Store bought ebike got stuck in full throttle, brakes wouldn't disconnect motor.

N8!

10 mW
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Jul 11, 2023
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Ponce
This one is a bit long as there's some backstory. TL;DR, cheap bikes hurt you

In mid Jan 2023 I got a new ebike, sort of... it's a kit on a crappy bike, all the bike bits are Box Store quality, the build was pretty bad too... but PAS is awesome, and cruise control is awesome and with some fenders, panniers, stem spacers, grips and Brooks saddle it's a decent enough bike. I've racked up 600 miles since Jan on it. Not a lot of miles, but riding it regularly.

In early July the twist throttle stopped working, I contacted customer support, they put me in contact with local support who said it would need to be returned to the point of purchase for warranty work.

Of course support didn't contact the local dealer so at point of purhcase they had no idea what I was talking about when I took the bike to them in August to see if the warranty work/part could be done. However, the PoP shop took over the case for me and dealt with the supplier... time goes by until finally last week they contact me to bring the bike in, the replacement part has arrived.

The evening before I drop the bike off I take a ride, 14km climbing and 14 descending, fast AF, brakes dialed in, rims true, bike rides well for what it is. I dropped it off and told them the head light occasionally didn't work and demonstrated that it needing a bit of a bounce to light up.

The local shop fished a new wire through the downtube for the headlight and replaced the headlight switch, both under warranty. The shop also replaced the controller and billed me for it, $130, apparently this part is out of under warranty. failed_controller.jpg

Ok...that sucks and is a lot of money... I pay and take my bike, the motorcycle mechanic was happy to point out the headlight work.

Today I take it for a ride, during pre-flight check I had to install the front wheel, I noted the tires are a bit soft and topped them up, brakes felt a lot stiff and the cable adjusters were spun all the way in at the brake levers.... that's odd, someone adjusted my brakes..... but in pre-flight testing the brakes worked correctly... so... battery full... off I go.... 7km up, not too fast, mostly twist throttle in cruise control.... and the brakes felt great but twice it seemed a bit slow to shut off the drive. (this is what we call foreshadowing)

I was filming my ride on descent, taking it slow, staying under 25mph in the downhills and 18mph in the up hills, I got to the top of the last hill and touched my brakes to shut off the cruise control.... but the motor kept going full tilt.... I grabbed the brakes and applied force, the motor strained against it... I had slowed enough to turn around and headed uphill.. the motor continued to run at full throttle. I pulled my cell phone off the mount so it can be seen, I'm pulling the left (rear) brake lever and the motor is still accelerating. 250w uphill is not much, but still... obvious problem is obvious

I held the power off button for 3 seconds and the motor shut off when all power was off, it was a long 3 sec.

The next issue was not due to the motor... but..... someone adjusted my brakes

with the motor powered off I headed back down the last hill in acoustic mode, and the first pull of brakes the left (rear) brake made a fun snapping sound and pulled all the way to the handlebars, naturally I tightened on the right hand side and that's about the time the right lever (front brake) make the same sound and also compressed all the way to the handlebars and the bike began to accelerate.

I bailed off the bike and managed one hop before gravity got the goods on me, the next hop I landed on my knees and toes and slid like I was on a skate ramp. Nasty gravel rash on the right knee.

I limped down the hill walking the bike, both brakes completely compressed and barely any drag to slow the bike. I noted a loose brake cable on the rear brake cable.

The BSO is back at the shop I purchased it from, I spoke with the owner of the shop and shared this video... I think warranty should have covered the previous controller, this one failed in such a manner I don't know if I'll ever trust this bike again


 
Sorry you got borked by your crappy bike. Crappy bikes and DIY bikes do fail full on sometimes. We can take measures against it, but the only sure thing is a physical battery power cutoff.

If your brakes can't drag a 15A controller to a standstill like it isn't there, you have seriously wrong brakes. Are they mega cheap discs?
 
I have to agree with Chalo on the brake strength. (doesn't help that apparently the shop did not tighten the cable pinch bolt on the caliper(s).

Sounds like whatever they did in replacing the controller, they didn't reconnect the ebrake cutoff wires, and/or the throttle ground is high resistance (which leads to the throttle signal being stuck higher than it should be, leading to motor being stuck on to some level).


The latter would make sense if a problem with the throttle was the reason they replaced the controller (which would then mean that the old controller is probably still fine; it's a wiring issue somewhere between throttle and controller).
 
Are they mega cheap discs?

I'm guessing yes, it's only the 1st cable activated disc brakes I've ridden, here's the bike in all it's "glory", if there's a list of "Do Not Buy" this thing should be top of the list.

Sounds like whatever they did in replacing the controller, they didn't reconnect the ebrake cutoff wires

the brake cut off worked a couple of times.. till it didn't

after sleeping on the issue I think I've been taken by the bike shop, I don't know if there's any consumer protections in this colony (Puerto Rico) so likely I'm just screwed.
 
That's my basic pre-ride check. Lift the wheel, twist the throttle, see it spin and then make sure motor shuts off when I apply the brakes.

I've found that a bad throttle connection can lead to a full-on acceleration, but brake cut-off switches should inhibit the motor.

To get technical, basic throttle operation uses three wires: power, ground, and signal. If the ground connection breaks, you get full throttle. This has happened to me twice on my DIY conversions, when I accidentally pulled the connector apart. A brake lever switch has two wires. If one or both fall off, the brake cutoff won't work. When your shop replaced the controller, they must have screwed up,
 
If you have a multimeter, you can check whether the cutoff switches are working at the connector before tearing things apart.
I do but the bike is not in my possession. I pulled opened the "old" controller and can't find any failed components or magic smoke damage. I did note that there's a bridge that looks suspiciously like regen on that board, it's a cheap $20 controller, they charged me $130 at the shop and I'm bleeding now. Seriously irate about this.. but it's encouraged me to get my bum in gear and build a good bike.

I've found that a bad throttle connection can lead to a full-on acceleration, but brake cut-off switches should inhibit the motor.
...... If the ground connection breaks, you get full throttle.
you and @amberwolf have both said the same thing, that's very likely to be the culprit... The wires were originally bundled in a tight group held with small black zip ties. I'll bet that the same zip tie that caused a short in the headlight affected the HAL sensor wires too. When the shop fished the headlamp wire through the HAL wires moved enough to compelete the circuit and all was well... until it wasnt'
When your shop replaced the controller, they must have screwed up,

yeah, that's an understatement. When they put the brake levers back on they screwed up that too.

I don't trust them to know what they are doing, this is my punishment for attempting to get warranty repair.. no this is what I get for not building a good bike and putting a conversion on it myself.
 
I feel sorry for you. $1500 for a pos with bad after sales service would get me going too. If nothing else bad mouth the bike shop all over PR's social media.
The dozen of us on Mastodon know about it, other SM is not my thing and running my mouth is not a going to make anything good happen. Besides, It's a small island, I married in but will forever be gringo.

The shitty thing is the price attracts the people that can't afford anything else, I'll build another bike (eventually) but someone else is going to drop their last dime and get the same treatment.
 
the brake cut off worked a couple of times.. till it didn't
If both ebrake and throttle share a common ground wire to the controller, any fault in that wire would affect both at the same time. Ebrakes wouldn't work, and throttle would jam to full on.
I did note that there's a bridge that looks suspiciously like regen on that board
I don't know what you mean by this. Regen is not a specific part on a board, it is a function of the software, for a brushless controller.
 
I don't know what you mean by this. Regen is not a specific part on a board, it is a function of the software, for a brushless controller.
often these generic boards have options that aren't implemented.

see this video for an example.
 
often these generic boards have options that aren't implemented.
They may not have wires or jumpers or pullup (or pulldown) resistors to the pads that activate or control a function, if that's what you mean by "aren't implemented". Sometimes connecting these up the same way that another board that does regen that has these same pads will enable regen (or whatever function the pads are for).

But there are numerous boards that have pads with the same markings as other boards that have regen, but that do not have regen built into the software, or it has been disabled in the software. Connecting up the pads that control it the same way that the sometimes nearly-identical board that does have regen is connected won't enable regen in those cases, even though the boards "look" the same.

There are also boards with the same markings as other boards with a function, but when connecting them up on the board being worked with they do something else, instead, as determined by the software in the MCU. (or the factory settings for that software, which is effectively the same thing since there is typically no user-available software to change those).


Either way, the point is that there are not specific identifiable parts of the board that do the regen, that is in the motor-control software on the MCU itself.

The same gate control and FETs are used on boards with and without regen; these are the parts that control the motor; regen is really just negative (reversed) current flow compared to the direction it flows for traction; it can be derived in a few ways, but all of it is done by the MCU controlling the gates to the FETs in different ways, not by separate parts on the board for units with regen vs without. ;)
 
This one is a bit long as there's some backstory. TL;DR, cheap bikes hurt you

In mid Jan 2023 I got a new ebike, sort of... it's a kit on a crappy bike, all the bike bits are Box Store quality, the build was pretty bad too... but PAS is awesome, and cruise control is awesome and with some fenders, panniers, stem spacers, grips and Brooks saddle it's a decent enough bike. I've racked up 600 miles since Jan on it. Not a lot of miles, but riding it regularly.

In early July the twist throttle stopped working, I contacted customer support, they put me in contact with local support who said it would need to be returned to the point of purchase for warranty work.

Of course support didn't contact the local dealer so at point of purhcase they had no idea what I was talking about when I took the bike to them in August to see if the warranty work/part could be done. However, the PoP shop took over the case for me and dealt with the supplier... time goes by until finally last week they contact me to bring the bike in, the replacement part has arrived.

The evening before I drop the bike off I take a ride, 14km climbing and 14 descending, fast AF, brakes dialed in, rims true, bike rides well for what it is. I dropped it off and told them the head light occasionally didn't work and demonstrated that it needing a bit of a bounce to light up.

The local shop fished a new wire through the downtube for the headlight and replaced the headlight switch, both under warranty. The shop also replaced the controller and billed me for it, $130, apparently this part is out of under warranty. View attachment 342288

Ok...that sucks and is a lot of money... I pay and take my bike, the motorcycle mechanic was happy to point out the headlight work.

Today I take it for a ride, during pre-flight check I had to install the front wheel, I noted the tires are a bit soft and topped them up, brakes felt a lot stiff and the cable adjusters were spun all the way in at the brake levers.... that's odd, someone adjusted my brakes..... but in pre-flight testing the brakes worked correctly... so... battery full... off I go.... 7km up, not too fast, mostly twist throttle in cruise control.... and the brakes felt great but twice it seemed a bit slow to shut off the drive. (this is what we call foreshadowing)

I was filming my ride on descent, taking it slow, staying under 25mph in the downhills and 18mph in the up hills, I got to the top of the last hill and touched my brakes to shut off the cruise control.... but the motor kept going full tilt.... I grabbed the brakes and applied force, the motor strained against it... I had slowed enough to turn around and headed uphill.. the motor continued to run at full throttle. I pulled my cell phone off the mount so it can be seen, I'm pulling the left (rear) brake lever and the motor is still accelerating. 250w uphill is not much, but still... obvious problem is obvious

I held the power off button for 3 seconds and the motor shut off when all power was off, it was a long 3 sec.

The next issue was not due to the motor... but..... someone adjusted my brakes

with the motor powered off I headed back down the last hill in acoustic mode, and the first pull of brakes the left (rear) brake made a fun snapping sound and pulled all the way to the handlebars, naturally I tightened on the right hand side and that's about the time the right lever (front brake) make the same sound and also compressed all the way to the handlebars and the bike began to accelerate.

I bailed off the bike and managed one hop before gravity got the goods on me, the next hop I landed on my knees and toes and slid like I was on a skate ramp. Nasty gravel rash on the right knee.

I limped down the hill walking the bike, both brakes completely compressed and barely any drag to slow the bike. I noted a loose brake cable on the rear brake cable.

The BSO is back at the shop I purchased it from, I spoke with the owner of the shop and shared this video... I think warranty should have covered the previous controller, this one failed in such a manner I don't know if I'll ever trust this bike again


Thread is a little old but if black ground wire of throttle had issue anywhere or if throttle body is cracked leading to glued resistor inside losing contact with ground, BRAKE CUTOFFS WILL NOT WORK even if connected properly if controller board is usual KT style. I've tested this extensively on almost a dozen controllers after the first bike came into me for repairs with this issue. The Sabvoton and Kelly are the only controllers I've tested that prevent this behavior so far. Haven't got my hands on vesc controller like far driver yet.
 
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Thread is a little old but if black ground wire of throttle had issue anywhere or if throttle body is cracked leading to glued resistor inside losing contact with ground, BRAKE CUTOFFS WILL NOT WORK even if connected properly if controller board is usual KT style. I've tested this extensively on almost a dozen controllers after the first bike came into me for repairs with this issue. The Sabvoton and Kelly are the only controllers I've tested that prevent this behavior so far. Haven't got my hands on vesc controller like far driver yet.

thanks for the info, the bike still sucks, the rear brake cut off doesn't work, I suspect it's the pressure switch in the brake lever.
 
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