Motor cut out problem - battery or water/corrosion?

pajtaz

Pedelecer
Nov 8, 2019
58
2
Netherlands
I have experienced an intriguing problem. It has now happened twice in similar circumstances. I would like to know what you think is the problem.

This morning on my ride to work the motor was constantly cutting out. Motor power would go to 0W then it would go back then out again then back on. t was random, at all PAS levels, sometimes it would last 3-4 seconds, sometimes 1 second. It would occur at various intervals, it was not regular. During the ride I stopped a few times, turned off everything (LCD then battery), then tried again but it kept happening all the way to work. This is the second time this happened like this.

Both times this happened was after 5-6 days of not riding, battery was off the bicycle, in the house, and battery was 60-65% charged. I would come home from work, take off the battery, I would not charge it because I charged it at work and after 18 km of commute it would have plenty of juice for the next ride to work. So the only two times I did not ride for longer than the weekend was the two times I had this problem. That is what is common.

The other thing that might be common is that both times I rode the bicycle through rain on the last ride before the ride that had the problem. Keep in mind that the bicycle is stored in storage area that is on the bottom floor of apartment building. So it is dry but cold (probably between 0 and 7 deg C for the last month).

I think I narrowed down the problem to either the battery or water/moisture in connectors. It can be the battery only if sitting in house for 5-6 days can cause the battery to somehow not provide adequate voltage. I don't know scientifically why this would happen but so far both times this occurred was after I did not ride for 5-6 days, whereas riding after 2-day weekend or every day I have no problems.

It could be the water or moisture getting in the connectors, primarily battery connector, causing corrosion which then causes increased resistance/bad connection and this causes current from battery to controller to fluctuate. I have XT60 connector from battery to controller. I disconnect this connector when I need to take the battery off the bicycle. Today I checked the male side and it had some corrosion on the PWR pin (green residue around the bottom of the pin) and corrosion was inside of the connector (green residue in the corners in various places of the connector). I can't really inspect the female side because it is on the bicycle but this side faces down, while male side faces up when plugged in. I cleaned the corrosion today as much as I could with paper and paperclip and I have now ordered some cleaner spray which will clean it perfectly (Kontakt 60 with Kontakt WL and Kontakt 61 for protection after cleaning).

On the ride back, after cleaning the battery connector, I had absolutely no issues. Bike rode perfectly. Mind it that on the way to work it was pouring down the entire time and on the way back it rained for first 15 minutes. That is why I think all other parts are ok, including the motor. Maybe water is getting inside the PAS but it looks like it is well sealed and the bike rode perfectly on the way back, considering that PAS was soaking wet on the way to work and on the way back, plus last time I rode the bike was 6 days ago so it would have time to dry.

So what do you think? Could it be something with the battery or is it battery connector or other connectors and water?

I suspect it is water so when the 3 sprays arrive, I will let the connectors dry out then clean them and protect them then add even more of the self-fusing tape. Currently there is not enough to fully protect everything from the top or the bottom.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
9,241
3,536
56
West Sx RH
Moisture esp on the power + side will cause issues and may be he reason for the intermittent cut outs, the oxidisation in the connector is likely the prime suspect causing a bad contact.
 
D

Deleted member 25121

Guest
Most likely a problem with water getting into something, could be the connectors, the controller, the display, the sensor or the motor.
Self amalgamating tape around the connectors is a good place to start tracking it down, before you do that look around each of the parts to see it there are any obvious places water could get in and also look for any stains left by water ingress.
 

pajtaz

Pedelecer
Nov 8, 2019
58
2
Netherlands
Currently I don't have the problem after cleaning the battery connector. I only cleaned it with some soft tissue but once the sprays I purchased arrive, I will properly clean it and protect it.

I don't think it's a problem with any of the other connectors since the problem went away as soon as I cleaned the battery connector. However I will do what ebiker99 suggested to all other connectors. I will attempt to make it such that no other connectors can ever have water getting in. Initially when I set everything up my aim was to do this. I settled for not completely covering everything (from connector connection all the way to exit from controller box or from connection sufficiently down) because I thought there is no way for water to get in easily, even in heavy rain, especially from the bottom. Now I think I really need to use the self-fusing tape to the point that it does not allow water dripping in, splashing in or splashing from the bottom.