A squished Motor Cable Can Be Disastrous

[saneagle]

A friend brought his wife's bike to me today to figure out what's wrong with it. It's a Woosh Camino. The story was that the bike was taken to a bike charity shop to fix the loose centre-stand. When they tightened it up, the motor cable was trapped under it and got completely squished. The motor cable is attached directly to the controller, which is potted, which for most people would mean a replacement controller would be needed. It could be repaired at that stage by cutting it open, soldering the wires back together and insulating with heatshrink if somebody had the competence.

Unfortunately, as you'd expect, the owner tried to ride the bike in that condition, which is what caused the disaster. The 36v in the motor phase wires was shorted to one of the hall wires, so, as soon as power was attemped, the hall blew. Now, for most people, it would need a new controller and motor. If it shorted to the red 5v wire, it would also have taken out the throttle and PAS, which only leaves the LCD out of the whole electrical system. Unfortunately, the replacement controllers from Woosh have a new LCD, so yes, that had to be replaced too.

The guy had already fitted the new controller and LCD, but it still wouldn't run because of the blown hall sensor that I found. I will therefore attempt to repair the motor, like our friend nepasmecrire did a couple of months ago.

The moral of the story is never to attempt to run your ebike if the motor cable is damaged. The same applies to when the motor runs rough or doesn't turn at all because you can do severe cosequential damage to the controller.

 

[Waspy]

This is why I like to build my own eBikes from kits.

Every component can be unplugged and replaced if needed.

Running a cable directly from the motor to a (potted) controller just seems nuts to me.

Also, why did your friend not take the bike to you in the first place to fix the loose stand?

 

[saneagle]

This is why I like to build my own eBikes from kits.

Every component can be unplugged and replaced if needed.

Running a cable directly from the motor to a (potted) controller just seems nuts to me.

Also, why did your friend not take the bike to you in the first place to fix the loose stand?

The motor has a connector at its end of the cable. The rest runs all the way to the controller. that's fairly normal for bikes with controllers in the battery mount, and so is potting because the water can run down the battery, through the connector and into the controller.

I had a go at him about not calling me first. He blamed his wife for trying to get it fixed without telling him. There's a lesson there somewhere, but I'm not sure what it is.

It reminds me of one bike I had to fix years ago. A guy took his ebike to Halfords to fix a puncture. They wanted to remove the tyre to fit a new tube (higher charge), but there was no connector on the cable. The cable therefore restricted the wheel removal, so they cut it, fixed the puncture and gave it back to him like that.

Another one I had to repair that tickled me was when another guy took his ebike to Halfords to fix a puncture. During the repair, the technician spotted that the disc screws were loose. Unfortunately, he knew his stuff, and he recognised that the cheap Chinese hex screws provided with the motor were nowhere near as good as the normal loctited star type, and he reasoned that was why they'd come loose, so he replaced them with the deluxe ones (higher charge too) and made the disc nice and tight. When the guy tried to ride his bike, there was a horrible graunching noise, as the too long screws gouged their way through the stator windings.

 

[Waspy]

The motor has a connector at its end of the cable. The rest runs all the way to the controller.

Sorry, I misread that bit then, I thought you meant it was a cable between the two components without a connector.

I had a go at him about not calling me first. He blamed his wife for trying to get it fixed without telling him. There's a lesson there somewhere, but I'm not sure what it is.

Never try to find lessons (or logic) in these situations.

A guy took his ebike to Halfords to fix a puncture.

We would never dream of such a thing when we were kids. We had to fix our punctures using spoons from the kitchen drawer as tyre levers.

 

[Nealh]

That's is one reason why I'm not a fan of Lishui ( we know Tony loves them), a new display as well was needed as likely the old one wasn't compatible or needed dealer pairing up via the software.
Back to KT again , one controller and all would be ok again once the Hall issue is sorted.