Bafang BBSHD Program

The desired performance of the Surly Wednesday Fat Tire bike.

I have a Touring Bicycle with a BBS02 Motor that I have set up perfectly for me.  It is set to give that feeling like I am doing the work, but a much younger me. I wanted to duplicate that feeling with the Wednesday trail bike.  

The riding speeds and power needs are different for my touring bicycle and my trail bicycle. The programming is different as well. On the Surly Wednesday, I installed a BBSHD. The BBSHD motor is more powerful than the BBS02.  The Wednesday is geared way lower for trail riding.
(42t Chainring & 34/22 10sp cassette) 

As an 'old guy' I try not to push too hard or do extreme mountain biking trails. I wanted the bike for riding on fairly easier trails that needed wider tires. Most of the time, the Surly Wednesday will be ridden on flat dirt/gravel surfaces and some easier single track trails.  For this riding, I feel comfortable riding about 12-15 mph. I wanted to achieve that feeling of

"riding like I am doing the work, but a much younger me". 

When pedaling, I want to feel resistance, and I do not want the bike to 'keep going faster' which makes my cadence have to increase uncomfortably. That higher cadence gives that 'ghost riding' effect. I want to avoid ghost riding.  To achieve this, a lot of changes were made to the factory programming of the BBSHD motor. Followed by testing, then more setting changes, and the process continued . After many setting adjustments, I found the following programming settings work great for my Surly Wednesday, trail riding style, riding surfaces and use of a small 48w 10ah battery. (I have a few of these  batteries that I rotate. I can carry an extra one or two of the batteries for longer range if needed.)

The Settings that work well,
are listed below in screen shots and explanations. 

THE BASIC SETTINGS:
Assist 1 level, is dialed down from the factory setting to,
            Current limit 10%  & Motor Speed limit of 10%  
There was just too much power & speed at the higher factory setting. On a flat terrain, the assistance kept building up speed, way above what felt normal.  At this setting, my normal cadence, makes the acceleration and speed feel good and real.  When slowing down for curves, then pedaling back to get speed, the needed power as I pedal feels normal...just me, a little younger and stronger.

Assist 2 level, As the assist levels increase, a bit more current and motor speed is allowed. 
When the terrain gets a little steeper, down shifting to a lower gears happens like in normal riding. when the pedaling become too hard, increasing the assistance level increases the allowed current and motor speed.  This enables the bike to get over the steeper terrain and the riding experience feels normal.  

Assist 3 level,  (same reasoning as level 1 ... increase level as more power is needed for terrain)
Assist 4 level,  (same reasoning as level 1 ... increase level as more power is needed for terrain)
Assist 5 level,  (same reasoning as level 1 ... increase level as more power is needed for terrain)
Assist 6 level,  (same reasoning as level 1 ... increase level as more power is needed for terrain)
Assist 7 level,  (same reasoning as level 1 ... increase level as more power is needed for terrain)
Assist 8 level,  (same reasoning as level 1 ... increase level as more power is needed for terrain)
Assist 9 level,  (highest level for emergency needed power .. but limited for equipment safety)

The PEDAL ASSIST SETTINGS:
Notes on specific settings

Speed Limit

I set the Speed limit setting in the Programming and not the Display.  The settings of the display are more cumbersome and I started to question if it was worked properly when the setting was done in the Display. I set the speed limit to 30km/h (about 19 mph).  For my riding with the fat bike and the way it is geared, that is about as fast as I want to go.   If the setting was higher, the 'Ghost Riding' happened. 

Start Slow Mode
I dialed this down to 3.  With the power of the motor and the low gearing of the bike, the start-up jerks, are minimized with this lower setting.  Less strain on the components and the power sensation seems natural for the gearing at the setting of 3.  The 3 setting give the normal for me amount of pedal power build up.

THE THROTTLE HANDLE:
The throttle is something that is not used often. I have it set to the Assist Level 9, the most powerful setting.  It is something that can be used in emergency situation when a lot of power and motor speed might be needed. The speed limit set for the throttle is still at the 30km/h or about 19mph.   The Assist Level 9 has the motor speed limit % set at 75 (about 135 rpm).  With the 42t chainring, the max speed of 19 mph should be attainable in with most of the 10 gears in the cassette (yet to be tested).

Having the ability to program the Bafang motor is a great feature.
The 'best' programming will depend on :

1. the build of the bicycle, (Battery, gearing, rim size, tire size..etc)

2. the type of riding the bike will be used for.  

3. the riding style of the rider. (cadence, power, effort, speed) 

4. physical characteristics of rider.

5. load.

My advice:
determine the goal is of the programming. Then adjust the settings and test to attempt to obtain the goal. Continue to change the settings to move closer to achieving the goals.  Just keep adjusting the settings and testing, again and again.  It takes time and patience.