E-bike fell off carrier, won't power up.

[Govind]

Hi- was transporting two RadCity step throughs on a rear carrier. Sadly one fell off the bike rack during transport. Miraculously, the front wheel of the bike that wedged in the pedal of the other bike and so it did not completely fall off, but the rear wheel was dragged across the highway for about a minute at 40 mph. Pulled over and rode the bike manually, as the batteries were not on it and it seemed fine. However, it will not power up. Called Radcity, but this is not clearly a warranty issue as it was accidental. They suggested I check all connections and everything seems fine. I asked if the motor could have burned up, they said unlikely. I then asked if the regen capability could have sent a spike up to the controller and fried it (even if it was unpowered), they said unlikely.

I checked resistances across 3 pins of hub motors and they all show 0.8 ohms; not sure what is normal so will check on working bike. Question- for troubleshooting, should I connect one component at a time from the working bike to see if I can restore power? Or should I just get a new controller? I would hate to end up blowing up the working bike!

First post here and hoping someone has an answer.

Any recommendations for a e-bike shop or local helpful person that can help in the Baltimore area would be great also.

Thank you!

 

[rich c]

Does it have motor inhibitors on the brakes at the handlebars? Make sure that’s not tweaked

 

[Govind]

Hmmm- where woudl I look? I know that when the brakes are applied the motor goes into regenerative mode. But why would that prevent power up?

 

[NemoChitty]

"I checked resistances across 3 pins of hub motors and they all show 0.8 ohms; not sure what is normal so will check on working bike. "

Govind, based on that statement, I'm going to assume you are meter savvy.
Check the following switches and connections.
Great that you have a sister bike for reference.

Also everything OK on the display?

• Battery fully seated?
• Key in the "ON" Position?
• Display Powered On?

From the 2018 RadCity Step Thru, Owners Manual, On-Line.

https://cdn.shopify.com/s/files/1/0799/9645/files/2018RadCityOwnersManualUSA_11-26-17.pdf?3884245348935249554

PAGE 5
The front and rear brake levers contain safety power cutoff switches which disable the hub motors assistance when applied, both levers should be checked for correct operation.
NOT
"I know that when the brakes are applied the motor goes into regenerative mode. But why would that prevent power up?"

PAGE 17
Throttle Disable Button.



PAGE 28.
Basic Schematic.



I hope that's enough to get you to the source of your trouble.
Any questions, ask!

Respectfully, tim

 

[Govind]

Thanks so much- what a great forum!
The display won't turn on, so no way of knowing. Radcity tech suggests I connect display to good bike to help troubleshoot, which I will try that.
Wondering why the brake switch would have failed and if that would prevent a power up?

 

[harryS]

When you said not powering up, you mean that the display stays off.

Motor damage, or even a broken motor cable there should not inhibit the display from coming on, but maybe the big pull on the front wheel caused the cable between the display and the controller to separate, or maybe the cable between the start button and display was damaged. The displays on most ebikes will turn on as long as you get battery power and ground to them.

The other place to check is to trace battery power to the controller pins.

 

[Govind]

Correct, display stays off. All connectors check out OK THis is a 2019 model, so I had to check the light (head and tail) cables also, which are now controlled by the controller.

My suspicion is still on the fact that if the wheel was turning very fast as the bike was dragged on the highway, it would have generated a lot of power which had to go somewhere. And since there is a regenerative circuit, even if unpowered, I wonder if enough current got back into the control module to zap it?

There was a rubber burning smell, but the tech thinks that was just the tires.

 

[NemoChitty]

Govind, how are you making out?

Any progress?

 

[AguassissiM]

@Govind

I'm sure this will sound very silly however the sudden jolt of the bike falling off/wedging itself by the front wheel may have caused unexpected problems as poor or loose connections.
Follow the cable from the display to the connector, look closely at it, if visually seems to be ok disconnect it anyway, inspect all the pins for any damage and reconnect it making sure you have a good connection.
Personally I would do this to all connections, had one like this happened to me after a nasty spill and it turned out to be the connection from the controller to the motor got loose just enough to drive me nuts for an hour. Unplug and replug did the trick.
Good luck to you.

 

[Govind]

Fixed!!! Becuase I had two bikes, tech support suggested I line them up and plug in display from working bike into non-working one and that did it! Jolt must have killed the display.
Rode in to work today for the first time and I look like the joker with a grin plastered over my face...
Thanks for all the helpful suggestions.
Only problem is I am now too traumatized to use my carrier and that crossbar- that was the failure point. I also wonder if regular carriers that were designed to carry 4 30 lb bikes can handle the 65 lb ebikes.
The torque on the carry arm will be much greater and I wonder if the quick-release pin that folds the carry arm (or the pin used to fold the main arm will give way.
Never want to drop a bike on the hwy again....I got really, really lucky.
Any pointers or is there already a thread on this?

 

[harryS]

You used a hanging rack with one of those universal crossbars that go between the handlebars and seatfor lady's bikes?

 

[Govind]

Yes, correct.