BH Atom Street 2019 - no assist power while display is still on & seems to be fully functional


New Member
Hello everyone on EBR, i have the BH Atom Street 2019 with Brose mid motor. It's been a great bike for the past 1 year and 1800 miles without any problem until today. While the display still shows the bike is in the Eco+ mode (or any other assist mode), i have no assistance or power from the motor. If i take the battery out and put it back, it seems to work for a brief moment, then it'd lose the assist afterward in a couple of minutes. I scanned the forum for similar issues in vain. I've tried to clean the battery pins & the removable display connectors so far, but that doesn't fix the problem. I've also sent emails to BH (no US warranty) & dealership & hope they'll response. I'd appreciate if you folks can point me to any clues for this culprit. Thank you!
Whenever that happened to me, it was because the battery became unseated due to rough road. Reseating it fixed the problem. It does recur. I have been thinking about putting some kind of foam or rubber spacer in there at the top or bottom to keep it snug, but haven't decided which end to try.
Thanks for the suggestion. i checked the battery connectors and seating - all seem snug-fit and tight. Still intermittently lost assist. The local dealership does not take on repair of ebikes not sold from their shop, but they kindly recommended that i be patient and pull out all the sensors, cables, then clean and reconnect. That's what i'll attempt to do next. I think on this brose s, there are speed and torque sensors (the latter of which i need to find out where)
My bike pulled that loss of contact thing again, and I pulled over. Before I did the battery re-seat thing, a minute or two had gone by, and by then I got this error msg on my display. But I just re-seated the battery as usual and it worked as usual.
This problem (loss of motor, but not display) has been written about before. Search for any posts under my screen name.

There is a pin that is part of a cluster of five pins, all spring loaded, that are about the diameter of a pencil lead that are under the battery. Sometimes shimming that cluster (remove the two screws holding the cluster of pins and shim underneath it) works, sometimes not. Greasing the connections with electrical grease probably helps. What I have done that is helping is to wrap four or five thicknesses of teflon tape around the lock that inserts into the battery when you lock the battery to the frame. It looks just like a small lock that would be on a door in your house. There is enough play in that lock/battery junction that the battery can move ever so slightly. When that lone pin of the five loses connection briefly the bikes brain thinks the battery has no voltage and shuts down power to the motor to avoid draining the battery too low.

Remove the battery, turn the key so the lock extends, wrap with teflon tape, turn the key to retract the lock, re-insert the battery then lock the battery in place. Please let us know if it helps. Its one of the few flaws to an otherwise excellent bike.
Also, the display and the button pad with the + and - buttons and the power button can each be removed. More pins underneath each that can gather dirt which may impede the electrical signal. My power button was rather dirty underneath, but it is a mountain bike and live in the dirt. There is a little set screw on the backside of the power button module that you have to remove to get to the pins and connectors. Probably need a 2mm allen key.
It could be also the pins inside the charging port of the battery. There r 5 of them and each retracts a few mm when the bat. is inserted. Due to the cables inside the bat. in the back of those pins slightly moving over time , they may block one of the pins and then of those pins may not function properly.

To test: Carefully push on each pin with a non-metal object and they should retract/extend a few mm .
Taking the controller off and replacing doesn't fix the problem, but reseating the battery always does, at least for me. I'm going to try the teflon tape on the lock bolt thing and see if that fixes the problem permanently.
I took a velcroed elastic strap and wrapped around the battery in the middle of the battery, to see if it would help keep the battery from needing to be re-seated. Helped some, but I still had intermittent disconnection problems. So then I shifted the elastic band down to the bottom of the battery. This helped a lot! We went for a ride and so happens we ended up getting onto some really gnarly trails with serious tree roots. And the BH Atom Diamond Wave Pro is not a mountain bike! At any moment I expected the battery connection to crap out, but it just kept on powering that Brose motor and performed like a champ.

Then I wrapped some teflon tape around the locking bolt, as described above. So far, so good. 🙂