Killed my controller or bms?

[DeadEyeDave]

Hey guys, long time lurker, first time poster.

So i messed up, let me try and explain the situation, im no electrician by any means so i hope i can explain enough for some help.

So i have a sabvoton 72150 and i just recieved my battery. I hooked it all up, everything was going great. I did the hall test and was ready to get my bike on the road and i noticed thwt i forgot to plug in the little alarm that came with the controller. There is a 2 wire plug to the alarm and i went to plug that one in (red and black wires) and one of the tabs must have been pushed to the side and when i tried to push it together i guess they touched.

There was a snap and a spark at that connector and now nothing will turn on. No led at the controller, the display will not come on and where the tabs touched in the connector there is a little bit a bit of black soot.

I unplugged the positive and negative from the controller and plugged them back in hoping it would reset or something and when i did that there was a spark after connecting the positive wire but nothing at the controller. No led, no display.

Did i just mess everything up? I really hope i havent. Between the frame and motor and battery and all of the other stuff i have literally spent thousands trying to put this thing together and the battery just came today and i was hoping to ride to work before i messed this up.

Can anyone give me some advice?

 

[eee291]

If it sparks when reconnecting the controller, then you can be sure that the BMS is fine.
Don't have experience with sabvoton, maybe it's fixable.

 

[Adrian_]

Highly unlikely that you killed the BMS, they are designed to be able to handle shorts and have short circut protection, the sabvoton on the other hand, no. From my experience the Sabvotons are super sensetive and have no protection against shorts or reverse polarity and it's very easy to kill them. I have a box of 5 or 6 sabvotons all dead from shorts like salty snow getting inside connectors and shorting them out, unplugged male JST SM plugs touching positive terminal, shorting and killing the controller and so on. In most cases it's MCUs that die, in some cases if you can order them and replace them but since you said you're no 'electrician', I'm guessing you don't have tools like a soldering iron and the knowledge to be able to track down the defective component, maybe even have to reverse engineer the controller to be able to replace it and repair it. if it's a chip with software or data on it that died, you will not be able to repair it as I doubt Sabvoton sells stuff like that.

 

[DeadEyeDave]

I do have a soldering iron, some flux and some solder and more time than money. Its upsetting to think that one little short would kill such a major part of an ebike. Is there a better brand of 72v 150amp controller out there that would work with the display and throttle and everything i bought with the sabvoton? I'm guessing no. I am regeetting the money ive already spent on thos project.

Tomorrow when i wake up i will be pulling the controller apart i guess and tracing the wires that shorted back to the board to see if my limited knowledge can save me a couple hundred dollars

 

[Adrian_]

There are better controllers than Sabvoton but they typically cost more and don't have 5 pin display support. Most of them have a hall/speed signal for basic displays and that's it. I believe Sabvoton is the only reputable 150a controller with a full 5 pin display support.

If you're lucky, the short could've caused a chip to crack or blow and should be easy to spot which one with a naked eye, otherwise you will have to start tracking wires and PCB traces, maybe even have to reverse engineer the controller to figure out what could've died.

 

[E-HP]

Its upsetting to think that one little short would kill such a major part of an ebike. Is there a better brand of 72v 150amp controller out there that would work with the display and throttle and everything i bought with the sabvoton? I'm guessing no. I am regeetting the money ive already spent on thos project.

You may be at a crossroads for deciding whether DIY ebikes are right for you. It's a hard lesson, and the tuition is high when you mess up, but you can't expect the manufacturer to protect you against yourself. If it were your house wiring, you could have killed yourself or burnt your house down, but you probably wouldn't place blame on the equipment, since you either learn a lifelong lesson at that point, or call a professional the next time and skip the DIY. You decided to jump into the deep end of the pool, and mistakes at 72V+ are costly, and you still have the chance of burning your house down during charging.

 

[eee291]

I hear Nucular has excellent protection against shorting pins like halls throtle etc.

 

[DeadEyeDave]

:thumb:

Its upsetting to think that one little short would kill such a major part of an ebike. Is there a better brand of 72v 150amp controller out there that would work with the display and throttle and everything i bought with the sabvoton? I'm guessing no. I am regeetting the money ive already spent on thos project.

You may be at a crossroads for deciding whether DIY ebikes are right for you. It's a hard lesson, and the tuition is high when you mess up, but you can't expect the manufacturer to protect you against yourself. If it were your house wiring, you could have killed yourself or burnt your house down, but you probably wouldn't place blame on the equipment, since you either learn a lifelong lesson at that point, or call a professional the next time and skip the DIY. You decided to jump into the deep end of the pool, and mistakes at 72V+ are costly, and you still have the chance of burning your house down during charging.

I do kind of place some blame on the manufacturer because the metal tabs in the connector were bent to the side. I realize that ultimately it is my responsibility. I know i said i am no electrician but i like to think i did enough research into the battery that i purchased not to burn my home down in the process of charging it.

There's a bunch of advice in this thread that is doing me no good. thanks for the warnings guys, i was hoping for someone who might have been able to give me advice on how to fix this issue. Gatekeepers gatekeep i guess

 

[E-HP]

I do kind of place some blame on the manufacturer because the metal tabs in the connector were bent to the side. I realize that ultimately it is my responsibility. I know i said i am no electrician but i like to think i did enough research into the battery that i purchased not to burn my home down in the process of charging it.

There's a bunch of advice in this thread that is doing me no good. thanks for the warnings guys, i was hoping for someone who might have been able to give me advice on how to fix this issue. Gatekeepers gatekeep i guess

Ya, but we all made the decision to buy a bunch of cheap Chinese parts to put an ebike together with them. And we all have learned, or will learn, that there is not a single cent spent on cheap Chinese parts that doesn't need to be spent in order to send it out (without any documentation of course). We also know that there are no standards, for wire colors, order, connector style, and if you hear something rattling around, you'd better open the component up, so the loose ball of solder doesn't short it out when you plug it in, or worse, when you're 20 miles from home. Geared motor? Better open it up to add the grease that should have been there. But heck, it's cheap.

For your Sabvoton, be patient and the calvary should arrive at some point, it just the respondents so far don't have experience with the controller, and can only offer trouble shooting advice (i.e. BMS, etc.). My guess is that the low voltage (5v) system or chip got wiped out. I bought a Sabvoton once and the 5v was dead, or died, or partially died, so I returned it, so the suggestion that they are sensitive seems right. When it died, or partially died, the display wouldn't work, but oddly the bluetooth module would connect, but couldn't read the controller parameters.

While you're waiting for the calvary, if you want to read about that issue or how to repair it generically (not Sabvoton only advice), type in LM317 in the search and reach a couple of those threads, since it's seems to come up a lot.

EDIT: If it's the alarm wires, it may be 12v, not sure. That would be a different chip. If the MCU is fried, it's all over. You may be able to jump the display connector to turn on the controller, just to see if it fires up, but I'm not familiar with the controller, or if it uses a separate ignition switch.

 

[MangDav]

From what I understand, you tried plugging in the alarm unit into the alarm output and the connector shorted? That is really bad luck as the Sabvoton doesn't need the alarm unit to function and most Sabvoton suppliers/dealers don't even include the alarm unit with the controller to begin with so this could've been avoided but damage has already been done unfortunately.

The alarm works off the battery voltage so when you shorted the alarm pins, you shorted the battery voltage which is 72v nominal, probably closer to 84v if the battery was fully charged hence the big spark. Unfortunately as stated by others, the Sabvotons are very sensitive and has no protection or fuses, when you short anything, 9/10 times something is going to die. I haven't dealt with such scenario like yours before, typically only DGD2110 chips which are half bridge drivers or regulators die in these Sabvotons as they are built very well as long you don't short them so I'm not sure if I will be able to help especially without being able to handle the controller physically and use an my oscilloscope or thermal camera on it.

If the LED is not turning on, typically this is a bad sign as it's controlled by Texas Instruments MCU called TMS320F2802PZA-60, it's a CPU that rans the whole controller basically, it runs on 1.8v so I can see how shorting 72v could damage the chip. I never had to replace that chip however it has flash memory on it which I have no idea what it contains, if it contains software uploaded by MQCON/Sabvoton then that chip can't be simply replaced. Normally if the LED is turning on but the controller is dead, then it's just a dead regulator which can be easily bought for few cents and replaced in few minutes.

That controller has hundreds of components on it and it would literally take hours to explain which components to probe and what results are expected. Shorting battery voltage could've killed anything compared to for example shorting throttle connection or high brake connection as those connections are pretty isolated and easy to trace. If you have someone or a business locally that repairs PCBs or electric components, I would give them a call and ask them if they have thermal camera. They could power up the controller and put it under a thermal camera and see which components get abnormally hot which would indicate that it's faulty. It's typically a lot cheaper than asking them to trace faulty components as it can take hours versus putting it under a camera for few minutes, they might even be able to replace it for you. You could also open up the controller and see if you can spot any blown up components or soot but I wouldn't hold my breath, I repaired around 30 sabvoton controllers and I only ran into two that has physical damage that I could spot without any tools, typically it's internal damage.

EDIT: If you do open up the controller, make sure to leave the controller unplugged for about ~15 minutes to make sure the capacitors fully discharge or discharge to safe voltage, also the bottom side of the PCB, the side which is held onto the case with 4 allen keys is a massive heatsink covered in white goo which is thermal paste, I would hold onto the PCB by the side otherwise you will be fully covered in that stuff and it's hard to get it off.