Bafang BBSHD 1000W mid drive- New build a few questions - Display, watt usage and torque at rear wheel

[goingup4m]

Hi, I just finished a build putting a bafang mid drive on my Giant Trance mountain bike. I have a couple of questions:

1. I have the 500c mini color display. Seems real nice but it doesn't always show the power output (watts). Is this typical, any idea why sometimes it will display the wattage output and other times it doesnt? Seems like in certain gear vs pedal assist levels if just goes to 0. Definitely not consistent.

2. So this is a 1000W motor, if I am just running the throttle or at a high pedal assist level my wattage output is often over 1000W. Is this OK for the motor, I would guess if you ran it over this level for to long you may overheat the motor? Maybe there are safeties already built into the motor and it will shut itself down if it gets to warm. Any thoughts on this?

3. So this bike is a full suspension mountain bike with an aluminum frame. When the power kicks in there is a noticeable wiggle in the rear wheel. Feel like the torque is pulling the rear of the bike to the right. I tried a couple of different front sprockets, the one with a larger offset seemed to lessen the amount of pull. Also assist level 1 is not as bad as assist level 5. I am somewhat worried about the frame of the bike and the wear and tear over time. Wondering if anyone else feels this and if there is a fix.

 

[AHicks]

All of the displays I've seen will only register watts when the motor is pulling power. Stop pedaling for instance, at any speed, and the watt meter is going to go to -0-. Same may be true if you are "ghost pedaling", where you are pedaling, but providing little if anything in the way of power to drive the bike forward.

Your motor is RATED for 1000w. If you were to supply it 3 times it's rated power, you wouldn't see any smoke for a few minutes, and meanwhile you would be getting some pretty increible performance from your 1000w motor! If allowed to cool after that, you could repeat that 3000w performance with no damage - as long as it's allowed to cool afterward. This power rating "game" is played by quite a few bike manf's who install motors rated at 350-500 watts for instance, and rate the bike for 750w as that's the max they allow it using the controller to cap available power. So yes, OK, but just temporarily, as long as the motor is allowed to cool afterward.

As far as the wiggle, if the spokes are tight and nothing is moving around, I can't help. -Al

 

[goingup4m]

All of the displays I've seen will only register watts when the motor is pulling power. Stop pedaling for instance, at any speed, and the watt meter is going to go to -0-. Same may be true if you are "ghost pedaling", where you are pedaling, but providing little if anything in the way of power to drive the bike forward.

Your motor is RATED for 1000w. If you were to supply it 3 times it's rated power, you wouldn't see any smoke for a few minutes, and meanwhile you would be getting some pretty increible performance from your 1000w motor! If allowed to cool after that, you could repeat that 3000w performance with no damage - as long as it's allowed to cool afterward. This power rating "game" is played by quite a few bike manf's who install motors rated at 350-500 watts for instance, and rate the bike for 750w as that's the max they allow it using the controller to cap available power. So yes, OK, but just temporarily, as long as the motor is allowed to cool afterward.

As far as the wiggle, if the spokes are tight and nothing is moving around, I can't help. -Al

Thanks for the input. Very helpful

 

[MartsEbike]

3)
If I was you I'd access the settings on the Bafang controller, and maybe change the Slow-Start Mode parameter to a lower value, so the power kicks in a little lower, hopefully lessening the wiggle effect. You will probably need to buy a programming cable to do so if you don't already have one.

Slow Start Mode(1-8) – Controls how fast the power ramps up when you start pedalling 8 is fastest 1 the slowest.

 

[tomjasz]

Lectric Cycles, at the time managed by Chris Head, reported that BBSHD mid drives could easily put damaging stresses on some full-suspension bikes. If memory serves, they were using Giant full suspension MTB

 

[Terry777]

I think the HD & Ultra very similar, I have the Ultra. 1000w nominal 1500w peak is the norm for these motors. The frame twisting is also something I’ve heard of but never actually saw or know anyone who has. It is a documented thing though. You can adjust the programming a lot. There are a few sites where you can get this info. Just type Bafang HD programming into a search. I’m sure there’s even a thread on the forum. Be careful bro, the HD is a powerful motor!

 

[tomjasz]

Here's some help.

 

[Tom@WashDC]

I watched the review on EBR of the Biktrix Juggernaut Ultra FS below. At 25:17 he discusses the same flexing in the the rear end due to the high torque of the Bafang motor. Probably going to be a standard feature of your build.

 

[goingup4m]

Thanks for the input guys. I bought a cable and have been playing with the programming. A recent cold snap and snow storm is limiting the test rides though..

 

[Terry777]

Thanks for the input guys. I bought a cable and have been playing with the programming. A recent cold snap and snow storm is limiting the test rides though..

Did you remember to save your factory settings before you started playing? If not copy someone’s so if you change something by mistake or it corrupts you have settings to go back to. Have fun! It’s really programmable.

 

[goingup4m]

Yes I did, thanks for the tip

 

[tomjasz]

See page 2 of this thread for .el (programming parameters from several sources)
Please use with care!

page-2

 

[PedalUma]

Lectric Cycles, at the time managed by Chris Head, reported that BBSHD mid drives could easily put damaging stresses on some full-suspension bikes. If memory serves, they were using Giant full suspension MTB

Fatigue limit - Wikipedia​

https://en.wikipedia.org › wiki › Fatigue_limit




The fatigue limit or endurance limit, is the stress level below which an infinite number of loading cycles can be applied to a material without causing fatigue failure. Some metals such as ferrous alloys and titanium alloys have a distinct limit, whereas others such as aluminium and copper, do not and will eventually fail ...

I sold my HD as fast as I could. I did not want to break a new $2,000 frame. It was too much. A thrill for several rides but as a bike mechanic I knew what it would do to cassettes, chains and frames.

 

[tomjasz]

Dropbox

www.dropbox.com