BBS02 stopped working,

[Rob McGregor]

Hi everyone, a pleasure to join this group! Maybe you guys can help with an issue I'm having. Thanks in advance!

I installed a BBS02 on a mountain bike a couple days ago and was thrilled with the results. Everything was working correctly. Then, the throttle stopped working and the pedal assist stopped working at the same time. It's a 48V battery, the controller is set for 48V, the display (750C) is displaying 51V (as does the advanced charger), the brake (only one hooked up) seems to be working fine since the display shows when it is depressed, no gear shift sensor is installed, the connection to the battery seems to be fine. Everything looks to be fine, visually and on the display. However, no power goes to the chainring, and the display no longer will show power going to the bike, as is obvious from riding it. It does have one thing that might be a clue. Sometimes when the throttle is turned, the chainring turns about a quarter of an inch at its circumference before stopping. Barely noticeable, but it does happen.

I was ridding it fairly lightly when it happened. No more than 500 watts for short intervals on level ground. The motor was slightly warm, but it didn't seem unusual.
Anybody have a clue what the problem may be?

Thanks so much!
Rob McGregor

[artdrectr]

Speed sensor installed correctly? ...magnet misaligned?

[calfee20]

Disconnect the brake anyway to make sure.

[calfee20]

Not much help so far. There was a member that had the magnetic disc fail. This disc controls the PAS and I don't think it should affect the throttle. I tried to find the thread to read the symptoms but search words like PAS disc and magnetic will give 30+ pages of results.

This is reaching here because it was working, but unplug, inspect, and reconnect all of your connectors.

[ykick]

check some of the sticky threads here: https://electricbike.com/forum/forum...and-kits/bbshd

What size/teeth chain ring did you use?

Oh, what voltage system? 51V isn't really very well charged for 52V and it's only about 1/2 SOC for 48V. Probably not related since the system powers ON but just FYI...

[Rob McGregor]

Thanks for the advice! It's a 48V pack. At 51V, I think that's about 77% capacity. I'm quite certain the battery is working and connected correctly. I connected the charger to the motor to bypass any issue with the battery. Acts the same, display works, shows correct voltage, shows correct speed when wheel turns. Speed sensor led lights up and turns off momentarily when the magnet passes by it, and it shows correct speed on the display when pedaling. It's the standard 48 tooth chainring. I disconnected the brake, no change. I disconnected the speed sensor, still doesn't work. One symptom that might be a clue is the advanced charger shows a load for a split second when the throttle is turned (load indicator led on charger changes color for a split second). That corresponds to the earlier symptom of the chainring turning ever so slightly when the throttle is turned with the battery connected. Seems to turn slightly, then stop like the motor is being braked magnetically. I suspect controller, hall sensors, motor, or internal connections. Any ideas? Thanks so much! I really appreciate having this community to bounce ideas off of. Man, this thing was so fun while I had it working. Cheers!

[tommie]

When you`ve discounted everything on the outside pull the controller out and inspect all connections in there especially that white block connector. The HD is a great motor unfortunately let down by some assembly quality control issues at the factory.

[max_volt]

Do you hear a faint click when you engage the throttle? Did it get wet recently?

[Rob McGregor]

Yes, there's a faint click when the throttle is engaged, and the chainring moves ever so slightly, then stops like it freezes. Yes, the display works. No, it did not get wet. I've been researching this and it seems that it might be blown mosfets in the controller, based on others who have this same symptom. Does this sound right to you guys? Thanks!

[ykick]

Is there a great deal of resistance when rolling the bike backwards? Power ON/OFF doesn't matter. Normally there's some slight "cogging" resistance felt but if blown MOSFETs there's usually enough resistance the tire might slip on gravel or loose surfaces when rolled backwards.

48T tugging 14-12T or smaller rear cog would be too tall of gearing for BBS02, IMO. This results in too low of electric motor RPM (inefficiency) which generates excess heat inside the unit and can damage controller. There's a reason 30T front chain rings are offered for BBS02.

[Rider]

ykick - As mentioned below, my BBS02B just did this same thing. There is substantial cogging when rolled backwards without power, but I don't know if it is more than normal. What are MOSFETs? I hear that term a lot, but have never researched it. Have a good link to review on how to check them? Thx.

[max_volt]

You might want to take it apart and check all the connections and look for burnt stuff before ordering a new controller. I use and abuse my HD and it keeps coming back for more.

[Rob McGregor]

You mentioned a faint click. What does that mean in your experience? Thanks!

[max_volt]

Can't remember for sure but I think I saw a video where the guy heard a click and another one where there were sizzling noises.

[Rodney64]

Have you opened the controller. That would be my first recommendation. Check all the bullets are fully attached.

[Rob McGregor]

Thanks for all the input! I checked all the phase wire bullets. They all looked good, but I reattached them with contact cleaner. I also did that with the hall sensor connector. I tested the negative to phase wire resistance. I measured: black to yellow 1.75k ohms, black to blue 1.75k ohms, black to green 120 ohms. Maybe some blown fets? Anyway, Luna kindly exchanged it for a new motor. Works great! Thanks Luna and everyone! Cheers

[Rider]

Just had this same thing happen to my BBS02B. Haven't looked inside yet. Hope there isn't a batch of bad motors out there. Did Luna diagnose it after you returned it and let you know what it was? I started another thread for my similar problem entitled: "BBS02-B Power Assist Stopped Working."

https://electricbike.com/forum/forum/main-forum/trouble-shooting/51314-bbs02-b-power-assist-stopped-working