Magic Pie 5 braking

[Dias]

Hello everyone!

I recently bought a MP 5, got it working (almost properly) but there are couple things Im a little disappointed about. First one consideres stock brake handles. Since they don't support hydraulic brakes I only installed my front brake and wanted MP electronic brake to be my rear one...what a mistake, I almost killed myself and crashed a car during a test ride (after 10m of trip). How does the brake work? It worked later when I was riding faster but in low speeds (approx <10 km/h) it does nothing - sometimes. TBH I like the strength of brake and everything, but I would like to know how to brake at low speeds or how to set it up properly to brake when I pull the handle, not when it wants to..

A little minus for the grip throttle and bluetooth app. I have the half throttle and I had to move the outer part of the grip further - "throttling" part was getting stuck. Android application is not connecting properly and requires turning off and on after pressing connect.

Not to be negative only, Im very satisfied with everything else, works like charm and I will recommend it.

[Socalbiker]

Not an expert but what I've learned w/ my mp5.

Doesn't brake when battery charge is full, braking becomes stronger as battery charge goes down. Doesn't work at slow speeds, probably because wheel isn't turning enough for the magnetic fields to work for braking. I kept my bicycles front brake hooked up independently, use it for braking at slow speeds, when battery charged and when I need extra stopping power. Have my rear brake hooked up to activate regen/motor braking, have rear brake adjusted 'loose' so I have to push for a ways before the bicycle brake engages. Since I usually charge my battery to 80% my regen/brake works from start of ride, however until I've burned a few amp-hours I'm extra cautious about relying on regen/brake.

[Bikemad]

Hi Dias andto the forum.

The regenerative braking function on the MP5 will only work when the speed is above ~6.5mph (~10.5km/h) with a 26" wheel and the regenerative braking is supposed to be used in addition to both of the conventional brakes, not instead of them.

On a long incline, if I keep the lever pulled in just enough to activate the regenerative braking, the bike will slow to about 3mph (~4.8km/h), the braking force then stops completely allowing the bike to speed up until it reaches about 6.5mph (~10.5km/h) when the regenerative braking force automatically cuts in again.
This on/off braking style will continue until the brake lever is released.

The regenerative braking effect can also vary at higher speeds dependant upon the battery voltage and its state of charge.
If the battery is fully charged, it is unable to receive the full regenerative energy without the risk of being overcharged, so the regenerative braking force is automatically reduced and will be less noticeable.
When the battery voltage begins to drop again, it is then able to absorb more power from the regenerative braking, which also produces stronger braking torque from the motor.

Basically, to brake at slow speeds you will need to use the bike's mechanical front and/or rear brakes.

Alan
 

[Dias]

Thanks for your replies guys, what you say correspond to what happened. I have read about people configuring their MP not to regen during braking. Any chance that turning the regen off would make the brake work in low speeds? Or is there a different reason (except the incompatibility with hydraulic brakes) why people turn it off? I know there are solutions for electro-hydraulic brakes but these are kinda expensive.

[NR]

The regen braking is just activated by a switch, you can add a switch as a button or do as I did, mount a small reed switch on the hydraulic brake and a magnet on the lever, which activate just before the brakes actually grips. This gives good control. Just my opinion ;-)

[Bikemad]

I have read about people configuring their MP not to regen during braking. Any chance that turning the regen off would make the brake work in low speeds? Or is there a different reason (except the incompatibility with hydraulic brakes) why people turn it off?

One reason for turning off regen completely is when you are using a low capacity homemade battery pack (using LiPo or LiFePO4 cells.) without any form of BMS to protect the battery from being overcharged or charged too quickly.
The high charge current (and high voltage) produced during high speed regenerative braking could otherwise cause serious damage to the battery's cells.

Another reason for turning off regen is to prevent the opposing forces from the motor drive and regenerative braking torque from loosening the axle by constantly trying to twist it backwards and forwards by applying the torque in opposite directions each time you accelerate and then brake.
If the regenerative braking is disabled, any strong torsional forces acting upon the axle are always being applied in the same direction (and only when the motor is under load) as no torsional force whatsoever is being transmitted through the axle assembly when using only the bike's mechanical brakes. 

Even if you have disabled the regenerative braking, you should still have both brake switches working so that pulling either brake will instantly disengage the cruise function and more importantly it will cut the motor power if the event of a throttle failure if the motor was stuck on full throttle. 

Not having the power cut-off feature working on both brakes would make the bike illegal in many countries and could potentially be very dangerous too.

Unfortunately, turning the regen off will still not allow the motor's electromagnetic dynamic braking effect to work at slow speeds.

Alan