Electric Scooter Forum for Scooter Enthusiasts, Scooter Chargers, and Scooter Mechanics.

Discuss the Xiaomi mijia mi M365 original and pro versions in this forum. Topics include hardware, software, hacking, riding, and everything in between.
By michi_gecko
Posts
#11839
Hello,

For two weeks I have the M365 PRO Scooter, which is really nice.
But I experience two Problems or strange behaviour.

1. Error 40:
Seems to be quite rare, because there is not much to find over Google.
After going uphill in "S" Mode (sometimes also "D") this error jumps in very soon.
The Display shows the "40" in red, and the scooter stops. If turned off and on again, I can continue driving at once.
The App says Case Temperature above 90 Degrees Celcius which equals to 194 Degrees Farenheit.
BUT, it does not seem so hot really. It feels a little bit warmer than my hand.

2. Battery Status:
The Battery seems to regenerate. After driving 2 Miles I get a reading of e.g. 60 %.
But I can see the mAh count going up while standing. It even went up, when I had the Wheel spinning in the air.
After maybe 1-2 hours the reading says minimum 5 % more, than after I have stopped. Sometimes even 10-15 % more.

So my question: Is that normal? Doesnt seem so to me.
Should I send it back, or try to fix it by myself?

In general: How is the quality of new Xiaomi Scooters?
#12299
Hi am having a mi scooter pro, it's less than one month, am facing connection issues with my mi home app & dashboard is not showing Bluetooth option. Did you faced any such issues. I think for your issue try to adjust the app settings, use regeneration to the lowest in the app & try using only one mode, I only use sport mode. Then turn on cruise control it also helps reduce motor heating by keeping a steady speed.
#12338
Hi,

Regarding 1:
No, it is not normal at all. When you say that it does not feel hot on touch, do you mean the motor ? Because the error refers to the controller, which is located inside the scooter body, next to the battery. Such a high temperature after such a short ride is very alarming and can lead to fire inside the battery compartment. Therefore I would suggest to take it to electrician and avoid using it meanwhile. The cause of this might be something very trivial and easy to fix. If I had to guess I would say that most probably it is caused by a loose electrical connection.

Regarding 2:
I'm not sure, seems alright to me. If you are worried about the battery, you can install M365 Tools on your phone and check the battery voltages. You need to watch for a pack that has very different voltage than all others, if you don't have such then it is all fine. Differences less than 0.01v are completely fine
#12345
Thanks for the information.
So if it is the controller I should find the Problem quite fast.
I only read that the Pro Model has a too low motor constant in S mode.

Is there anything that can be optimized on the board, like better cooling connection or re-soldering some contacts?
By michi_gecko
Posts
#12915
Finally I found the source of the problem & also the solution.

After removing the controller case I could already see the problem.
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The NTC/PTC (not sure what they use) was between the Transistor and the case. You could see from outside, that the transistor was not touching the case properly. Therefore the transistor had no proper cooling, and the sensor got high temperature.

After removing the plastic cover everything fell apart.
Then I applied some heat conductiv paste on the transistor heatspreaders.
Everything was then put to place. Also I added some foam tape, so that there is more pressure on top of the transistors. I hope the thermal transfer is better with this.
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During re-assembling the controller case I found out, that the place for the brake wire is not optimal. It gets pressed down by the controller case. Resulting in a not so good contact of the case to the scooter itself. Also another part for bad thermal transfer. Also I did not like it, that the cable was pressed down over the quite sharp hole.
So I moved the cable up. It now runs between the outside wall right under the charging port.
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Finally I removed the original heat conductive paste and replaced it with better one. Just enough so that there is contact everywhere.

As last step I gently squeezed the cable connectors, so that they sit firmly on the pins.
That seems to be a common problem with this type of connectors. They might get loose by vibration.
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The battery pack is quite improved to the standard M365. I was curious how it would look inside. But it seems that the casing is sealed, so I did not open it.
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Temperature is now much lower, and it seems to work much better now.
Still I believe that the controller reduces the power as soon as the temperature goes up. As a guess after reaching 40 Degrees Celcius.
But it could also be the effect of the lower voltage. In my short test run uphill I went 10% down to almost 40% charge.
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