Bafang Max Drive - configuring

[smov]

I would test changing the spd0 and see if it applies to both sport/eco. My guess is it will apply to both, with eco being some % transformation of sport. If not then I would guess sport is whatever torque settings you program on the controller, and eco is a separate torque setting that can't be programmed.

Found the same: Eco mode is not affected by changes in the torque settings, see here:https://endless-sphere.com/forums/viewtopic.php?f=28&t=99669&p=1542021#p1542021

 

[Letterman]

Here's another potentially silly question:
I'm trying to effecitvely limit the top speed for each of the 9 assistance levels.
Obviously this can't be done through the speed sensor settings, as there is only one true speed limit, set in the Pedal Assist tab.

So, to limit the speed with assistance levels I have the choice between reducing either the Current % or the Limit Speed %.

From other threads in this forum it seems that the Limit Speed parameter changes the cadence/motor RPM, not the actual top speed. Changing it will result in different top speeds depening on what gear ratio I select on the bike.
I'd be fine with that, as i could adjust it so that the motor RPM would match a certain speed when I'm in the highest gear.
The problem I have is that when I do that, the motor also seems to reduce power output when I go up hill, despite pedalling with the same cadence as on the flat. I'm not sure why, as the Limit Current is set to 100%?
Also, on the flat I'm never entirely sure at what speed the motor actually cuts out while pedalling, so I can't really determine the "top speed" I get from a certain Limit Speed % setting.
Is there an easy way to tell when the motor cuts out, while pedalling?

The other option is to leave the Limit Speed parameter at 100%, but reduce Current to a point, where there's just enough power on the flat to reach the desired top speed.
I haven't tried that yet, but I'm assuming doing so will also mean that power up hill will not be sufficient to maintain the same speed as on flat ground?

Any thoughts?

 

[amberwolf]

The problem I have is that when I do that, the motor also seems to reduce power outage when I go up hill, despite pedalling with the same cadence as on the flat. I'm not sure why, as the Limit Current is set to 100%?

well, power is torque (~current) x rpm, so if you reduce the rpm you also reduce power. if the motor rpm is being reduced (even though you're pedalling with the same speed) then the speed % setting isn't actually doing exactly what it is purported to (though i don't know what it does actually do).

if the motor rpm is not being reduced, then the current must be.

note that any kind of limiting that engages while the motor is under sufficient load will reduce the ability of the motor to overcome that load.

Is there an easy way to tell when the motor cuts out, while pedalling?

can you feel it's vibrations? or hear it? if not, you'd have to monitor power usage. if the display shows watts, then when those drop the motor does less work, if it shows no watts then it's doing no work.

if it doesn't have that kind of info built in, then you can do it externally, like with a wattmeter between the battery and controller, or a clamp-on ammeter over the battery-to-controller wires, placing the unit where you can see the display.

when current drops, the motor is doing less work; when it stops (or drops nearly to nothing) the motor isnt' doing any work (even if it's spinning).

I haven't tried that yet, but I'm assuming doing so will also mean that power up hill will not be sufficient to maintain the same speed as on flat ground?

that is how it should work, yes. how it actually works will depend on how the software writers actually designed it. there are many ways they could have written algorithms for it to handle limiting, and some fo them are very simple, and some quite complex that also include other factors and/or other setup parameters. (the cycle analyst by grin tech is like this--most of the limiting it does depends on quite a few things, so changing any setting can affect more than you think it does).

 

[Henkkas]

Can anyone tell me where I can buy a programming cable for Bafang max drive / m400. I am told it is a different cable then the one used for BBS series.

 

[amberwolf]

Did you check out the first post of this thread?

 

[tatawaki]

Hoping someone can point me in the right direction regarding Throttle setup or what's going on.
I've installed 2.5ohm shunt resistors and running 52v @ 50amps. The throttle seems like it has two power curves. If I hit full throttle, it accelerates hard then tapers off until a few seconds later (about 30km/h) then accelerates hard again and tapers off again.
I just want full linear throttle please.
I don't notice the difference between current or speed mode. both do the same thing.
Thanks in advance.

 

[fechter]

Try testing the throttle without moving the pedals. It might be that lovely Bafang PAS priority feature.

 

[tatawaki]

It happens without pedalling.

 

[fechter]

That's a pretty strange symptom. Is it possible it's just hitting a speed limit in software and killing the power? I've had bikes where there is a speed limit but if you accelerate hard, it overshoots the limit and kills the power completely, then goes full throttle again in sort of an oscillation. If you slowly accelerate does this still happen?