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Sur-Ron Light-Bee electrical troubleshooting

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    I can't charge my battery:

    Battery appears to be dead and you cannot charge it?

    Awaking the Battery after Auto-Sleep mode:
    1. Plug the charger into the Main power. Do not turn on the charger, then insert the charger into the battery charge port.
    2. Turn on the main power, the moment, the red and green indicators of the charger will alternately blink, turn off the charger and then on again.
    3. The red indicator of the charger will blink fast (0.5 second per time). The blink time will last to 20 seconds.
    4. After the 20 second blink, the red indicator will be a constant light for 10 seconds. During this 10 seconds, turn off at the power point and then on for one time.
    5. After Step 4, the “Forced Charging” function of the charger will be turned on. Then, the charger will work normally
    6. You may need to do this procedure up to 15 times.

    This video shows you exactly how to do it:

    1. In Step 3, during the red indicator’s 20 seconds fast blink, please do not turn off the charger. Otherwise, you need to start the procedure again from step 1.
    2. In Step 4, the action to turn off and then turn on the charger needs to be finished during the 10 seconds, when the red indicator is constant light. Otherwise, you need to start the procedure again from Step 1.


      I turn the ignition ON and nothing happens, no lights, horn or dashboard.

      Trouble turning on:

      1.Make sure you turn the key and that it is charged. There is a breaker in front of the battery, breaker needs turned on before operating.

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      2. There is a fuse in a small white box, check that the fuse is intact. If not swap it out. There is an extra fuse in the box. Its a 5amp 250 watt fuse if you need another. Without that fuse the controller is not turned ON and the lights and dashboard are not getting any power.

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      3. Battery load testing:

      Best is to use a incandescent bulb or a halogen bulb as they work great with any voltage

      Unplug the battery from the bike, let it rest for at least 30 secs, measure the voltage from the battery pack. Then connect the light bulb to the discharge port (there is no polarity on a incandescent light bulb). If you see the voltage drop (like these 2 pictures below) then it's likely the battery BMS that has an issue. In this situation please contact
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        My Sur-Ron not working or cutting out while riding but the lights and dashboard remains ON

        If the lights/display/horn works and they do not turn off or flicker then continue reading this section

        Can be either:
        1) Brake cutout sensors
        2) Kick stand sensor
        3) Throttle stuck
        4) A connector is not fully "clicked in"

        5) Tilt sensor (crash sensor)
        6) A problematic light

        1) Check the ebrakes. The brake levers are designed to cut power if pulled. In some circumstances such as a crash this connector could come unplugged and the connector may cause intermittent cutout until plugged back into the lever. If you see a cutout, check the ebrake connector! If it is loose of comes out if you pull on it, add a couple drops of superglue to hold it in place.

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        Disabling ebrakes for full throttle during braking

        The goal of ebrakes is to cut power from the motor as a safety measure, however there are instances where this may want to be disabled such as during an actual race, track use, burnouts, or any situation where you need to already be hitting the throttle before you let go of the brake and require extreme agility. Please see the post below for in-depth instructions on how to service the ebrake connection

        2) Kick stand sensor, make sure that the kickstand is up and that the wire is not ripped out of the kickstand (near the pivot). In case of a doubt you can unplug the sensor but you will have to remove the bash guard and access the triangular 3 pin connector and unplug it.

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        3) Throttle stuck

        Maybe the cable it too tight and the throttle is not returning to 0, you can adjust the throttle cable on the hand throttle adjuster, just slide the rubber boot, loosen the lock ring and turn the adjustment screw in.

        Video explaining how the throttle works. Note: you dont have to remove the Bach guard you can just take a look through the holes in the bash guard to make sure that the cable sheath is in the bracket.

        4) A connector is not fully "clicked in"

        There are many connectors on that bike and some are critical, if a wire is pulled out a little or a connector is not fully pressed in then the motor can cut out while riding.

        Now you will have to remove the bash guard to access these connector. Make sure that you do not pull on any connectors or wires!

        Please take a look at this video

        5) Tilt sensor (crash sensor)

        The crash sensor is located under the top part of the controller, if you have disabled the brake & kickstand sensors, adjusted the throttle and checked the connector and you still get cutouts (without ever loosing power to the dashboard and lights) then best would be to unplug this sensor and test the bike. So far we havent replaced a single crash sensor so it's very unlikely that it goes bad. If you take a huge jump and land hard, you can trip that sensor (happened to me) so keep that in mind that this sensor is not for extreme jumps!

        To access this sensor you will have to pull the controller out, it's a little black box between the battery and then top part of the controller.

        Please watch this video on how to change the controller, at the 3:00 min mark Matt is pointing at the crash sensor:

        6) Rear or front light is pulling the brake cut-out signal.

        Disconnect both wires off the rear light and disconnect the front head light (front head light connector is located under the ignition housing).


          My Sur-Ron is slow

          Sur-Ron Street legal mode is likely engaged

          Please click this link to see the video on how to change from full power to street legal and vice-versa.

          On the Light-Bee this is a (very) low power mode (like 8-10mph) on the Light-Bee X (LBX) it's a street legal mode (if that applies to your state/country) and it's locked to 25-30mph.

          Now here is the trick, If your bikes was bought before May 2019 then:

          Cutting this wire will limit both power AND speed depending on the model you have . In theory you could put a switch here when you go offroad but the idea is you simply cut the looped green/black wire.

          If your Bike came with the factory street/slow mode, just look for the green/black wire under the black sheath and crimp or solder both ends together (or twist them together if you can't wait!)

          If your bike was bought after May 2019 then: It's the opposite, cutting the green/black wire will make you bike fast again!

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            Display and lights work but the motor does not move

            Before continuing with this section make sure you check all the sensors and connections covered here: CLICK ME

            If you have this cable (see below) then open the battery cover, turn the breaker OFF and unplug the battery connecter and connect this harness to the bike and then connect the other end to the battery. The LED will flash is there is a trouble code stored, wire down the code and check the following error code chart

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            First test should be the wheel spin test, see if the rear wheel spins without much effort. If you can't rotate it with a finger or 2 then it's possible that the controller is shorted out

            Take a look at this video:

            If the motor/rear wheel spins fine and all the sensors are unplugged and you checked every connection then it can still be the controller or a bad connection in the harness. Best would be to take a video of the issue and email


              Motor works (might be slow too) but the lights/horn/display wont work

              This failure state is uncommon but is something you could look for if having problems.
              The red and black power wires going to the controller has a small red wire soldered to the ring terminal as seen below (The black has the same little wire so check the black too). This goes to the 12VDC voltage converter. If this becomes desoldered or breaks off it will prevent the lights, US, horn and dashboard light up but also could make the motor run slow,

              You will need to pull out the controller you can use this video to help you out removing the controller. Just make sure you removed the battery before proceeding with this

              Once you have the controller pulled out this is what you need to look for:

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                My Sur-Ron dies completely and/or the lights/dash flash

                Before continuing with this section make sure you check all the sensors and connections covered here: CLICK ME

                If your Sur-Ron display/lights flash 1-6 times and shuts down and 30 sec later it starts to flash again in a loop then it's possibly the battery BMS that is acting up. Best thing you can do is to leave the ignition and breaker ON and then connect the charger to the battery, if the lights stay ON then it's very likely that BMS is acting up. So go down this post to step #4 and do the controller bypass. If the lights and display works then email Luna Cycle at (best would be to make a video of the issue as the support agents will ask for it)

                If you Sur-Ron does not do the 5 flash thing then please continue with the troubleshoot:

                First question, do you have the testing cable (click this link) if yes please turn off the breaker and install it between the bike and battery, flip the breaker and tell me how many times the red LED blinks. IF you dont then please continue. If you do have it and does not blink then please continue.

                The first step would be isolate the issue.. it can be the battery or the controller or just a loose connection.

                1) measure the voltage with a multimeter: flip the ignition OFF ,then the breaker OFF, unplug the battery fully, wait 30sec, and measure from the charge port, you should be reading anything between 45V up to 67.2V depending on the state of charge.

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                Next would be to plug the battery back, measure the voltage from the charge port (see attached) and while measuring flip the breaker ON (note the voltage) then turn the ignition "ON" and measure the voltage again. As you can see in my case the voltage went up a little .. that is because the BMS was sleeping and we just woke him up (really). If you turn off the breaker and wait 30 sec or so the voltage should go back down a little.

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                2) Next step would be to pull the controller out a little and inspect the the little wires soldered to the main power lug on the controller.

                Just click here to know how to do it and what to look for

                If one is not soldered properly then you will need to solder it back!

                Dont reassemble the bike yet until you test the bike! The next few steps will require you to have the bash guard and controller out.

                3) If you havent inspected the connection yet then it's time to do it, dont pull on the wires, just press them in firmly, check if there aren't any wires pulled out of a connector.

                Please watch this video:

                4) Unplug the DC-DC buck converter from the system and try the bike, you wont get any accessories working but it can help to see if there was an sensor pulling a voltage down, see previous at the 30sec mark to know what to unplug.

                5) ONLY DO THIS STEP IF YOU LIGHTS WERE FLASHING AND DIYING : Now it's time to disconnect the controller power from the battery, so make sure the battery is fully unplugged (very important). Then using an Allen wrench remove the bolts securing the red power terminal, once it's off the controller take some electrical tape and wrap the copper lug so it can't short out on the frame or the negative post. Put the battery back in and flip the breaker ON and the ignition, does the lights and dashboard flicker now or are they staying on? IF they are ON that means the controller is likely damaged and needs to be replaced. If lights are still flickering then it's in the harness or in the battery.

                Just make sure that you tighten the main power lugs back properly, you can use a drop of blue locktite on the thread so it wont loosen up overtime. And while your at it , use dielectric grease over the lugs to prevent oxidation/corrosion! On your next big maintenance inspect your connection again.

                6) If not then chances are that the issue lies in the battery BMS or the wiring harness in the battery. Dont loose hope yet there is a known fix that you will likelly be able to perform and will be a permanent fix! So far 9/10 times it's this little wire!:

                The procedure is on a PDF that you can download here, if you have any questions or unsure about your results please email LunaCycle at , ask for Seb and make sure to write down what tests you did, your measurement and attach photos and videos!
                Attached Files


                  Everything else has been tried, still no joy:

                  Unplug the lights. Both rear lights and any aftermarket modded lights (fisher light headlight etc) . Under a very few limited circumstances we have seen this cause the bike to show as dead.