S06S Controller Failure

[Singlespeed10]

I just built a Euro-spec Pedelec for my wife with her existing hybrid mountain bike and parts purchased from BMSBattery.com – no issues with the order which was fast, smooth, and accurate. I have a Bafang 500W BPM motor, 36V – 15A Li-Ion battery in a AL case, and S06S 250W sine wave controller. I am deliberately under powering the motor to maximize longevity. This spec with the PAS is perfect for my wife to keep up with her compulsive, roadie husband.

Issue

The components went together easily, worked great, and then quit after less than 100 miles. On one ride we briefly noticed (1 second) and electrical burning smell after topping a short but steep hill - no obvious negative effects were observed. On a second ride we noticed the same brief burning smell immediately in the middle of a short, steep climb after which the unit immediately failed. The LCD1 display intermittently indicated 06_Error which means “Motor or controller has short circuit Abnormality”, according to the user manual.

Troubleshooting

I have tested a number of things and now believe that one of the controller Mosfets failed. Here’s what I did:
1. Dismantled the motor and found no obviously burned wiring.
2. Tested the motor halls and observed the proper switching from 0 to 5V for each as I spun the wheel http://www.ebikes.ca/documents/HallSens ... gFinal.pdf
3. Tested the controller Mosfet continuity per http://www.ebikes.ca/documents/BlownMosfets.pdf and found the following:

Phase Pos Neg

Green 0Ω 11KΩ
Yellow 21KΩ 11KΩ
Blue 21KΩ 11KΩ

From this I conclude that I have a blown Mosfet on the green phase. In addition, the motor is harder to turn with the controller connected which Grin also states is an indicator of a blown Mosfet. However, there is no obvious burning on the Mosfet or any other controller component.

Questions

1. Have I missed something? Am I correct that this is a Mosfet failure?
2. Was this a fluke, did I do something wrong, or did I deserve this because this is a really crappy controller. I don’t want to spend a fortune on a new controller for what is a rather power modest requirement, but I don’t want to replace it after another 100 miles either.
3. Should I just replace the Mosfets with IRFB4110s? Any advantage to getting branded ones for $5/ea. at Digikey? Or are the eBay Mosfets from China OK at about $1/ea.?
4. Controller replacement choices that I have considered:
• BMS SO6S: If this was a fluke and this is a reasonable choice I’ll buy another from BMS: $24 + $35 shipping = $59.
• BMS S12S: I’d get this if it is more robust for my application (12 Mosfets) AND I can set it with the LCD display to limit the power to ~250W: $34 + $ shipping = $69.
• Cellman 6 fet IRFB4110 Infineon controller http://em3ev.com/store/index.php?route= ... duct_id=78 with the ability to program it using XPD open source software viewtopic.php?f=2&t=27927#p403201: $76 + $25 shipping = $101.

Any assistance will be appreciated.
Singlespeed10

Posts: 1
Joined: Sat Aug 24, 2013 9:40 pm

 

[trex]

buy a couple of mosfets from China.

 

[Deere John]

Sorry to lift this old thread but I have the same question!

Have used kunteng KT-controllers and their KT-LCD5 and KT-LCD3 display. Now using BMS S06S controller (with the same LCD, actually the same as S-LCD).

But I'm tired of the controller failing me so I was thinking about buying a better quality controller. Have found the Infineon controllers and they look nice.
http://em3ev.com/store/index.php?route=product/product&path=38&product_id=77

But... can I still use the display for that controller? Or do I need to buy their 3-speed switch instead?

Or maybe there is some other good controller?

 

[Deere John]

...and today I think I killed another one. Was biking in some terrain and this controller really doesn't like that. Have been through a couple of these now. Just curious, have something happened on the market last year or is this still the best standard controller to get?

 

[Deleted member 4366]

That's weird. I've never had a problem with a KT controller, nor have any of my friends who use them. Maybe there's something not right with your motor or something else.

What code number is on your BPM?

What current do you run?

Does the controller get enough cooling?

S12S would be the controller that most people would use with a 500w BPM.

 

[Deere John]

Ok, today I fixed this.

First I had to solder a little to get the new S06S fitting all connectors:

Then measured my old controller: , and the new controller: .

It was completely dead the broken one. The 5V didn't lit at all. The new one had the 5V LED flashing and when pedalling/throttling the controller lights flashed.

Disconnected the tester and connected everything for real and it worked, everything, as it should.

Took a test ride a few kilometers and it worked, as new.

Very strange. But well, not the first time as you see. Usually the power output part use to break down, but now it seems like it was the low current part!? Don't know, don't care too much, don't thinking of opening it up this time. I will just have this bike working now and never bike hard terrain again. It surely is underrated for that sort of conditions. I have a new fatbike with Bosch CX-system on it that can take care of those conditions exceptionally now. So, this will be a road bike with some gravel. Then I think it would last long without problems. This is actually the only big problem I have with this bike, otherwise it has lasted very long (soon 10000km!) and been through alot of abuse! So I think I love it anyway

That's weird. I've never had a problem with a KT controller, nor have any of my friends who use them. Maybe there's something not right with your motor or something else

Don't think so, this motor have run 8087 kilometers now, this is the second bike I have these electronics on. Battery and Motor is the only thing (well, throttle also) that I've had from the beginning. That could be if there might be some bad isolation somewhere and when the current goes up it gets some flashover or something. But I don't know.

What code number is on your BPM?

code number? Don't know, there is some marking on the side. See photo.

What current do you run?

No idea, don't remember what I got, but I have a feeling it might be on the limit when pushing it hard (eg, when it's though for the motor and goes very slowly also = bad cooling).

Does the controller get enough cooling?

Well, I have it in a saddle bag. It gets hot but not burning hot like before when I had it inside the battery compartment they use to last now in the saddle bag.

S12S would be the controller that most people would use with a 500w BPM.

My motor is rated 250W @ 36V so I went for the S06S rated for 15A.

 

[Deleted member 4366]

The code number should be between the spoke flanges. It's the number in brackets:

 

[Deere John]

The code number should be between the spoke flanges. It's the number in brackets

late answer, but first I didn't know what to answer and then it kind of slipped away. But anyway, more problems now so...

I don't have such number on my motor. But I have figured out what BPM means. It is a Brushless Permanent Magnet Motor yes. And I have count the stuff myself, 20 magnets and 18 poles.

 

[Deere John]

The problem I now have occours sometimes after half an hour ride or so, when battery is about half empty. Always in heavy load such as a steep uphill. The engine starts to "choke". First with long interval such as, drive half a second, choke half a second. And then the interval decreases so it is unrideable after a few seconds.

I first thought it was due to my old battery when it first happened. But it also happens on my newer battery. It sounds like something mechanical and the motor seems to jump just a little. Maybe it could be something with a clutch or something like that?! I don't know. If it would be electrical shutof I guess it would behave the same if the motor current drops and flushes on again.

Very strange. Anyone had this kind of problem?

 

[Deleted member 4366]

Your problem is electrical. Check all the motor connectors are tight and that the one near the motor is all the way in. If it's the 9-pin type, there's a line to show how far it has to go.

The difference in the motor that gives the speed is the windings. They all have the same number of poles and magnets.