Hi All New Member...Need help with my ebike badly

[Gizmo2908]

Hi everybody I’m new to the forum, after searching through google I am really struggling to find any answers or explanation to my problem.

My problem is that I purchased a used ebike from a friend a few weeks ago all was working fine till the other day, I was out riding and all of a sudden my ebike had no power, front hub went stiff and had to push it home.
Once I got home I turned the bike upside down applied some throttle and the hub motor just clicked like it was stuck I tried it again and controller started smoking so I disconnected battery straight away and left the bike for a few days. Once I got round to finding the problem I really didn’t know were to start. After reading some info on google I disconnected the controller from my wheel phase wires and hall wires and wheel was turning smoothly so I thought ok everything is fixed and carried on connecting everything back together but on connection of battery it went bang and bits of molten metal were falling I looked at the battery connectors and they have disintegrated, I have now took all the wires apart again so I don’t wake up in middle of the night to a fire.

I need help plz as I use my bike to get to and from work,
If I have not supplied enough info then plz ask me I will try my best to answer everything

Oh I forgot to mention when the bike 1st stopped working and I tried reconnecting everything when I got bk home the fuse basically had melted and wires that come out of the controller had the outer plastic coating had melted the worst wires are the phase wires.

 

[Gizmo2908]

I am also not good at testing electrical problems like using a multimeter but I will try my hardest to learn

 

[E-HP]

Once I got home I turned the bike upside down applied some throttle and the hub motor just clicked like it was stuck I tried it again and controller started smoking so I disconnected battery straight away and left the bike for a few days. Once I got round to finding the problem I really didn’t know were to start. After reading some info on google I disconnected the controller from my wheel phase wires and hall wires and wheel was turning smoothly so I thought ok everything is fixed and carried on connecting everything back together but on connection of battery it went bang and bits of molten metal were falling I looked at the battery connectors and they have disintegrated, I have now took all the wires apart again so I don’t wake up in middle of the night to a fire.

Smoke from the controller is a sign that everything is not OK. Based on your description, you haven't acquired the skill necessary to open it up, troubleshoot, and solder in new parts. The fact that it fried the battery connector appears to indicate that the controller has an internal short. Reconnecting everything was not a good idea. Given that, at minimum you'd need a new controller.

For your battery, you will need to replace the connectors, and hopefully the battery BMS tripped to keep from damaging the battery itself. If you have a multimeter, you could check the battery voltage, and if it's normal, you may only need the connector replacement.

Was the motor under a lot of load when it stopped working (climbing a steep hill, etc.)?

 

[amberwolf]

I was out riding and all of a sudden my ebike had no power, front hub went stiff and had to push it home.

This means that the phases were shorted together. Could be all of them, or just two. This can be inside the motor, or inside the motor phase cable and/or controller phase cable, where insulation melts and lets the wires short togehter, or FETs inside the controller blown and shorted.

Typically the last one is not recoverable, so it doesn't ever start working again, but the other two can sometimes "recover" slightly when cooled down, and then when heated up again even slightly cna reconnect the short, and cause the problem (or worse ones) again, which if the short goes on enough will then blow the controller FETs requiring replacement of the controller.

Given the battery connector failure, the FETs are probably shorted, which puts a direct short across the battery wires. This means the controller almost certainly needs to be replaced, as a start.

If you want to test the controller first, there is some good documentation here
https://ebikes.ca/learn/troubleshooting.html
that may help. If you have troulbe with that, state specifically what you have and haven't done yet, and we can figure out how to show you what to test.

Oh I forgot to mention when the bike 1st stopped working and I tried reconnecting everything when I got bk home the fuse basically had melted and wires that come out of the controller had the outer plastic coating had melted the worst wires are the phase wires.

This means that the conductors in the wires got so hot that they melted things. That is very hot. Typically this means the system is not being used as designed, such as riding slowly up steep hills, or lots of stop/start traffic, or riding really hard on a system not intended for it, etc.

Other causes include a controller that is more powerful than the motor should be used with, and the motor being used in a way it wasnt' designed for, so it pulls more current than it can handle from a controller sized too big for it. This is also usually really hard on the battery, which in such cases is often undersized and run harder than it was designed for.

Another cause is a miswired motor/controller phase/hall combination, which "works" but creates excessive heat in the controller, wires, and motor. If it is used under significant load, or for any length of time, the likelihood increases of destroying the motor, wiring, and controller from overheating.

A further cause is motor wire damage at the axle exit, very common when bikes are crashed or skidded or leaned on the ground or fall over, etc. Not always externally visible, it can leave shorts between phases or even phases and halls.


Regardless of teh cause, the primary fix is either to replace the wiring completely, or to replace all of the parts that have those wires on them. The secondary fix is to look at the usage of the bike vs the parts that are on it and what they are really capable of, and either use it within the limits of the parts, or replace them with parts that can survive the usage scenario.



What I would do at this point is detail the exact usage of the bike prior to and including the failure point.

Then I would open up the motor casing to make sure the windings are not overheated and damaged. If they are, replacing the controller is likely to just blow up the new controller as soon as it is turned on, or when the throttle is turned or the bike is ridden the first time.

If the windings are ok, I would carefully examine the entire motor wire bundle for any damage, either overheating or impact, abrasion, etc. This includes opening up the entire wire bundle casing to see the wires inside it, which may require pulling part of the wire back inside the motor to see what was in the axle (where it is often damaged from heat but cant' be seen). Reinsulating this so that it is protected may require sliding heatshrink over the slit jacket, and getting that back into the axle may be difficult, so not everyone checks this section of wiring, and just hopes that it is ok.

If all of the motor windings and wiring is ok, then a new controller can be installed, along with new battery connectors.


The battery itself would need to be tested as well, because the big spark from the shorted controller can (but doesn't always) damage the BMS FETs so taht they either are open (no output) or stuck on (no protection against overdischarge). If you need help testing it we can work out instructions for that.

 

[fatty]

...controller started smoking...
I.. carried on connecting everything back together but on connection of battery it went bang and bits of molten metal were falling I looked at the battery connectors and they have disintegrated...

I am also not good at testing electrical problems like using a multimeter but I will try my hardest to learn

Repairing a high-energy/power lithium electrical system is not an appropriate project to learn on -- exponentially so without a properly-functioning BMS.

Ride a regular bike to work and leave this to a qualified mechanic.
Learn to test electrical problems on low-voltage, low-current 12V systems first.

 

[Gizmo2908]

Hi thanks for all your reply’s, this seems like a lot to do for someone like me but we’re I am located there is know one or a company that repairs ebikes so I’m am sort of stuck basically and have to try myself. I have a multimeter being delivered 1st thing tomorrow so once I have this I can start from there. Just one quick question once the phase and hall wires were disconnected from the from the controller the wheel did start to spin smoothly again.

 

[Gizmo2908]

And to be truthfully honest with you all I have put quite a bit of weight on as well since the covid lockdown happened so am I right to say that being heavier could have had an impact on the bike

 

[amberwolf]

Just one quick question once the phase and hall wires were disconnected from the from the controller the wheel did start to spin smoothly again.

That indicates the FETs of the controller are probably blown; they usually fail shorted and that causes what you see.

It could just be the wiring itself, but it's much more likely to be the FETs.

If it is the FETs, then they could've failed from too high a load, but they could also have failed from intermittent shorts inside the motor or motor wiring, which is why I brought up some of the checks you can do for that. (a simple measurement isn't sufficient to be sure; visual inspection is usually needed). If it is not possible to do those checks (which are a lot of work) then you *can* just try a new controller, but there is a risk of blowing the new one if there is indeed damage in the motor or it's wiring.

 

[LewTwo]

And to be truthfully honest with you all I have put quite a bit of weight on as well since the covid lockdown happened so am I right to say that being heavier could have had an impact on the bike

How do I say this politely: A vehicle's performance is directly related to the amount of mass it is transporting. As the speed increases it is an exponential curve.

I used to be in the Air Force. Consider this. We towed aircraft around with 4 cylinder flat head tugs. Even the LARGE aircraft (i.e. fully loaded bombers) were towed with small block v8's. They just were not towed very fast.

 

[fatty]

I have a multimeter being delivered 1st thing tomorrow

I'm all for DIY, but I have to reiterate that this is not appropriate for a first electrical project.
Consider that a 1kWh battery = 3,600,000J = 900g of TNT. And you clearly don't have working battery protection, illustrated by "it went bang and bits of molten metal were falling I looked at the battery connectors and they have disintegrated..."
You don't have the tools and experience necessary to do this safely. You are literally playing with fire.

If you play with this anyway, do it outside with a fire extinguisher ready, wear safety glasses, leather gloves, jeans, and close-toed shoes.

 

[Gizmo2908]

From what I have read I don’t need the main ebike battery to do any fet,hall sensor or phase wire test just a sufficient 5v power source, is this correct or is what I have been reading wrong

 

[TommyCat]

From what I have read I don’t need the main ebike battery to do any fet,hall sensor or phase wire test just a sufficient 5v power source, is this correct or is what I have been reading wrong

Main battery is not needed for initial testing for sure. See this thread for details and links on testing all three of the items you mention...

Testing BLDC motor's Phase Wiring - Hall Sensors and Wiring.

Should verify that your controller is indeed toast. And give you some idea of your motor's health, before controller replacement.


Regards,
T.C.

 

[Gizmo2908]

Ok thanks TC will read through it in detail

 

[rick_p]

I feel your pain, it really sucks when something you need for transportation breaks down. As somewhat of an amateur myself, the only advice I can give is to take your time, do as much research as possible before you start any repairs, don’t cut corners or be lazy, ask questions here when you are unsure (the folks on this forum know their stuff), post pictures and provide information about the results of the testing you’ve done so far. Good luck

 

[Gizmo2908]

Hi this is the controller I have for my ebike that is blown it was the mosfets all negative yellow

 

[Gizmo2908]

Would it be ok to replace it with this controller

 

[E-HP]

Would it be ok to replace it with this controller

I'm not sure you can get meaningful advice just posting pictures. Can you post links that contain the specs and functions?

 

[Gizmo2908]

Specs for 2nd picture
Model- KT48SVPRK-SJT02L
Voltage- 48v, 52v
18 MOSFET's for better power control/delivery
Rated Current- 22A
Max Current- 45A
Speed Set- 1-4.2v
Brake Input- Low level
Low Voltage Protection- DC40v
Dimensions-240*82*40mm
Suitable for KT compatible displays
Aluminium/Silver in colour
Fits all standard hall sensor motors

 

[Gizmo2908]

Specs for 1st picture
Technical Data:
Model: KT36/48SVPRLD-SLS02E
Rated Voltage: 36V or 48V (Universal)
Min. Voltage: DC30V/40±0.5V
Rated current: 22A
Max. Current: 45±1A
Speed set: 1-4.2V
Brake Input: Low-Level
Size: About 255x84x43mm
Color: Silver
Weight: About 700g
18 MOSFET
Support Regenerative Function (must use our LCD Display together to active this function)

 

[AngryBob]

Start by telling us as much as you possibly can about your motor and your battery. Both might have some identifying marks on them. Pictures might be useful. I can't see them from here.

Describe the bike, especially wheel diameter. I can't see it from here.

Also need an estimate of just how stupid and clueless the previous owner was likely to be. I can't see him from here.

Next, this "extra weight" you are carrying. Describe this using actual units of measurement. It is necessary to know the load the motor is carrying, which along with step one can help determine if the motor is capable of doing what you want. I can't see you from here.

Now, when it just "suddenly stopped working". THIS IS IMPORTANT. Speed, air temp, winds, hills or grades climbed, trailers being towed, length of ride in both distance and time, average speed, number and duration of acceleration events, ANY *repeat* ANY indications of malfunction previous to failure, THINK, take your time, if a squirrel farted within 10 feet of the bike at any time, I want to know what color. The fart, AND the squirrel. You have supplied ABSOLUTELY NOTHING useful in this area.

Clearly you have a dead short. Determining where that short first occurred, you may have more than one, can help define what parts you need to replace, which in combination with the above requested info, can also point to certain changes and/or upgrades you may need in order to prevent the same problem from happening again.

For instance, if you weigh 300 pounds and were climbing a steep hill at 5 mph for several hundred yards while using a 300 watt motor and not pedaling at all, with an 8 amp-hour battery, replacing with like parts will just be a total waste of time, money, and effort.

 

[E-HP]

I read through your thread again and don't see the information about your current system necessary to provide accurate advice, without making assumptions that may or may not be correct. In order to answer your controller question, knowing about your current bike/system and features is required. That includes not only the fundamental information, like what voltage battery you have, but things like whether or not you pedal or have a pedal assist sensor, etc. For now, I'm leaning toward the advice you received from fatty and rick_p above.

You should at least read through the forum stickies, dated or not, to help you supply complete information to obtain advice. Example:
https://endless-sphere.com/forums/viewtopic.php?f=3&t=66302&start=25#p1485445

Nobody wants to provide the wrong advice, due to lack of information, that leads to a bad outcome, like burning down your house. The combination of lack of knowledge, and impatience/moving too quickly, is a good formula for that. You are not at the point for ordering parts.

 

[spinningmagnets]

Batteries are pretty easy to figure out. Buy the battery and charger from the same vendor.

Mixing and matching the other parts is a never ending headache. Every dollar you "save" by going cheap and ala Carte is wasted as soon as it fries a week later.

Buy the motor, controller, and throttle from the same vendor.

If you can afford it right away, order a second throttle at the same time (so they are identical), and also shop for a digital multi meter / DMM. If you have no preference, sparkfun has a good starter unit for $15.

It can do 20 things, but the first year you only need it to measure 5V for the throttle and halls, and also the voltage if your battery, and I recommend 48V, rather than 36V

 

[Gizmo2908]

Thanks for the replies I have read through T.C’s link that he provided I have also watched numerous videos on YouTube about how to test ebike phase,hall sensors and controller mosfets. It is my controller that is the culprit this is the reason I asked if the new controller I found online would work.

 

[fatty]

Hi this is the controller I have for my ebike that is blown it was the mosfets all negative yellow

Post pictures of the blown MOSFETs

 

[Gizmo2908]

Will do asap