Smart pie motor broke down after two days - *FIXED*

[thomab]

Hi,

I received my Smart Pie last week, and I assembled my bike this Saturday.

I was very excited when I got it. It was properly packaged and looked to be in perfect shape. I have to say the assembly was quite easy. Everything fit properly on my bike at the first try, though I did have to modify the RAK-1 for attaching the battery to the bike.
Very good work! I tested the bike and played with it for a few hours, and it worked like a charm. Easy to go anywhere with just
some minor pedaling. See the attached photo for a picture of the beauty.

Unfortunately today when I was biking home from work, the bike suddenly stopped to work completely.
There was no life when I push down the throttle. Even worse is that the motor is now constantly braking, so it is impossible to
ride it as a normal bike. I had to walk home. The motor even brakes when the battery is pulled out, so I am certain it is something wrong
with the motor.

What should I do? I could try to open the motor, but I do not want to void any warranty.

Thomas

[Bikemad]

Hi andto the forum Thomas,

From your description, it sounds as if the controller has failed and will need to be replaced.

You will need to contact your supplying dealer and explain the problem to them.
If you purchased it direct from GM in China, I suggest you send an email to David (wyh@goldenmotor.com) and tell him your controller has failed and the motor is now stiff and jerky to turn.
Gary mentioned earlier that GM China are on holiday this week, so you may not get a response until next week, but please keep us updated with your progress.

The controller itself should be relatively simple to replace after the wheel has been removed from the bike:

• Remove the five countersunk Allen bolts securing the cooling fan/disc brake mount (you may need to remove your disc if you cannot easily access these bolts) and then remove the fan assembly
• Undo the six Allen bolts securing the controller's heat sink cover assembly
• Carefully slide the assembly off the axle (If the cover is sealed with silicon, you may need to use a sharp blade etc. to carefully prise the joint apart first)
• Unplug the three separate phase wires (make a note of which colour wire connects to which contact if it is not already clearly marked)
• Unplug the block connector and wiring coming from the hall sensors

Fitting the new controller is basically a complete reversal of the above procedure.

Alan
 

[GM Canada]

An excellent post by Alan as usual. If you want something a little more visual, I created a "How to" video a while back on swapping the controller. You can see its a fairly easy process.

http://www.youtube.com/watch?v=ofXCj_Dd10U

Gary

[thomab]

Hello Alan and Gary,
Thanks for the warm welcome!

I sent an email to GM China yesterday, and today I got a reply saying that the technical team was indeed
away on vacation this week. The quick reply seems promising to me, I'll keep you posted.

[thomab]

So I since I am impatient, I decided to open the controller and try to figure out what is going on.

First of all I'd like to point out that the controller is not identical to the one in the MP3, it seems like GM has made some improvements.
There are no screws connecting the phase wires to the controller anymore, there are some sturdy connectors. Don't know what they're called
in English, but in Norwegian they're "shovel plugs". The exposed parts of the PCB were covered in silicone, for what I assume is for keeping dirt and water out.
It looks like GM did a really god job here to me, I would have tough time imaging any water from rain etc creating any problems.

I also figured out what is wrong with my controller, or at least I identified one broken component. One of the power mosfets is shorting from drain to source, while the remaining 5 do not. I assume that this makes my wheel feel jerky when I rotate it.

Looking at the heat sink, there is a very suspicious pattern. There are 5 nice prints of the 5 mosfets that are functional, while the spot for the failed mosfet looks very different. I suspect that the failed mosfet has not had a proper connection to the heatsink. I am running with a 48v battery, so with a bad termal contact perhaps this was too much for the Smart Pie.

I am considering just buying a replacement mosfet and applying some thermal paste for all the mosfets to improve heat conduction, but I really hope I can get a new controller from GM china. I'm also afraid that something else might have been damaged, also the controller was a bit challenging to open (because of the sturdy design).

I think the internal controller for the Smart Pie actually looks great and feels really robust, I hope this is just a hiccup. I'll advice GM china to have a look at their heatsink design as well, then hopefully they can perfect the design.

Edit: Seems like the power mosfet provider has changed from ST as well. The new device is an international rectifier IRFB3077PbF.
 

[Lollandster]

Hi thomab. Since you happen to be a Norwegian who have recently bought a smartPie, just like me, you might be able to help me. Would you mind sharing your tracking number or at least the tracking results from your shipment? I am trying to understand why my package hasn't arrived yet after 24 days in transit and your tracking information might shed some light on that. Mainly I would like to know if your package left china trough Shanghai. Thanks.

As for your mosfets. I don't know exactly how a controller works, but wouldn't an open mosfet be better than a short circuited one (as in removing the broken mosfet) or would that lead to an open H-bridge disaster resulting in six dead mosfets? I don't remember the details about H-bridges right now, but I do know that the design I used a while ago didn't like to be hanging without input, but I can't remember if removing a transistor is bad. I do not see any benefit to removing the broken mosfet anyway as I guess one of the three phases on your motor won't be working without the last pair of mosfets. But it might free up the wheel. It's probably best to get a new mosfet or six.

If you decide to swap out your mosfets with something better be sure to write about it, it would be valuable information.

Thanks for the pictures, they might come in handy if I get problems with my motor, (if it ever gets here).

[thomab]

I ordered my package on September 6th. The battery got shipped via EMS, and the kit got shipped with TNT.
I see that my battery, according to google translate, "Leave the treatment center, sent to Oslo" from Shanghai on Sept 13th, and next entry
is on Sept 22nd when it arrived in Oslo. Then a couple of more days in customs.

I believe the kit arrived 4-5 days later.
I'm sure you'll get your motor soon.

[Lollandster]

Thanks, I guess my kit was sent by boat then as if it was a battery.

[thomab]

I spoke with GM China, and they have now shipped me a new controller free of charge 
I will also return my old controller to them, so that they can investigate what happened.

I think this is how customer support should be, and I'm happy with it.

[Lollandster]

I spoke with GM China, and they have now shipped me a new controller free of charge 
I will also return my old controller to them, so that they can investigate what happened.

I think this is how customer support should be, and I'm happy with it.

Good for you and good for GM China. They eventually came trough for me also and contacted EMS. I still don't know what went wrong, but now my package is only 30km away from my house. I am now happy with GM China again. I just hope my SmartPie controller survives longer then yours.

Are you going to ride your SmartPie in the snow? It's just below freezing outside now and my car has a thin layer of ice on it. I think I'll have to buy some studded tires. If the SmartPie can survive a cold Scandinavian winter with tons of salt on the road then all is well.

Obviously you don't need it anymore, but elfa.se has the mosfets: https://www.elfaelektronikk.no/elfa3~no_no/elfa/init.do?item=71-374-74&toc=19199&q=IRFB3077PbF

[MAGICPIE3FOCUSPOWER]

Do you have a picture how the motor wires are connected to the PCB?

[rcnicke]

Hello,

I won't bore you with all the quality problems I've had with the smartpie since I started using it last week. I'll talk to Golden motor about that.

Instead to the point; I want to open up the heatsink to access the controller to check if all the cables look ok and connected, because it is not working very well.
However, the heatsink won't come off!

Any help on removing the heatsink?

I was actually going to post on thomab's thread "Smart pie motor broke down after two days" since he obviously got the thing apart. But the new member rules only allowed me to post here.

Niklas

[Bikemad]

I was actually going to post on thomab's thread "Smart pie motor broke down after two days" since he obviously got the thing apart. But the new member rules only allowed me to post here.

Hi Niklas andto the forum.

I've confirmed your account and moved your post here where you had originally wanted to post it.

After looking at the above pictures, it would seem that Thomas had to use a bit of force to remove the controller.
I presume they are sealed with silicone sealant, which can really hang on tight sometimes, perhaps a groove and a thin rubber "O" ring would have been a better choice for sealing the joint as it would have been much easier to remove the cover assembly.

I suspect Thomas may have used a small flat bladed screwdriver to prise the joint apart just like Gary did in his video.

Alan
 

[rcnicke]

Thanks Alan,

It is really hard to get something under the heatsink, as there are flanges also on the rotating part of the motor, flush with the heatsink.
But I've used two screwdrivers, one opposite one another and pried very hard, to the point where I feared of breaking the weakest of them. And it's not that weak.

I also don't want to damage the motor, so I don't dare pry any harder, and cannot until I get a stronger screwdriver. You can see in the picture several dents on the flanges surrounding the heatsink, from the prying. It won't come off!

[GM Canada]

It would seem by your picture you are actually trying to remove the cover. The heat sink in my mind is the back of the controller which is behind the cover plate. Have you seen this video. About 1 min and 20 seconds in I remove the cover on a MP3. I assume it would be a similar process for the Smart Pie. I don't think it would ever come off by simply prying it. It think it would take the force shown in this video.

http://www.youtube.com/watch?v=ofXCj_Dd10U&feature=plcp

Gary

P.S. I am doing ths on my iPhone and the pictures are small so I could be completely misunderstanding the situation.