BBS02 750W controller dead

Hi All, new BBS02 750w Mid Drive owner here. I installed the kit I ordered from Paul at EM3EV two days ago and yesterday put 32km on the bike.
It was a blast...lots of power, plenty of speed...then..I fired it up this morning to ride to work...hit the throttle....lunged and died.
After googling and joining the forum it looks like it's the FETS in my controller as well....only a slight clicking sound in the motor..no power from throttle or PAS.
Paul has been a great communicator and excellent to deal with....I've sent an email this morning but I understand he's travelling so I probably won't hear back for a day or two.
 
I heard back from Paul at EM3EV. He's travelling right now, but he's sending replacement controller under warranty right away. He said that it is a limited issue and has only happened with a few units out of thousands that are on the road. Seems to me to be just a bad batch as the three of on the forum that it has happened to all seem to be within the last month or so. I have faith in the unit, it seems very robust and Paul at EM3EV is a stand up guy for sure.
I'll post back when the replacement is installed and I'm back flying through the woods!! :D
 
ac246 said:
Succesfully repaired my blown controller. It was just clicking when pressing the throttle, or when turning the pedals, or when pressing and holding the walk assist. I removed the controller and removed all of the rubber around it. Then identified the faulty FETs and ordered the exact same ones. P75NF75 and soldered these in their place and now it works brilliantly. Have reprogrammed it from the computer so now it starts gently and also limited the controller to 18A.

I spoke with a friend who is an electronics engineer and he said that one of the FETs will be shorted and causing the overload circuit to turn off the power. Which is why there was an initial click.

Once I took them out I noticed it was only one of the fets on the blue phase that was blown but without taking them out I would not have been able to tell. So I replaced all three. Cost me about £3 to order them on ebay but they would have taken 30 days from china so I also ordered some off of rapid electronics here in England for £15 with next day postage for 9 of them.

Hopefully this will help someone else repair their burnt out controller.
Click to expand...
I love that there are those of us just unhindered by what everyone else tells you. It is how we move ahead in all things. Great job ac!
 
If there is anyone that has their dead 25a controller after being replaced under warranty I'd love to get my hands on the dead one. Why? Because the dead one I have is only a 20a controller. So if I'm going to rip into a controller anyway why not try to upgrade mine a little from 20a to 25a? The cost for the FETs is likely the same and the degree of work is too. So if anyone has a dead 25a controller they are going to trash please PM me.

Bob
 
Are these new 9FET controllers that are failing?

I've got an old 6FET controller and bought the drive with the intent on running an external controller to remove a heat source from near the motor and increase the total thermal dissipation capacity of the drive ( therefore, i can either take increased efficiency, or just pump more power in - similar to running a magic pie with an external controller ).

If these are 9FET controllers popping, we may be in the same boat with internal controller hub motors. There is an issue with reliability even within stock limits.

Maybe you guys should start thinking about external controllers as well. Not just for reliability, but for increased power or efficiency as well.
 
neptronix said:
Are these new 9FET controllers that are failing?

I've got an old 6FET controller and bought the drive with the intent on running an external controller to remove a heat source from near the motor and increase the total thermal dissipation capacity of the drive ( therefore, i can either take increased efficiency, or just pump more power in - similar to running a magic pie with an external controller ).

If these are 9FET controllers popping, we may be in the same boat with internal controller hub motors. There is an issue with reliability even within stock limits.

Maybe you guys should start thinking about external controllers as well. Not just for reliability, but for increased power or efficiency as well.
Click to expand...

No I think everyone so far is talking about the older 6 FET controllers. And it may not be 100% the controllers fault. In some cases at least it is the way they were programmed ether at the factory, by the seller or everpn by the user.

Bob
 
Forgot to say, in relation to neptronix, I have done exactly that. Just ordered a new external controller and cycle analyst to modify my bbs02. I have started another thread which I will update when it arrives.
 
Ironically it seems that the 9 FET has been more problematic than the 6 FET. Hopefully just a batch issue. No comfort for those who have the new 9 FET drive though.

Looking forward to seeing some external controller and CA conversions. It will be a shame to lose the compact config that you get with the internal controller but a huge advantage having the CA to monitor things rather than relying on the useless stock display. I hate not having true consumption available.

I have already proven that the stock PAS sensor in the BBS02 drive will work with a CA3 so at least this can still be utilised if you want to keep the PAS function of the drive without fitting an external PAS. Should be noted that there is very little room to fit an external PAS ring on the BBS02 750W drive. I tried this too but without any luck.

For those interested, there was a thread on converting the stock controller to operate with a CA3. Unfortunately, not too successfully however plenty was learnt from the experience.
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=60433&start=25
 
Nice repair job!

If the FETs blow, I'd suggest replacing all of them with better ones. It sounds like the underlying issue is the software allows destructively high currents under some conditions. Using FETs with a lower Ron will reduce the heating somewhat. There are some pretty good choices out there these days.
 
fechter said:
Nice repair job!

If the FETs blow, I'd suggest replacing all of them with better ones. It sounds like the underlying issue is the software allows destructively high currents under some conditions. Using FETs with a lower Ron will reduce the heating somewhat. There are some pretty good choices out there these days.
Click to expand...

I was wondering if the gunk they have around the controller adds to the general heat buildup. I realize the FETs are being shocked and blowing. And the controller is connected to the alm. Cover to help dissipate the heat. But enclosing them in the gunk can't help.

Bob
 
Actually, in most cases the potting will help with heat dissipation. It conducts heat better than air.
 
CONTROLLER DEAD AND FIXED AGAIN!!!

I was out for a nice ride up in the North Yorkshire moors, when while pushing the bike as going up a hill I was using the throttle to help get the bike up the hill as I couldn't keep the walk mode button pressed as it was very bumpy. As I got to the top, I got back on the bike, pressed the throttle gently. And as rolling back slightly I pressed the throttle gently to set off when the motor made a noise as if it was not spinning and then the click of death. About 5 miles from my house I was fairly annoyed. I have opened the controller back up and have identified which of the fets it was. It is the left of the three blue phase. And after testing the three fets I replaced before it is the same one that has blown. The other two originally replaced were fine. So this one fet has blown twice now.

Possible causes? I don't know this time as I have the settings on the motor very under specked. I have start current set to 1% and only just slightly pressed the throttle. Last time I had start current as 100%. Only thing I can think of is that maybe as the bike was moving backwards at the time that I pressed the throttle which causes the motor to turn by the pull of the chain. Whether this acts as a generator and somehow damages the fets I don't know...
Other possibility is heat! As fechter says, the potting material may have helped with heat dissipation... The case was fairly hot after it died. And my circuit is currently un potted.
If anyone has done this repair already then maybe undo the motor again and another some thermal grease between the heat sink and the casing...

My new external controller and cycle analyst 3 will arrive soon. Incase anyone is giving up on the internal controller, I'll be updating my other thread about how well it will work.
 
I've had 2 controllers blown on me already. The second was a warranty replacement from EV3MV. I thought I'd give the repair a go myself and it's worked! Total time was about 1.5 hours.

I ripped out the putting compound with a screw driver. It takes about 20 mins to get it all out. You have to be careful to not scrape the circuit board. I then used a multi meter set to 'Diode' / Audio mode which beeps when it detects a short. The first FET on the right hand side looking down on the controller had blown so I chopped it off and individually de-soldered each legs. I then re-soldered a replacement FET, fired it up and now it's works great. I also added some more thermal grease between the aluminium bar and the casing. I'm not going to replace the putting compound incase it blows again, just going to seal the outer case with black sugru and pop some silica gel into the half empty casing. The motor is now a bit lighter too. I've removed the throttle as I suspect this was causing the issue. I've ordered another identical one from Ali Express which should be here in a month or three.

Will be creating a build thread soon with pics of the bike etc.
 
First off please forgive my electrical stupidity when I ask this question. If it's always the same FET (or even more then one) that blows would there be a way to creat a protection for the FET like a quick blow fuse, fuse link wire or even a breaker? Something that could be accessed from outside the controller. While going with a 3rd party external controller and CA meter may work great for those who are capable of doing this conversion. Is there something for those of us who do not have the technically and/or financially capacity to do this conversion. "IF" there were a way to inexpensively install some kind of replaceable or resettable fusing device I think this would help a lot of us. I for one would have a technical problem installing an external controller and CA meter. But I do ride with the fear that this kit is someday going to die 20 miles from home. And there's just no way I would be able to peddle back without the motor assist. But if I could just pop in a new fuse and and ride off, Wow, would that be a great load off. Just a thought for the electrically gifted to help us DAs.

Bob
 
A fuse of the right rating might work, but I've generally found the FET will blow faster than the fuse, so the fuse only prevents it from burning after it blows.

It definitely sounds like some kind of design issue causing the problem. It may be difficult to tell exactly what without some fancy test equipment. Common fail modes include shoot-through, where the high side and low side of the same phase are on at the same time, ringing in part of the circuit, causing improper gate triggering or transient voltage exceeding the rating, overdissipation caused by excessively long on-time at low motor speed, and plain old overheating from excessive resistance losses.

Better caps on the power rails usually helps lots of things. These could even be mounted externally on the battery wires.

If the gate driver is sort of lame, it can cause problems. It's possible to damage the driver when the FET blows also.

If the pulse timing is off due to a software glitch, then all bets are off. Nothing in the hardware will fix that.
 
2 controllers dead? was one of them a 9fet? both?

gorndog said:
I've had 2 controllers blown on me already. The second was a warranty replacement from EV3MV. I thought I'd give the repair a go myself and it's worked! Total time was about 1.5 hours.

I ripped out the putting compound with a screw driver. It takes about 20 mins to get it all out. You have to be careful to not scrape the circuit board. I then used a multi meter set to 'Diode' / Audio mode which beeps when it detects a short. The first FET on the right hand side looking down on the controller had blown so I chopped it off and individually de-soldered each legs. I then re-soldered a replacement FET, fired it up and now it's works great. I also added some more thermal grease between the aluminium bar and the casing. I'm not going to replace the putting compound incase it blows again, just going to seal the outer case with black sugru and pop some silica gel into the half empty casing. The motor is now a bit lighter too. I've removed the throttle as I suspect this was causing the issue. I've ordered another identical one from Ali Express which should be here in a month or three.

Will be creating a build thread soon with pics of the bike etc.
Click to expand...
 
fechter said:
A fuse of the right rating might work, but I've generally found the FET will blow faster than the fuse, so the fuse only prevents it from burning after it blows.

It definitely sounds like some kind of design issue causing the problem. It may be difficult to tell exactly what without some fancy test equipment. Common fail modes include shoot-through, where the high side and low side of the same phase are on at the same time, ringing in part of the circuit, causing improper gate triggering or transient voltage exceeding the rating, overdissipation caused by excessively long on-time at low motor speed, and plain old overheating from excessive resistance losses.

Better caps on the power rails usually helps lots of things. These could even be mounted externally on the battery wires.

If the gate driver is sort of lame, it can cause problems. It's possible to damage the driver when the FET blows also.

If the pulse timing is off due to a software glitch, then all bets are off. Nothing in the hardware will fix that.
Click to expand...

To bad fuses wouldn't help. I am guessing the problem is a combination of things you mention. My "so called 750" that came with a 20a controller died after one block. But I admit In error I had it in 7th. Gear when it blew. But last weekend I let my son-in-law try riding my 500w with it's 18a controller. He never even looked at what gear the bike was in nor did he ever change gears. And he rode up/down the road 2 blocks each way) several times from a dead stop up to 25+ Mph and the controller had no problem with it.

Bob
 
neptronix said:
2 controllers dead? was one of them a 9fet? both?

Yes, both 9 FET. I also repaired the 1st 9FET and it blew again too after about 5 mins. I want to love this BBS system, I really do, but getting really frustrated with the amount of time and money I'm having to put into it. I was told that this system will run happily at 14s and it did for a while. I'm starting to think that It can't take that high a voltage, even though the FET's are rated to 75V.

All time one spends one the forum reading about other peoples experience means little until one tries it themselves.

I'm wondering if we can start to compile a list of system voltages and circumstances in which the BBS-0x system failed.
Click to expand...
 
I have been running mine on 14S LiPo for a week now, with no ill effects, on my November 2013-built 6FET Controller.

Have you reprogrammed your unit and can you post your controller programming settings? It could be that there is something amiss in the programming, which would cause your FETs to blow repeatedly. See setting at "Start Current (%)" - Should be set no higher than 30. If higher, that could be your cause.

http://endless-sphere.com/forums/viewtopic.php?f=28&t=58780&start=425#p942167

Also, the Caps are only rated to 63V, and the Controller's firmware shuts down above 61.5V, so 14S (or 15S, charged to 4.1V/cell) is about the max voltage you can run on the stock controller.
 
I just had another 9 FET controller give up the ghost... After the first controller went out we have been "babying" both of our conversions. During this fateful ride we used only PAS 1 and PAS 2 (the bike being set for 9 PAS levels) with no throttle over hilly terrain.

Please tell me where I can purchase replacement parts (FET's) and where I might find troubleshooting info.

Thanks!
 
Just read the entire thread and found that the mosfet part is a P75NF75.

Has anyone come up with a superior mosfet that might hold up better?
 
I assume most or everyone is buying the P75NF75 FETs on EBay. As many including me have asked "is there a better quality that can be used?". I assume the number " P75NF75" is a general number that is used by all MOSFET manufactures use. If this is correct maybe is just the quality of the EBay sellers that adds to the problem. Any possibility?

Bb
 
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