Power cutoff for a few seconds???

[pagheca]

Hello everyone,

A hour ago I was doing a very uphill and crumbling track about 500 m long. I set the Turbo on my Trek (powered by Bosch CX Performance) and was using the highest gear, no problems.

At one point I rode up some kind of sharp step between rocks. I clearly felt the rim of the rear wheel touch the edge and at the same instant the drive torque drops dramatically, probably to zero. I pedaled hard not to stop as I was thinking about what to do, but after about five seconds, just as it had gone, the motor torque came back.

No further issues until I went home.

I have read that something similar happened to many people. Do you know why? I don't think it is a defect. I was wondering if there is a sensor that cuts the power when certain conditions occur. I think something similar happened to me time ago but I didn't really noticed because I was going faster.

Any idea?

 

[pagheca]

Has it ever happened to anyone else here?

 

[RustyIron]

Perhaps you hit an over current limit... or over torque... over temp?

In the six months I've been riding Bosch, there have been about three times when I experienced an "anomaly." It's always been when I've been riding as hard as possible on some heinous feature. As you experienced, it's hard to break it down and analyze when it's happening. And it's too infrequent to establish a pattern. I can't even say with certainty that the phenomenon was real or user induced. In my case, I don't think there's anything to get excited about at this time.

 

[pagheca]

Thanks. You confirmed my suspect. It was probably an overcurrent/overtorque. What surprised me is that I couldn't find a reference to a behaviour like this: a few sec shut down and then back again.

 

[Stihldog]

Has it ever happened to anyone else here?

Yes, and to my neighbour.
During climbs, when we are using power of course, the vibration frequency causes the power between the battery and the socket to become intermittent. In our case, and another Rail, it was poor battery alignment.

The battery would slightly rattle …and eventually get worse over time. Secure the battery. eliminate any rattling, add small chair-leg cushions around the battery. Any noise and rattling coming from this area will cause excessive wear to the electrical contact points.

IMO, if you need to use dielectric grease in this area …you’ll have other or more problems. I don’t use dielectric grease here.

 

[pagheca]

I know, I read about this here: Bosch CX Gen 4 shutting down while fast ride

 

[Stihldog]

Yeah, haven’t had a problem since I secured and fitted the battery.

Slightly moving the lower bulk-head (electrical socket) seems to have helped.

Just loosen (only) the two security Torx bolts for the lower bulkhead. Adjust for a slightly tighter fit when the battery is in place.

You may need to remove the skid plate to accomplish this.

 

[Niklas]

It happens then and then especially when riding harder in real technical terrain, it’s really annoying Love the Bosch motor except for that though

 

[Lantz]

I have the same problem on my Wild and have had it on two Trek rails and a Canyon Strive. It's very annoying when that happens. and since I got a new engine on my WIld after 130km, it has gotten even worse. Haven't had it happen on either Specialized or Shimano bikes.

 

[Stihldog]

On the Bosch motor/battery system the main power connection doesn’t seem very good, or the fine battery alignment procedure is temperamental. The female wiring connection doesn’t seem to make a very good connection to the battery.

On my Trek Rail, and two others, we had the intermittent power cutoff during trail riding. Sometimes it was unexpected but it was annoying and caused a number of power loss or computer issues.

The solution to all of these were to reposition the lower battery bulkhead slightly. Sometimes the battery alignment procedure had to be redone. The fit had to be tight. Any movement at the female connector/male battery connector would eventually become worse after each ride.

A LBS may not notice this problem. It only appears during real-world use.

 

[pagheca]

On the Bosch motor/battery system the main power connection doesn’t seem very good, or the fine battery alignment procedure is temperamental. The female wiring connection doesn’t seem to make a very good connection to the battery.

On my Trek Rail, and two others, we had the intermittent power cutoff during trail riding. Sometimes it was unexpected but it was annoying and caused a number of power loss or computer issues.

The solution to all of these were to reposition the lower battery bulkhead slightly. Sometimes the battery alignment procedure had to be redone. The fit had to be tight. Any movement at the female connector/male battery connector would eventually become worse after each ride.

A LBS may not notice this problem. It only appears during real-world use.

It happened to me a couple more times. In all cases, the terrain was very uneven, I was on a fast climb after a descent, and the connection resumed soon after, so I'm reasonably certain that it is, as you say, a connector not working perfectly.

I will try to verify what you say but, what does LBS mean?

 

[Stihldog]

It happened to me a couple more times. In all cases, the terrain was very uneven, I was on a fast climb after a descent, and the connection resumed soon after, so I'm reasonably certain that it is, as you say, a problem of a connector not working perfectly.

I will try to verify what you say but, what does LBS mean?

LBS = Local Bike Shop. It’s difficult to keep up with all these acronyms.

When my bike started failing (power/computer) it was always at a specific spot on an access road and likely a specific vibration frequency. I thought a flux-capacitor was buried under the road …it wasn’t .

Improving that connection definitely helped. I suppose with constant movement in that area the problem would become worse. …and it did.

I don’t time travel anymore so I didn’t need the flux-capacitor.