Solve the battery or ignition problems of your xiaomi scooter

This tutorial aims to help people who have scooter power on issue. It seems that some owners of scooters dating from 2016 have problems due to poor management of Regenerative Braking system . We advise all those who have one to put “WEAK” the level of ” Range of charge mode” in your ninebot app or mi home app

This article is a synthesis of infos found dealabs  (thanks b18685) and forocoches  for pictures

1er case, the easiest

Disassemble the protection that protects the battery pack

Without disassembling anything else, just unplug the large red and black wires from the green round control console (no need to remove the battery!)

  • Connect the power supply to the scooter as if to recharge and wait 30 seconds
  • Disconnect power cable
  • Reconnect the large red and black wire connector
  • Press the start button on the scooter

If this works, close the battery cover and set the” Range of charge mode” setting to “weak” on the ninebot or Mi home app until firmware version 1.31 is available. You can adjust your rear brake manually so that it is a bit more efficient without rubbing on the disc.

2nd case more annoying but feasible: connector desoldered

A connector has been desoldered or made a bad contact (red circle, we do not see all of them in this picture)

Check their connection and redo the solder especially by unplugging ALL the wires that connect battery to the control console and of course by locating them beforehand with a small drawing (no need to disassemble the battery)

Also check that cables are not damaged

  • After welding, reconnect the wires
  • Connect power cable for 30s
  • unplug power cable
  • Power on the scooter
  • If she turn on close the battery cover

3rd case / A fuse has blown

motor brake when the battery is 100% sent too much juice during a throttle lag) (if you are in “middle” or “strong” mode and firmware version <1.31) the system has blown the “Z” fuse ”

Detailed tutorial coming soon

 

 

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149 thoughts on “Solve the battery or ignition problems of your xiaomi scooter

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  1. I’m at dead end 😦
    Xiaomi support is terrible. I still receive this error (BMW password is wrong(22)).
    Though through the app I receive cell voltage to every cell, everything, temperature sensors.
    But can’t run on full power only to 12.5 and I receive 2 long and 2 short beeps constantly.

    I’m considering re soldering microprocessor maybe? Any advice will be very wellcome

    https://photos.app.goo.gl/OTQO3z88j2qXYKms1

    Like

  2. Assuming you still have your original controller board, it should know the BMS password. If not, it must have got corrupted. The only thing I can suggest is to contact Ferry in Moscow who have cracked the BMS code and know how to initialize the controller.

    I’m not quite sure of their contact details but it like Whatsapp to +7-904-219-51-32 should work. Otherwise, look on Youtube for the videos uploaded by Mini and see if there are contact details in those.

    They are a commercial organisation so will want to charge for repairs

    Like

  3. Hey mates! I have kind of a weird problem with my xiaomi scooter. Maybe you can have a look at my video and tell what I could do to solve the issue. The scooter does not getting turned off. And it’s in kind of a loop and not useable.

    Like

    1. Paul, the green light on the controller board indicates a loss of communication – in this case almost certainly to the handlebar control panel. Either you have a broken connection between the main controller and the handlebars, or the handlebar circuitry is faulty.

      But first, have you tried a complete reboot? To do this, disconnect the plug with the thick black and red wires from the controller. This removes the battery power. Then re-connect and see if you still get the problem.

      If you do, check the 4-pin connector on the controller and then you may have to undo the handlebars to get at the connector at that end of the wire. See the photo at https://www.passiongadgets.com/mijia-scooter-handlebar-circuit-board/ where it becomes obvious what you should look for.

      If all that checks out, then I have no more suggestions.

      Like

  4. My scooter randomly stops and make 3 short beeps and one long. This may happen twice in a day or with 10 days of time difference. Battery voltage is always OK. Cables and connections are ok. What I usually do is to reset the battery and some how the problem is solved until next time. Maybe I reset 5 times or 50 to solve the issue. What I suppose that could be happening is that a sensor is not working properly. Anybody knows which sensors are and how to check if they work OK? Thanks!

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  5. Hi Peter.
    I have a mijia scooter.
    but it’s not working because fail of BMS.
    I am trying hard to find the cause.
    Do you know this part in the BMS board?
    It making is L04A DW location no is U4 and U5.
    They are heating at connect battery.
    they remove at the pcb BMS red led on off repeat.
    I think they are fault then I want know spec of U4 and U5.
    Thanks~

    Like

    1. Shalom, I don’t have a BMS board on the bench at the moment. As I recall, U4 and U5 are the two little square integrated circuits with 8 pins each. Is that right? Next time I take a battery to pieces I will see what the part numbers are.

      Like

  6. Hello everyone

    I have the exact same issue as amarinpietro (october 6th 2017).
    The leds dont flash at all, and one of the connector on the side of the battery is broken.

    As I’m new to soldering, is it normal that when I put the broken electrode back in contact with the battery and the central electrode, that it creates sparks ? Can I safely proceed to soldering ?
    I’ve also put some flux on the contact.

    Thanks for your help.

    Like

    1. It could be OK, or it might not be!! It’s difficult to tell without a good photo of the broken parts. Each of the 10 cell packs is made up of three batteries in parallel and if the connection between these three breaks, then they may be at different states of charge (voltages). In this case, when you make the connection again, the higher voltage cell with try to charge up the lower voltage cell causing a spark as the electricity starts to flow. But if the break is between two of the 10 cell packs, then a spark is wrong.

      Can you post a clear photo of the broken bit please?

      Like

      1. Where that break is definitely must be connected to the battery underneath. The sparks must as electricity is flowing from the higher charged cell(s) to the lower charged cell(s). It’s quite difficult to solder directly to the nickel base of the cell because you have to be quick so as not to overheat the battery and yet there must be enough heat to get the solder to flow and not just form a blob on the surface.

        Scrape the surface well to expose fresh metal, apply a smear of good flux and then heat quickly with a reasonably powerful soldering iron and some fresh solder. Hold the broken tab down with a screwdriver held in your third hand (!) as you do this.

        Good luck

        Like

      2. Hi Peter,
        So I’ve managed to solder there and I think it worked because that individual battery quickly heated, which I think is due to the charging process (which scared me quite a lot at first), but it’s back to a normal temperature now.
        However the LED are still not blinking, is there a way to turn it back on ? I’ve just bought a multimeter, could you please tell me which electrodes to test ?

        Thanks a lot for your help.

        Like

      3. I’m a little worried that the battery heated but it could be OK if, for instance, it was discharged and needed to be charged by the other two cells in the pack.

        You can try rebooting the BMS. Right by the blue LED that is not lit (!), there is a tiny button. Press and release this and the blue light should start flashing at one second intervals. If you see the red LED flash four times and then stop, there is still something wrong.

        You can use your multimeter to check the cell pack voltages. There are 11 terminals on top labelled B0 through B10. If you connect the black lead of the multimeter to B0 and the red one to B1, you will see a voltage of, say, 3.6 volts. That is the voltage of cell pack 1. Note that down. Next, put the black multimeter lead on B1 and the red one on B2 and write down the reading as cell pack 2. Repeat until you have all 10 cell pack voltages. The last one will have the black lead on B9 and the red lead on B10.

        Ideally, these voltages will all be equal to within about 0.02 volts but in your case, I would expect cell pack 3 to have a different voltage because of the repaired break. Once the BMS is working again, you can charge the whole battery and the voltages will even out (you may need to charge and discharge a few times if there has been a big difference). When the scooter is working, you can see all 10 cell voltages reported on the MiHome app if you run it on an Android device. These are an important diagnostic because in a working battery they should all be equal.

        Like

      4. Hi Peter. I tried pressing the button but nothing happened.
        My measurements are:
        B0-B1 : 0.06
        B1-B2 : 1.26
        B2-B3 : 0
        B3-B4 : 3.62
        B4-B5 : 3.62
        B5-B6 : 3.62
        B6-B7 : 3.62
        B7-B8 : 3.62
        B8-B9 : 3.62
        B9-B10 : 3.62

        What do you think? I guess B3 is simply empty, because I can measure the voltage from the B0 to B10 (which shows 26.6V) as well as measure from the black electrode to the red electrode.

        Like

      5. However, when I put the two multimeter leads in the two plugs that connect to the motherboard, it only shows 2.37V.
        When I measure the voltage between the black plug and B10, I get the full voltage (26.6V) but when I measure from the red plug to B0, I only get 2.37V.
        Do you think there’s another problem with the black wire ?

        Like

      6. This does not look good, Arthur.. But first, do not worry that the voltage to the motherboard is only 2.37v – the BMS has turned off the supply because it can see that the battery pack is faulty. The actual power comes from the thick black and red wire and this should be 36v not 26.6v. This is the problem.

        There is something seriously wrong with the first three cell packs. For a lithium cell to read zero it is not simply empty, it either has a short circuit or it is ruined or is not connected so there must be another – or more than one break in the area between B0 and B3 so you should unsolder the thick black wire so that you can get the black plastic off all the way along – and on both sides. Look for more broken connections and re-make them.

        Do bear in mind that at the positive end of each battery, the terminal is very close to the outside metal container and it is vitally important that you do not make an accidental connection between the two. If you have done this on B3, it will not be good for the battery.

        I feel fairly certain that B0 has got disconnected but you will have to look closely at all the connections, both to the bent over metal tabs and where the metal strips are spot welded to the individual cells.

        In hindsight, I should perhaps have suggested that you find someone nearby who is experienced with soldering. In this environment of high power batteries, a dropped blob of solder in the wrong place can cause such a short circuit that I described above.

        Please look very carefully at all the connections to do with the first three cell packs, i.e. 9 cells.

        Good luck!

        Like

  7. Hi,

    I just received my Mijia M365 and right off the box it gives me an error code 18 (hall sensor error), so the motor doesnt run.

    Any idea what I should do next?

    Like

    1. I’ve not seen this problem but what I would do before sending the M365 back to the store is to take the cover off the bottom as shown in the first case at the top of this thread and check that the connectors to the controller board are properly plugged in. The Hall effect sensor is connected by one of the little white plugs on the left of the photo.

      If it’s not this, then let’s hope the problem is not that the sensor has failed because I would think replacing it is something that should be done under warranty.

      Like

    1. I’m sure it would be possible to use a different chemistry LiPo battery – IF you can crack the BMS firmware to allow for the different charge/discharge characteristics. For instance, batteries based on Lithium Iron Phosphate have a fully charged voltage around 3.7v while the lithium metal oxide batteries are fully charged at 4.2v. And other chemistries need different charging rates.

      For more information, see: https://batterybro.com/blogs/18650-wholesale-battery-reviews/18880255-battery-chemistry-finally-explained

      Like

  8. Any help would be great, scooter will not power up. Have tested all of the connections, the voltage coming out of the thick red and black wires was 3.6 I believe. I checked the fuse and get multimeter is changing from 1 to 0. I did notice that the board has 2 Z fuses on it and checked both. The only thing that happens is a red flashing light that flashes about 4 times when I plug the power in and then stops.

    Like

    1. Yes, the welded connection B0 on the battery has lifted as shown in option 2 at the top of this thread. This is the one nearest the back wheel. Do not be misled by the fact that you have 36v coming from the thick black and red wires. Connection B0 is for the battery monitoring and without this the BMS doesn’t know where to start so it shuts down. Repair this and press the little reset button next to the LED and you should get the blue light on again.

      Like

      1. I went back and checked the connections and you were correct. I resoldered B0 and voila!! The blue light came back on and I was able to turn on the scooter. The battery was low from the last time I used the scooter but I checked the Ninebot app and noticed I was only getting about 19km/h. Could this be because of low battery? I’ll wait for a full charge and check again. Thanks for pointing me in the right direction.

        Like

  9. Hello there! I am hoping you can help me. I had a problem with my M365 where the B0 contact came loose and I think it touched the scooter frame because there was burnt and melted plastic wrap. I managed to get Banggood to supply a replacement battery but when I installed it the scooter is still dead. The power button does not work, and there are no LEDs on the main controller board. The blue light is on the BMS board but it doesn’t seem like power is going to the main board. I tried the step 2 above in this post (unplug battery, charge for 30secs) but this did not work. Any suggestions? I thought maybe something to do with the BMS being paired to the main board? Is this the case? or do you think the main board has been fried? Thanks!

    Like

    1. Just a few points: is the blue light on the BMS board steady or flashing once a second? Can you confirm that the little 3 pin plug with green, yellow and white wires is properly connected (and the main plug with thick black and red wires of course). Do you have a voltmeter to check that there is 36-40 volts across these two wires?

      The BMS doesn’t need pairing with the main board; battery packs are interchangeable without fuss.

      Where in the world are you? Just in case you’re local enough for some assistance.

      Like

      1. Thanks Peter, I am now trying to remember what the blue light was doing. The scooter is at home at the moment. I am fairly certain it was flashing once per second. I was quite sure the green, yellow and white cable was secure too and the battery was at 36.5 volts. Good to know the BMS doesn’t need pairing but I am suspecting the main controller might be fried and possibly the LED controller too. Do you know if there is a way to test these components?

        I am in Australia. Is that close? 🙂

        Like

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