An Electric Scooter Community on a Mission to Stamp out Transportation Mediocrity.

Discuss the Xiaomi mijia mi M365 original and pro versions in this forum. Topics include hardware, software, hacking, riding, and everything in between.
By Guirmod
#16649
Hello I'm new to this world of electric scooters and I would like to know how the Kers exactly works on this scooter, is it passive ? Like when you're going downhill, you release everything (brakes and accelerator) and it regens ? Or do you have to press the brake handle to activate it ?

I already burned 2 motor controllers because of that stupid feature, now I'm scared of taking big slopes. I red you could disable it with a custom firmware but you would still have the motor braking that you feel when you release everything and I don't understand how exactly can you still have the motor brake while not producing any electricity.

So please, what exactly am I supposed to do to avoid burning another controler ? I would like to be able to take big slopes and not risking burning my scooter (I already turned the energy regen on low in the app). Thanks a lot :D
By Hammer11
#16652
My best solution for the “Crispy Controller” is to limit what the motor is actually doing. The motor controller is only doing what we programmed it to do and the Majia is my favorite by far simply because it has the least amount of saftey perimeters. The rider has more control. Disabling the Kers takes the auto-braking away from the motor which means you’ll have to transfer more resistance to the rear to stop which warps the rear rotor and puts harder braking resistance on the front. Also braking with more force in rear gets a bit dangerous. I can ride a Lime V2 (Low Boy) harder because how much more effective it’s rear drum braking system is but when turning and braking its gonna power slide. A 60-40 front to rear weight braking force ratio works for me. Weight is the problem in the slopes. The M365 just wasn’t designed for hilly conditions, that’s where the M365 Pro takes over. Try this. Get the rear brake and rotor upgrade from the Pro and the adjust the brake so there’s barely enough drag on the rear to where it can free spin about a turn and a half with a lil push. It all depends on weight so you’ll have to adjust it more then once. Also you mentioned you replaced controller. Did you put electrical conductor grease on the back? That is key it transfers heat and makes for a good ground. Make sure to inspect the brake cable for any resistance with the caliper unattached. If it can’t move in and out freely won’t disengage correctly and stick. Check all electrical connections for any dirt or grease that may cause resistance and heat. And last but not least be aware of what’s your carrying with you. 220lbs total weight capacity. The controller won’t limit power if there is too much weight like the ES does it will just burn out
By Guirmod
#16682
Hi, thanks a lot for your reply 👍
I thought I mentionned it but my scooter is already a m365 PRO, that's why i'm a bit disappointed

I have several questions that seem to be unsolvable, everybody have a different version

- How is the regen braking activated ? Do I have to press the brake handle to activate it ? Or is it passive like for example I'm riding downhill, I release everything (accelerator and brake handle), does it regenerate with the resistance I feel in the front wheel ?

- If the brake handle activates regen, then it means there is a sensor in it somewhere, so what if I remove it ? Does it remove Kers ?

- If I disable Kers with a custom firmware by setting activation above 40km/h for example, will I still have the motor braking ? And if yes, will it generate energy ? So is it still dangerous for my controller ?

I'm scared of taking big slopes now, and I would like to be able to ride freely without worrying about it, I mean yes I understand that climbing big hills with heavy weight can be dangerous for the scooter but come on I broke my scooter TWICE on a downhill where the scooter has the less stress, gravity does everything !
By danc
#16707
In my readings it's the Pro version which burns out the controller (seems it's the same unit as fitted to the 365) without upgrades to the design /mosfets, for the slightly increased battery and motor.. it's proving inadequate to purpose.
Regen Seems as the issue.
Some have claimed better heatsinking of the controller mosfets is the Solution.
Personally I doubt it ..as the oem heatsinking is not easily improved on.
Setting regen to weak is imo Mandatory (disabling could be even better imo)
But that does raise the need for better actual braking issue.
Rear pro discs are like 5$ to buy. Although Warpage is due do the crap quality cable operated caliper (although careful periodic adjustment Helps)
A hydraulic setup is far more capable/reliable and easily done.. affordable but not oem quality free either.
Then one is into the brake being on the wrong wheel (weight transfer).. as lockups and sliding can be an issue in heavy brakings. Aided and abetted by the Kiddie Stroller tires fitted... these Ain't pirellis :-)
Alternate and IMO ideal improvement would be to swap wheels.. Place the braking wheel where it's effective.
Disc at front ...Motor at the back. Looking to me like a plausible and possible mod (I needs do) as well.
OR hope and pray Xiaomi will recal/upgrade their Faulty controllers.
A Seriously uncarachteristic/ unlikely event IMO
By Guirmod
#16713
What do you think about that :
Someone suggested me to put a 2nd brake handle (on the right) and link it to the brake cable so it is a 100% mechanical brake with no sensor at all, therefore leaving Kers deactivated. Of course the left handle would be useless but would still have the sensor in it so if I want to activate Kers while braking I can do it by pressing both handles at the same time
By Sleepycat3
#16730
As the mosfet is frying, causing a short and crispy controller, it would be better to determine the failure mode. If the source and drain pins shorted, then the motor would run constantly. I wonder if the back end coming through the drain during regeneration is is punching through to the gate of the mosfet. Going to put on gate resistors (easy) and figure out how to add on free wheel diodes to the board (not trivial).
By Otto
#16972
IMO disabling the KERS is not the solution, since this allows you to go 40+ kph and then when you touch the brake it instantly fries the controller. Don't ask how I know that :roll:

Is it possible to reduce the risk by charging "Parameters for brake lever"?
Maybe drastically reducing both minimum and maximum phase current?

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