BBS02 - motor spins in cold weather, doesn't deliver power.

[larkasaur]

My BBS02 motor (500W, 48V) has intermittently not been delivering power to the crank, when it gets cold. The motor revs up high, but doesn't deliver power.
It was happening some at 20F, more at 10F. Then when I shift, so the shift sensor temporarily turns the power off, the motor may engage, or it stops engaging. This happens using both the throttle and pedal assist.

The motor only has about 750 miles on it. I accidentally disconnected and reconnected the display/programming cable while the battery was plugged in a couple times, so possibly this damaged something. But it doesn't have problems in warmer weather.

So what's going on? I have been using it at a low power level, maybe increasing the power would warm up the motor more and make it work better.

I took off the drive cover and saw it looked pretty dry - does it maybe just need more grease? I greased those gears, but haven't had the chance to test it in the cold yet. I've been using Mobil 28.

 

[circuitsmith]

Re-grease the one-way (sprague) clutch in the nylon gear.

 

[larkasaur]

Re-grease the one-way (sprague) clutch in the nylon gear.

Can this be done by adding grease to the gears under the drive cover?
There's a port in the drive cover, I can inject grease through that.

 

[larkasaur]

How much do you have to disassemble the motor in order to grease the clutch? Is there a good guide somewhere? Thanks.

 

[larkasaur]

This might be a possibility too:
"The other problem, and I have heard it has happened to some owners, is the controller loses its sync and spins the motor backwards. Then the clutch will never engage. I deliberately reversed my wires once on a motor, and yes it will spin inside the hub w/o doing anything"
Somebody said that online. It was about a hub motor, but that probably doesn't make a difference.

Is there a way of telling the two possibilities apart? My motor engages some of the time when it's very cold.

 

[circuitsmith]

Best to go in, clean and lube everything. I like tri-flow synthetic.

how to disassemble bbs02 - Google Search

Amazon.com

 

[larkasaur]

I went out this morning in 13F weather, and had no problems!
It may be that just adding grease under the drive cover has done it. Not sure yet, though.

 

[Gionnirocket]

If the motor spins but the chain ring does not I'd say it has to be an issue with the clutch.
That said... "F" riding below 30°f
But glad it's working now.

 

[larkasaur]

If the motor spins but the chain ring does not I'd say it has to be an issue with the clutch.
That said... "F" riding below 30°f
But glad it's working now.

It's my way of getting around ¯\_(ツ)_/¯. I ride my bike around down to about 0F.

 

[larkasaur]

Well, I was riding along a few days later at 13F, and the motor stopped working completely. Luckily I wasn't far from home - it was very difficult to pedal. Same at home, after the bike had warmed up: no response to either the pedal assist or throttle.
I told the seller about it. They told me to disconnect everything except the motor, battery and display, and try to start the motor in the mode that's supposed to help you walk the bike along.
When I did that, the display didn't light up at all, when I tried to turn it on. And there was smoke when I put the battery in, even with the display turned off - like the motor had a short in it.
The seller said it sounded like a controller problem. They sent me a replacement motor under warranty, and the bike is working fine again.
The initial problem with the clutch slipping might have been a controller problem actually - I read online that if the controller is bad, it can lose synch with the motor and make it go backwards, so the clutch slips. That seems likely given the controller problems a few days later.