (so the wheel) still rotating a bit, so you need a mechanical break to stop it (like the wheel V break). Keeping the throttle always on, the button ON stops the current, the button OFF restarts the current. The 24V break light is ON only when the throttle is on (so the break lamp lits correctly).

  3. Hi, Can you tell me what the black connector with black and red wires connects to. My retail seller is useless and says just to experiment – Not re ccomended. Thanks , Dave.

  4. This information is very useful. Would it be better to use a 20A or 30A fuse in this set-up?


      1. Hi, I built a go kart for my daughter using this controller. It worked perfectly but I think I have now blown the controller as I was driving it myself and I think I’m too heavy and there was too much current draw. I now have 24v going to the motor constantly. Throttle and on/off switch having no effect. I have ordered another controller but I want to put a fuse in line the 24v input to the controller. Would 20A in line with the positive supply from the battery to the red positive input be good enough or should I use a different size fuse? Thank you. Pete

  5. Hi Ivan. I bought and installed this controller on my grandchild kid motor bike. I also replaced one RS390 6V gearbox with a two RS390 12V gearboxes connected in series, installed a 29,2V 4Ah Li-ion battery and hall sensor based twist throttle. Do you know how this controller regulate motor speed, by regulating constant voltage from 0V to 29V or switching a 29V ON/OFF depending on demanded speed? What I am interested is, may I connect both electric motors in parallel, and limit max motor voltage by limiting a hall sensor signal voltage to, for example 3V by installing a resistor on a signal wire? Now, while motors a connected in series, if one gear in one gearbox broke, bike stops moving, because they act like a differential axle, motor of broken gearbox spins freely while a good one stays still. I wrote this on English to help other to read if interested.

  6. Do you know a switching frequency of this regulator? What I am interested is, may I connect a 12VDC motor, 25W to this controller and keep throttle under 50% of effective voltage (50% of PWM pulse) without risk to harm a motor. If the frequency is high enough, motor coils shouldn’t be saturated, and everything should be OK. Or, maybe you have a better idea?

  7. Hi, can this controller be made to work with a PAS sensor, so that I have to pedal before the motor will work?

  8. i have a lb27 controller hooked it up and using finger throtle i get no voltage to motor what is wrong

  9. I am looking for 24v x250wattb brushed motor controller with fewer terminals to interconnect battery, 24v x 250watt pmdc motor, padel assist sensor and ignition (on and off) switch. If any body can help

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