Bafang BBS02 Dangerous Wet Weather Short?

[Chapooski]

My wife has been commuting to work on a recumbent tadpole trike with a Bafang BBS02, DPC-18 and thumb throttle for 4 or 5 years now and over the past 6 months she has twice had an issue where power to the motor seems to continue after the pedals are stopped, the thumb throttle is not being touched and once when the brake cut-off lever was being pulled.
This of course has caused a couple of dangerous situations when the electric drive continues on when she is trying to stop or exit the trike, the most recent of which had the trike running her over as she tried to exit and the motor seemingly engaged drive on its own.
The common condition between the two events seems to have been the weather conditions as there was some light rain during both commutes.
I am wondering if there is some known wet weather shorting that can occur in the system that allows the motor to run even when the pedals are not turning, the thumb throttle is not engaged and the brake lever cut-off is being used?
I have told my wife that to be safe she should now turn off the system at the DPC-18 on/off button before attempting to exit the trike.

 

[AHicks]

Water collecting in throttle?

 

[Chapooski]

Water collecting in throttle?

Maybe? Although she rarely if ever uses the thumb throttle and definetly prefers pedal assist.
I guess I could try opening up the thumb throttle to see if any moisture is collecting inside and/or remove the thumb throttle altogether to make for one less component to suspect.

 

[m@Robertson]

The direct answer to your question is no. These motors tend to work fine in wet weather - provided you do some basics like use dielectric grease on the connections to waterproof them. Maybe some silicone sealant at the cable ingress points on the display. Plastic sheet over the throttle secured by a couple of rubber bands to prevent water ingress.

Failure conditions from stuff getting wet (its the peripherals like throttle or display getting water inside of them) is out and out failure to operate, where to get the motor going again you end up tossing the display or throttle in the old standby - a bag of rice - to draw out the moisture. I have never personally heard of a failure due to water that causes the motor to engage. Maybe @tomjasz has since he's worked in the industry supporting these motors. I certainly wouldn't discount the possibility, and its never a bad idea to shut off any vehicle when you climb off of or out of it.

and... there's this old saw: correlation does not necessarily mean causation. I would be much more suspect of a bad wiring harness shorting somewhere due to rubbing over time.

 

[tomjasz]

The entry point for the wiring has a rubber gasket. It’s not at all effective. I always suggested our customers buy a silicone based product and make a better seal. RTV is very flexible and goes a great job.IMO dialectic grease is old school . ACF50, Boeshield, and other products crested to protect avionics are a modern and better choice. Sadly BAFANG PCBs are of questionable quality. Either good or bad. The bad are low quantities but it does happen. Ive been riding BBSxx motors since 2014 and doing customer support from 12/2015 through 01/01/2022

M@ has good advice. I bought a 500w BBS01B and treated all command the internals with ACF50. IreI ride year-round in nasty Minnesota weather and have no moisture issues following my own advice.

 

[Chapooski]

Thank you m@Robertson and tomjasz for your thoughtful replies and good advice, it's much appreciated.