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

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  1. How can we identify the year of production? The ninebot/segway app states battery production date 2017-02-20, and a sticker on the box the scooter came with states 2016?
    As long as i turned on WEAK in the settings nothing should happen?

    Like

  2. I have the problem since yesterday after 5 days happy driving…. X_X
    I was braking and the scooter suddenly powered off. It can not be turned on again. I have also charged over 8 hours and no effort.
    I tried the 2 methods above and still cannot turn on. It seems to be a common issue because in youtube there are some videos show the same problem. But some videos (https://www.youtube.com/watch?v=5gRBJVtp5dk) show that the TRANSISTOR is kaputt while others show that the battery control is kaputt.

    I really dont know what to do… Can someone help me with more specific tutorial?

    Thanks a lot!

    Like

  3. I have a problem with my m365, since i braked with a fully charged battery, the scooter turned off and i could not start it again. I opend the battery cover and the battery light lights continuously blue. Can you help me?

    Like

      1. Was your battery 100% charged up when you were braking? What firmware you had during that moment?

        I have the same problem, but my battery was just around 30%, firmware 1.3.0, scooter production date 2016-11. Just pushed the brakes and it turned off.

        Do you think changing Z fuse will solve my problem?

        Like

  4. Is the tutorial announced in the article still coming? And way more important could anyone please tell where to get a matching replacement fuse?

    Like

  5. hI BOWO i am having the same problem, would you give me advice? If you are in Indonesia would you send your phone number to 082123266979?
    bergowo

    Like

    1. did u solve the problem…..I also have this problem….i also live in Jakarta……I buy from Jakartanotebook…..only play 1 week then broken….and they they want to repair….XXX

      Like

  6. My scooter just stopped when working hard going up a hill. I was convinced it was going to be the fuse and got replacements. But I was surprised to find: (a) two fuses and (b) neither was blown.

    The only sign of life is when I press the ‘reset’ button and a LED flashes four times. Otherwise completely dead so I think the battery management PCB is faulty. I can only find a whole battery pack as a replacement; no one seems to sell just the PCB.

    Unhappy!

    Like

      1. Jamie, double check the fuse. Over mine fuse power was going through but not fully…strange… on the first look the fuse doesn’t seemd to be blown, but it was.

        Like

    1. The fuses fitted to the board can be found here: http://uk.rs-online.com/web/p/non-resettable-surface-mount-fuses/7368757/.

      However, you need to be reasonably skilled at soldering otherwise you will lift the copper tracks from the circuit board. Others have used wire-ended fuses and I got a pack of these: http://uk.rs-online.com/web/p/non-resettable-wire-ended-fuses/7649508/ but they were not needed.

      Both of these are ‘low voltage’ fuses and not suitable for utility power voltages but are perfectly OK at the battery voltages.

      I do wish my problem was just needing a fuse change!!

      Like

      1. Thank you for reply.
        I have question for you. I suffered same problem ‘power out’ and also LED flash,because hard breaking. Did you solve this problem?

        Like

      2. I have the new firmware 1.3.1 and was not braking when the power failed. In fact, I was going slowly up a steep hill and the motor was working very hard. Now I see no LEDs lit at all except 4 brief flashes in red when I connect charger or press reset button.

        I have the circuit board on the bench and I see that I have TWO Z fuses but neither has blown.

        Like

  7. Bonjour,
    J’ai le même problème que Peter.
    Et j’attends une réponse du revendeur qui me renvoie à ce site.
    Quelle solution dans ce cas?
    Merci
    Isabelle

    Like

  8. Xiaomi global customer service has been very polite but also unhelpful. Because they do not sell the scooter in Europe, they will not tell me how I can get it repaired; they will not sell me spare parts and they will not give me access to service manuals or circuit diagrams.

    Instead, they direct me back to the seller in China but I cannot send the scooter back due to recent EU legislation that classes Lithium Ion batteries of over 100 watt hours as “dangerous goods”. DHL said it was absolutely forbidden to send Lithium batteries to China. It is not clear why batteries can be sent FROM China to Europe.

    I am now working on replacing the large MOSFET chip which is type MDE1932 and made by Magnachip. So far, I have not found a replacement for this apart from one which is physically bigger but electrically the same. I will get one of these to see if the blue light will come back on.

    I will update this thread when I get the result.

    Like

    1. OK, the blue light is back on. That wasn’t a job for the faint-hearted or those not reasonably skilled with a soldering iron.

      I replaced all of the power components on the Battery Management System printed circuit board. The reasoning behind this was to cause minimum stress to the copper tracks because the PCB is irreplaceable while the components are cheap.

      The first thing to do was to identify the components. If you are an electronics engineer, the following description will mean something to you:

      Q8 is the big MOSFET in a TO-263 package and it is an MDE1932
      Q7 and Q9 are the smaller MOSFETs (TO-252) and are MDD1902
      D9 is a Schottky common cathode diode (TO-252), part number MBRD10100CT

      The BMS chip is a BQ7693003 and the microprocessor is STM8L151K6. I did not replace these two tiny chips; they are beyond my skill and have been customized.

      I had to use equivalents for the power components because suppliers wanted me to buy a minimum quantity of 2500 of the proper ones.
      Instead of the MDE1932, I used an Infineon 120 amp MOSFET, part number: IPB038N12N3.
      Instead of the two MDD1902 40 amp MOSFETs, I used MDD1903s and I only had to buy 25!
      Instead of the Schottky double diode, I used SBR10120CTL which I only had to buy 10!

      Some words of advice when removing the old components: Do not try to get them off whole. Cut the pins so that you only have to desolder the big drain of the MOSFETs and later remove the remainder of the source and gate connections. Again, this is to minimize damage to the PCB.

      Having replaced the components, I cleaned off the excess flux with isopropyl alcohol and re-assembled, connecting the cell balancing connector and the thick black wire that I had removed in order to disconnect all power while re-working the PCB. After the red LED flashed a couple of times, the blue LED started flashing and I cheered! I had made a bit of a mess removing the plastic shield so I shall have to find some other way of protecting the battery assembly.

      I re-fitted the battery to the scooter and was pleased when it all worked. The blue LED flashes faster when the motor is running and I had a moment’s panic when the red LED came on while charging but this seems to be normal.

      I don’t know for sure which component was faulty but I believe it to be Q7. It’s difficult to test MOSFETS on a PCB but quite easy when they’re not connected. Q7 was the only one that wouldn’t turn on but I may have damaged it in removing it from the PCB.

      Anyway, as of now, the scooter is repaired. Let’s see how long it will last!!

      Please ask if you have any questions.

      Like

      1. hello peter, how many volts did you have at the exit of the card? and to the output of the battery? to me I get 40v from the battery and 20 from the bms …

        Like

      2. Carlos, if the BMS card is satisfied that the battery is OK and all the cells are reading the right voltages, it will effectively just throw a switch so that the battery voltage appears on the black connector, i.e. you should see the same 40v for a fully charged battery.

        If you don’t see this, then something is wrong. Yes, it could be a faulty BMS board but is far, far more likely to be one of the sense connections monitoring the cells through the ribbon cable. Give each tag a good tug with a screwdriver and see if any come loose. Having said that, I have had two instances where the connection has broken where the tab has been bent at 90 degrees and has weakened the nickel strip. In this case, you have to remove the black plastic cover which is just stuck on and resolder. I used a short piece of thick copper wire to strengthen the connection.

        I now have three separate batteries and they have ALL failed in multiple places. Is this my fault for using a solid tyre at the back in place of the inner tube that splits so easily. The front tyre has never punctured.

        Like

  9. I have the same problem. I used scooter for half a year without a problem (around 200km), than upgraded to FW 1.3.1 and after 3km of driving at the last braking from 10km to 0kmh the scooter powered itself down. Battery was on 40%. I hope only the fuse is problematic. Peter I hope you will stay online if I will have questions for you when repairing or a connection to you?

    Like

  10. I have a question.
    My charger dosen’t work…
    When I open the scooter, BMS state is only blue light with no flash. Could you answer this state or solve this problem? 😦

    Like

    1. Yes, one of the battery welded connections has come loose and you will have to solder it. See the second case at the top of this blog.

      You may see that the number of lights on the control panel shows a low charge in the battery but the cells that are still connected are fully charged so the blue light is on steady and the charger light is green. When you have reconnected the broken connection, the blue light will flash and the charger light will go red.

      Like

  11. Also, my mijia 2 BMS damaged. But everything is fine except BMS.
    I’d like to change BMS board.. Anyone know where I can buy new BMS board?

    Like

  12. Hey guys I was reading your advices, I kind of have a different problem. I can turn on the scooter, but only first light is blinking, and it doesn’t give me the full speed.

    I also opened the case, and see inside blue light is blinking. Does anyone know how to fix this?

    Like

    1. Nick, do you get a red or a green light on the charger when it is plugged in to the scooter? If you try charging when the case is open, does the blinking blue light change to red?

      Like

      1. Now yes when I took off the wires and put them back. It seems like I fixed the problem, but is it gonna appear the same problem?

        Like

    2. Here’s another item to add to the knowledge base. I found that I could not charge the battery, even though it was half empty. The light on the charger was green and when I opened the case the battery light was flashing blue. OK, I thought, we have a faulty charger or connection but it all tested good.

      I then pressed the battery reset button, near the blue LED and the red LED started flashing and the charger showed a red light as the battery resumed charging.

      Looks like the microprocessor on the BMS needed rebooting.

      Like

  13. Everyone should try upgrading the BMS firmware to v1.1.5. I don’t know what problems it fixes but I have updated two batteries and they both work well.

    Like

  14. Hi guys, I have a completely different problem.

    M365 came today, unpacked it, found scratches? Did this happen to you too?

    The dramatic part is that the engine never started when pressing the handle, it never ignited. I’ve tried point 1) in the blog, no luck. Just to be clear, I can chargebit, I can open the lights just that the engine won’t start.

    Ever came across this problem?

    Like

  15. Just sharing my experience in case will help someone. Yesterday while trying to start my scooter I noticed that the leds are not lighting up and scooter won’t start. After a bit of research I came across this website and by following the 1 step I open the battery cover and checked for any internal damage. While I try to unplug and plug back the cables nothing happend. Connecting the charger I noticed that the blue led on the battery ( as some videos on YouTube show ) was not flashing but instead a red led light flasing 4 times and stop, maybe some error code.

    Following the step 2 I found that one of the connector was desoldered, as shown in the image on step 2. So I open carefully the plastic around it and soldered the connector and now all is fine working again. I believe that this happens due to changing the tires to tubeless ones which produced more vibration. Just a guess. Well, that’s my story hope it will help others. Many thanx to the one that took time to put together this tutorials and steps.

    Like

  16. Hi again!
    I let the unofficial service to repair my blown fuse Z. The Z fuse was upgraded with additional cable and connector for car fuses. The fuse i can change now myself if that happens again. I am now using 15A fuse and the scooter works like before.

    Like

  17. Changes to my post on 30.7.2017.
    I upgraded from 1.2.9 to 1.3.0 and not to 1.3.1.
    Ninebot 4.0 app shows now 1.3.0 as the latest. The app suggested me to update the BMS to 1.1.5 which I did now after the fuse repair.

    Like

  18. can anyone tell me what each of the flashing lights signify please?

    i’ve had it constantly flash red, switch between blue and red (sometimes alternating, sometimes random), 4 red flashes and just nothing.

    i’ve checked the fuses and temp sensor and they are working fine, and depending on the state of the lights power does come through into the cables which attach to the other board. all wires on the battery controller seem to be ok too.

    the lights sometimes jump into action when the controller is removed from the casing, and then when moved further or placed back inside it cuts out again (this does suggest wiring, but everything seems to be ok)

    does this sound like i will have to replace all of those other components on the board? i’m beginning to think so, but would like a second opinion before i jump into it.

    thank you for your help, jamie

    Like

    1. Jamie, before you start changing all the power components on the BMS circuit board, check really carefully that there isn’t a loose battery tab as shown in option 2 at the top of this this thread.

      The intermittency and variability of the symptoms you are experiencing suggests to me that it will be a loose connection somewhere and the poor welding of the battery tabs seems to me to be the most likely culprit.

      Like

      1. thank you for the reply peter.

        i thought i had checked the tabs, and upon a closer inspection (gently wedging some card between them) i noticed that one tab had come loose, so cheers for that recommendation!
        though i am still not getting anything other than nothing, or the 4 single flashes. sometimes i get the double red flashes, with the odd blue, but this is quite rare.

        there is power coming from the main battery battery power connections, it’s just when testing the shorter power cables that there is next to nothing coming through.

        what should the reading of the components such as the temp sensor and the z fuse be? i’m wondering if i’m reading them wrong or something?

        also, is there a way to test that the ribbon connector from the battery to the controller is working ok? it seems that a lot of activity happens when this is being moved.

        thank you for your help.

        Like

      2. Jamie, I still think you’ve got one or more dodgy battery tabs. The sequences of lights match what I had this morning when, having ridden to work, I couldn’t power up to come home.

        When I pressed the little reset button on the BMS board, the blue light would come on for a short while, then flash the red light after which all lights would go out. The tabs looked OK but I bent up the outside edge of each in order to get a good place to solder. As many will have found out, it’s difficult to ‘wet’ nickel with tin solder and an aggressive flux is need after giving the surfaces a good scraping with a scalpel.

        This battery design is really not suitable for an environment where such vibration will occur as the scooter is ridden over bumps. The cells are heavy and exert big forces on those six tiny spot welds. I have now prised apart all mine and resoldered them and I’m mobile again.

        I’m coming around to the point of view that all faults are due to battery connections apart from the well-known Z fuse problem on regenerative braking. There is a huge variety of symptoms depending on which tab or tabs are not making connection.

        It’s interesting to note that the microprocessor and BMS chip seem to get their power via the ribbon cable rather than the thick black and red wire because even with these disconnected, the microprocessor responds to reset and other anomalies.

        I suggest you emulate a very bumpy ride and pull at the tabs with moderate force using a small screwdriver and see if any more come off. After all, it’s better that they come apart while you’re at home rather than out riding. You can then solder them back but try not to use a blob of solder on the surface which will result in a ‘dry’ joint. The solder needs to flow over the surface.

        TO answer your question about the lights: the blue light on steady means the battery is fully charged (but can mean only some cells are fully charged and the there is a broken connection). The blue light flashing slowly, once a second, is normal in the idle state. The blue light flashed fast when the battery is discharging, i.e. the scooter is powered up and/or running. The red light flashes once a second while the battery is charging and flashes at other times to indicate a fault such as a broken connection.

        And then, to complicate matters even further, different symptoms occur depending on which connector is broken and if there are more than one broken.

        It’s all very poor mechanical design and not fit for purpose.

        Like

    2. Just another thought, Jamie. After you fixed the latest loose tab, you did press the reset button to reboot the microprocessor, didn’t you?

      Like

    1. Gianluca, you can see the voltages of each of the 10 cell assemblies using the MiHome android app. This also shows how many charge cycles the battery has been through.

      Like

  19. Hi again,
    Today after very hard braking the 15A fuse has blown again. FW 1.3.0 and BMS 1.1.5.
    I changed the fuse to a new one, but scooter still doesn’t power on.
    Blue light is flashing 1x per second, I can charge the battery, the LED on the BMS is red and also on the charger when charging. It looks all OK but no power on. The battery shows 36.1V what seems normal.
    What should I check now?

    I suggest not to upgrade firmware from 1.2.9 to 1.3.0. as on 1.2.9 I had no problems for half a year even with hard braking.

    Like

  20. Ok, so I have a diagnosis for my own one.

    Symptoms:
    Randomly stopped working, opened twice and done the first, that worked a bit, but stopped on the next two big rides.

    Noticed one cell voltage was down in the app.

    Next time.i opened after fail, blinking flashing red light four times.

    Solution:

    Pressed the reset button (on the edge near the lights, while.pressing the contacts down, resetting after each time.

    I isolated the dodgy connection (plus one semi loose) and managed to get a flashing blue light

    Next step: solder the connection. Pressing down the dodgy connector, it would charge and turn on.

    Like

    1. Thank you.
      My scooter often stops to work and doesn’t want to switch on; i usually habe to plug it to switch on. Sometimes not even plugging. I did follow the first case and it switched on bit the batttery looks crazy changing level of charge. Can you explain me how to check single battery cells. I did it once via ninebot but I think I have a new version of it and can’t find the way.
      Thank you

      Like

  21. I have the same problem . 4 blinking red. Its started when i change my tire with a solid rubber and when i upgrade to the latest firmware And i dont know what to do. I read peter post but the electrical engineering term i cant understand. Please can you make an article how to fix this with photos for easier to understand.

    Like

    1. Manuel, I would strongly expect you to have a loose battery connector as in case 2 above. Using solid tyres increases the vibration and shakes the connections apart. You will have to cut off the plastic case from the battery and solder any of the 10 connections that have come loose. Afterwards, press the little reset button by the blue LED to reboot. Bear in mind you may have more than one loose.

      Like

  22. Peter thanks bro my battery is good again . yes peter is correct double check the connections . because of bumps the stamped contact snaps easily its better to re enforced it with soldering iron.

    Like

  23. Hey everyone, a month ago I had a problem with the battery, completed 2nd step and everything was fine. But then it happened again.

    Even if when I start my scooter, only one light is blinking out of four, I am able to drive it, but it is really slow.

    I tried to repeat again the 2nd step, but unfortunately no success.

    It seems to ignite (I guess no need to change the fuse) works because I am able to drive it only on the one light which is blinking out of 4.

    Did anyone have this experience solved?

    Like

    1. Nick, I’ve done a lot of work in reverse engineering the BMS control board and I will be publishing an article about this later.

      Meanwhile, I can say that there are only three possibilities for your problem:
      1. The battery is not charging. To determine this, see if the charger light is red and the little LED on the BMS board is flashing red. If the charger light is green and the LED is flashing blue, then there is a problem with the charger circuitry.
      2. If the charger light is green and the LED is solid blue, then you have a disconnected battery tab as in 2 above. Give each tab a good pull with a small screwdriver and see if another one will come off and needs soldering. Check your previous soldered connection because it’s difficult to make a good connection to nickel. Make sure the solder flows and does not ‘blob’
      3. If you have had the BMS board out, check that the ribbon cable connector is properly pushed into its socket. It does need to be fully home so that all 11 connections to the battery can be monitored properly

      If there are still problems, please say what LEDs are on the BMS board (red, blue, flashing. steady) with the charger plugged in and disconnected and what the color of the charger light is.

      Like

  24. Hi Peter, I have a similar problem. 4 red flash, after reset 4 red flashes again. No charge (green flash on the charger and red flash on the board. I hope that this is a fuse problem because I cannot understand your expert description and I cannot change anything else. Maybe I should find somebody to fix it. Do you think that the fuse has blown? I am waiting for your article.

    Like

    1. That’s definitely a battery connection problem as described in the 2nd case at the top of this blog. If you feel confident in soldering a replacement fuse to the BMS board, then fixing this is easier.

      Cut along the plastic covering and remove it. There are 11 connectors such as those circled in red in the photo. Pull up on each one with a small screwdriver and see if any are loose. Start with the one nearest the back wheel. If you find one that is not connected, use a soldering iron with plenty of ‘flux’ to re-connect it. Although you need to get solder under the tab, do not bend it too much because nickel is more fragile than copper and it may snap off or break next time you ride over rough ground.

      After you have found and fixed (all) the loose connection(s), you may have to press the very small reset button on the BMS circuit board that is right next to the LED that flashes. Once you do this, the blue LED should be flashing at 1 second intervals.

      Good luck!

      Like

  25. mi problema es el siguiente, soldando una patilla de la batería hice un cortocircuito el cual dejó mi placa bms con 20v de salida, los led todos apagados, cuando presiono el boton reset no hace nada, si conecto el cargador no hace nada y el led del cargador está en verde siempre, no se enciende el patín ni hace nada, está muerto. Después de comprobar la tarjeta voy a cambiar este chip integrado:

    https://fr.aliexpress.com/item/Free-shipping-BQ7693003DBTR-7693003-TSSOP30/32763224627.html?spm=a2g0s.9042311.0.0.BFsDkp

    además voy a cambiar los 4 transistores que dices en el hilo Peter…

    tienes transistores de sobra en tu casa? te interesa comportirlos? te puedo comprar la mitad de los que tienes, yo vivo en españa. De todas formas ya tengo pedidos todos en una tienda de electronica y aliexpress, por cierto este tambien lo encontré en aliexpress,

    https://fr.aliexpress.com/item/Free-shipping-10pcs-lot-MDD1902RH-MDD1902-TO-252-laptop-chip-new-original/32688497256.html?spm=a2g0s.9042311.0.0.xOZhrh

    Like

    1. Carlos, please excuse my reply in English.

      Before doing anything else, could you look very carefully at the LEDs when you press the reset button or connect the charger to see if you get 4 quick flashes of the red LED? If you do, then the CPU is running and you probably still have a broken connection. If there are no red flashes, then it’s a serious problem.

      I would advise against changing the BQ76930 battery management chip for two reasons:
      1. It is VERY difficult to unsolder the old one without what is known as an “SMD Re-work station” which uses hot air to melt the solder just where heat is needed. If you use a regular soldering iron, you will damage the very fine copper tracks underneath this tiny device.
      2. These chips are pre-programmed with data held in certain registers. Some of this programming is done by TI during manufacture and some can be done by the assembly plant using specialist equipment. See the data sheet at http://www.ti.com/lit/ds/symlink/bq76940.pdf for full details. Therefore, it is unlikely that chips bought from aliexpress would work without this programming.

      I suggest you look VERY carefully to see if there are any other broken links from the battery to the ribbon cable. To do this, you may need to unsolder the thick black wire from the battery and remove the black plastic covers on each side. Then, look carefully to see if you have broken any of the nickel strips where they bend over the edge. It’s easy to break these when re-soldering if you lift the tab too far to get the solder underneath.

      Let me know how you get on.

      Like

  26. Hi folks, this is my issue. Scooter runs ok and randomly once per day stops, I hear one long beep and 3 short ones. What I usually do is to desconnect the battery and connect it again, about 6 to ten times and the scooter ‘starts’ again.
    I didn’t know that there was a reset button.
    When the scooter fails, the nine boot app shows zero battery (when actually could have 70%). Always I have a blue light in the BMS (blinking 1 per sec). I checked carefully the battery connectors and are fine. Scooter is from March 2017. Thanks for any clue you may issue.

    Like

    1. Marce, This is no more than a guess but based on what happened when I tried using a different battery:

      Are you sure that the plug with the yellow, green and white wires is properly connected to the controller board? This enables the battery pack to ‘talk’ to the controller and the battery will appear to be at zero if it cannot tell the controller.

      Like

      1. Hi Peter,
        I double checked the cables plug and these are OK. One thing to notice is that when the scooter is turned on and running well, i got the blue light flashing from the battery pack, one per second (I think this is controller board) but from the BMS (like a transparent box) I have a red light (no flashing). Is this ok to have this colour (red) or should be blue as well? tks!

        Like

    2. Marce, I think we may be getting confused. The blue LED that flashes once per second is on the battery pack and is part of the Battery Management System (BMS). The red LED that is on steadily when the scooter is on, under the transparent cover, is on the controller board with lots of connectors.

      As far as I can see, the lights on the battery pack (BMS) behave as follows:
      * Blue light flashing once per second: This is normal when the battery is working properly but neither supplying power, nor being charged.
      * Blue light flashing faster: The battery pack is supply power to the scooter (scooter on)
      * Blue light on steady: The battery is fully charged. But this can also mean that the BMS thinks that one or more cells are fully charged and can indicate a broken battery sense tab.
      * Red light on steady and blue light off: This is normal when the battery is being charged
      * Red light flashing or four flashes then off: This indicates an error – probably with one or more of the battery sense tabs coming loose. The four flashes will happen when the reset button on the BMS board is pressed, or the charger is connected.

      There seems to be two LEDs on the controller board:
      * A red light which comes on steady when the scooter is powered on and is off when the scooter is off.
      * A green light which is on (and there is a bleeping sound) when the controller board can’t communicate with the BMS. This probably means that the connector with the green, yellow and white wires is disconnected.

      Back to your original problem: It sounds as though the battery is OK unless the green/yellow/white cable has a poor connection. What I would do is remove the controller board, carefully noting where the three big wires to the motor are connected – and look for bad soldered joints.

      When the scooter stops, do you see any LEDs alight on the controller board under the transparent cover?

      Like

  27. Hi people,
    I have an issue that has not been stated here yet, hopefully somebody can help me.
    My scooter arrived a little scrached and the main issue is, that it won’t start. It does charge, the battery port has 40.5 Volts (so battery tabs and z-fuse should be fine) and when I press the power button the main board led lights up in red while another led on the same bord blinks in blue (break light blinks at the same time).

    Now the weird thing is that after storing the scooter for 2 weeks, it did start up (battery indication next to the power button was on), but the acceleration did not work and after 1 minute it was not possible to turn on the scooter again.

    So may it be a loose connection? If yes, where is it likely to be?

    Like

    1. Again, check the cable from the battery to the main controller board with the green, white and yellow wires. The plug is supposed to be held in with a sealant but it’s worth wiggling it to see if it’s loose. If this is the problem, then there should be bleeping from the controller board as well as the flashing blue light. [Note to everyone else: do not get this blue light on the controller board confused with the normal blue blinking LED on the BMS board]

      Like

  28. It seems to be a loose connection as far as I can tell. If I twist the cable coming from the handle bar at a certain point, I am able to power on the scooter, but not to accelerate. Anyone can help me out? And also whereabouts to buy a spare cable?

    Appreciate your help 🙂

    Like

    1. Bategoikoe, is that green light the one at the bottom of the row of four on the handlebars, or is it the green LED on the controller board next to the battery pack?

      If it’s the one underneath near the battery, then it means a communication error. This can be communications from the controller board to the battery (the three pin connector with green yellow and white wires), or the communications with the handlebar electronics which is the four pin connector. Check that these are plugged in fully.

      When you received the scooter, you will have had to insert 4 screws to hold the handlebars to the column. You will need to unscrew these again and check that the four-pin connector inside the black tubing inside is properly connected and that the cable hasn’t been damaged – for instance by the screws! Just like cczapkaChris above.

      Like

      1. Here is video of the issue. I’ve checked 4pin connector it seems perfect.
        I really suspect battery controller board. Cause at first I had bad connection and I soldered all battery pins.
        Another issue is that when I fully charge battery it blinkes red, I need to reconnect serial connector to be blue again.
        https://photos.app.goo.gl/XwwwaIUSAkO9pWUm1

        Like

      2. I can see from your video that, when you power up the scooter, the red LED on the battery pack lights. This seems to indicate that the problem is between the controller board and the battery pack. Difficult to know what to advise from here other than a VERY careful check of any damage you might have done to the battery pack when you soldered the pins.

        You say you get battery data via BT. Are you using MiHome or Ninebot? With MiHome you can see all the battery cell voltages. Are they all equal?

        Sorry I can’t be of more help.

        Like

      3. Thank you very much for your prompt answer

        Last update. When I start it without 3 pin connector it beeps 2long 1short and on MiHome there is no data for battery. When I connect 3 pin connector, blue light on the battery becomes red, beeps becomes 2long 2short and on Mi Home I can see all the data for the battery biggest difference between cells is 0.02v

        I’m totally stuck, all the battery sensors respond, the only thing is that I lost my tail light and this is the only thing that I haven’t checked. Maybe it’s possible that this malfunction could cause it, but in the past it never has been a problem. I’ve lost it 2 months ago.

        Like

  29. Hello,
    After opening my battery, I get 40V on at the output of the battery, but only 20V at the output of the BMS.
    Is anyone had already the same issue, and fixed it?

    Is there anything on the ribbon cable ? How could I check it?

    I do not think it is the Z fuse as I have 20V!

    Thank you,

    Like

    1. At the risk of sounding repetitive, this is almost certainly a battery connection as in option 2 at the top of this discussion. It’s important to remember that these connections are only for monitoring the cell voltages and do not affect the actual 40v output from the battery for the main traction current supply. So, yes, it’s the ribbon cable, or rather the connections to the battery from the ribbon cable.

      If one of these connections is broken, the BMS will think that there is a battery fault and (partially) shut down the output even though it has a good 40v input.. The connection that usually lifts first is the one nearest the back wheel but you should check them all while you have the plastic covering off.

      If your scooter will power up at all, the way to check is to install the MiHome app from where you can monitor all the cell pack voltages. If you see one higher than the others and one lower than the others next to it, then that identifies which connection has come loose.

      Hope this helps

      Like

      1. You have right, the connection nearest the back wheel is lifted up. I will solder it and try to follow your procedure.
        I thought that the battery output voltage would depends on these connection, that is why I didn’t try the option 2. Thank you for your explanation, that is very clear.

        Like

      2. Hi, scooter works now! because of you! so I would like to thank you so much.
        It was the connection lifted up.

        For information, I also changed the rear wheel by a solid one, and I never punctered the front tire. Scooter has now 300km of mileage.

        Like

    1. The battery may have 34v measured at the thick black and red wires but if the cell monitoring connections (which are the 11 connections via the tabs shown in option 2) are not connected, then the BMS may not light any LEDs. You can tell this by connecting the charger and you may see the red LED flash four times and then stop.

      You should remove the plastic covering and check all the tabs as in option 2 and resolder any that have come loose. Then press the little reset button that is by the blue LED and all should be well.

      The first time mine went wrong, I fell into the same trap of thinking that all those tabs must be OK if I had full battery voltage on the thick black and red wires. The tabs are ONLY for monitoring the cell voltages and do not carry the power to the motor. If the BMS thinks that one or more cells are wrong, then it will shut down.

      Like

      1. OK, I’ll check it later. Someone does it for me.
        But when I plugged the charger before, it lit up green. And the other diodes were not lit on (BMS and controller).

        Like

      2. Hi, I checked all the connections. They were soldered. But still nothing happens when the charger is inserted. No LED is on. There is only green light on the charger.

        Like

      3. Tomasz, the next step is to measure the voltages at each of the connections tabs circled in red in the photo at the top of this thread. There are 11 of them, labelled B0, B1, B2 through to B10. Connect the negative wire of your voltmeter to the thick black soldered connection on the side of the battery and then measure the voltages which, assuming your battery voltage is still 34v, should be as follows:
        B0 – 0v
        B1 – 3.4v
        B2 – 6.8v
        B3 – 10.2v
        B4 – 13.6v
        B5 – 17v
        B6 – 20.4v
        B7 – 23.8v
        B8 – 27.2v
        B9 – 30.6v
        B10 – 34v

        If any of these readings are more than 0.02 different, then you have a problem and it is possible to guide you further once I know which connection(s) are different.

        Peter

        Like

      4. Hey,
        I checked and the results are as follows:
        B0 – 0
        B1 – 0.55
        B2 – 3.98
        B3 – 7.43
        B4 – 10.88
        B5 – 14.33
        B6 – 17.78
        B7 – 21.0
        B8 – 24.5
        B9 – 28.0
        B10 – 31.4

        Like

      5. OK, Tomasz. Now peel off the black strip of plastic on the side of the battery next to B1 and look very carefully at the connections from B1 to the six battery cells. I suspect that you will find it cracked and not making connection, even if the tab welds are still OK on the top of the battery. Pull it with a small screwdriver and see if you can find the loose connection there.

        If you find that the strip of nickel from B1 to the battery is broken, then solder it together and replace the sticky black plastic strip.

        Good luck.

        Like

      6. Thanks for the quick reply.
        I took off the black plastic. I checked all 6 connections and they seem to be ok. I tried to pull it them but they hold batteries very tight. Do you have any idea what else I can check?

        Like

      7. I still think it’s going to be a connection problem but you seem to have checked everything. It just could be one or more faulty cells but that’s rather unlikely.

        If you can find a way of shipping the battery to me in the UK legally (it can’t go by air) and having it collected from me afterwards, I will try to repair it, make it more resilient to these connection problems, test it and put new shrink tubing on it. There will be no charge but you must take responsibility for the transport both ways.

        Like

      8. Ok, one person in my city, wants to help me. I will give him all the information I got from you. If we cannot solve this problem, I’ll talk to you to send the battery.

        For now i want realy thank you.

        Like

  30. Reparación de la Batería: Debido a las vibraciones las placas que unen las celdas de la batería se parten, de forma que hacen contacto cuando quieren. Por lo tanto el BMS corta la alimentación cuando le apetece. Adjunto el vídeo de como estaban las placas partidas y como ha quedado tras su soldadura. Ya sabéis , además de revisar las pestañas, revisar las placas partidas, yo las tenía partidas en los dos laterales. Espero que os sirva. Aquí el enlace:

    Like

      1. Hola, primero debo decir que la soldadura a las células de la batería no es ideal porque el calor no es bueno para la batería. Sin embargo, no muchos de nosotros tenemos acceso a un soldador de punto para hacer el trabajo correctamente así que tenemos que usar soldadura.

        Lo primero es quitar el óxido de la superficie de la célula y de la tira de níquel que los conecta. Idealmente, usted debe quitar el óxido de níquel con un producto como Citranox que está disponible en Amazon, pero yo uso un cuchillo pequeño o abrasivo ‘Emery’ tela.

        Ahora aplique un “flux” agresivo como ZJ-18 que también está disponible en Amazon y en otros lugares. El uso de un soldador caliente y bastante grande calentar rápidamente las superficies y ‘estaño’, la fusión de la soldadura sobre las piezas a unirse. Esta soldadura debe fluir suavemente y no formar gotas. Una vez que ambas superficies estén correctamente estañadas, entonces manténgalas juntas y vuelva a aplicar el hierro de soldar para fundir la soldadura y unir las superficies. Una vez más, usted debe trabajar rápidamente. Mantenga las superficies juntas durante unos momentos para dejar que la soldadura se enfríe y limpie el exceso de fundente con alcohol isopropílico.

        ¡Trabajo hecho! [Traducción del inglés de Google, así que espero que tenga sentido!]

        Like

  31. hello everyone, my scooter wont turn on after hard brake, its just 2 days using it… the store help me change to new battery pack… im afraid if i make hard brake again it wont turn on again… my question is:
    1. is hard braking is the main problem of this scooter? so if I’m not using the brake it will long last?
    2. or after following all the step at the top of this page, it will be no problem with hard braking?
    3. any suggestion using this scooter so that problem wont happen again, example not using hard brake.

    thank you before, need an answer.

    Like

    1. No, the cell pack voltages as shown on the MiHome app should be within 0.02 volt of each other, except when they’re nearly discharged.

      If you have one higher than the rest and the next one to it is lower than the other 8, then one of the battery sensing tabs has lifted and it’s the one between the two abnormal values.

      If just one cell pack has a lower voltage than the other 9, then one of the three cells in parallel in that cell pack has come disconnected so the remaining two cells are trying to do the work of three and running down quicker. In either case, you will need to open the battery pack and re-make the connections.

      Like

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