PAS level 1 on 1000w direct drive motor too fast ?

eHomer

Esteemed Pedelecer
Aug 20, 2012
635
164
I've been tinkering with my spares box, trying out a few combinations of motors and controllers and I've come across what seems like a strange anomaly, (to me anyway).

I've hooked up an old (but hardly used) 1000w direct drive rear hub motor to a BMS S12S sine wave controller and a 48v 10ah bottle battery.

I'd previously only used that motor with a much simpler throttle only square wave controller, and I was hoping to at last enable peddle assist, so that I could pootle along at 15mph, to maximise range.

The various levels of assist don't seem to moderate the power though, even at level one the motor takes all the effort, leaving me to just turn the pedals with no effort, just to keep the PAS going.

When I've used that controller with 350w geared motors, level one and two PAS enabled me to move at sub 15mph speeds and provide some of the effort.
 
Last edited:
D

Deleted member 4366

Guest
Have you set it to speed control or current control?

Parameter P3 should be set to 1 for current control.
 

eHomer

Esteemed Pedelecer
Aug 20, 2012
635
164
Aha, thanks Dave.

You've reminded me, (I think) that the S12S's LCD panel has an advanced setup menu, as well as the normal setup menu, or so I vaguely remember.

I'd tried the standard setup, but that only has max speed/wheel diam/metric-english settings.

I kept a printout of the standard settings PDF file, but can't find the advanced one, do you know where it is online please ?

Unless I've managed to confuse myself again, and I'm thinking about another controller altogether ?
 

eHomer

Esteemed Pedelecer
Aug 20, 2012
635
164
Ok, I've now just back from a 12 mile test ride after changing the P3 parameter to 1, as Dave suggested, (thanks for that).
It works fine now, with nicely adjustable PAS with the 1000w direct motor.

I can pootle along at 15mph with assist level 1, with the motor giving about half the effort.

It's a shame that the direct hub motors are so heavy and have the drag problem when freewheeling with the power off.

Their almost complete silence and good acceleration on the flat make for an otherwise very enjoyable ride in non hilly areas.

One thing that did surprise me with my S12S controller on the 1000w direct hub is the brief but quite appreciable braking effect whenever you stop pedaling and the PAS drops out. I can understand why the motor will drag on the overrun, but the sudden "blip" of braking effort is definitely greater than the subsequent unpowered freewheeling drag.