Finally got my Gem working after a lot of help from some awesome members here. Was going down the street and heard a clunk in the motor. Took the motor to local repair shop and they sent a pic of the part that needs to be replac
Technically, that is the encoder, but I guess it could also be called a position sensor.
I’m not sure they just fail/stop working.
I have many questions than require more of the story…
Did the cart stop running? (tow home?)
What were you doing at the time of failure?
What made you focus on the motor?
It sounds like you removed the motor and took it to a shop?
How did the local shop determine this is the part you need?
Did they show you the part? Was it damaged?
Replied within the quote. Thanks!
From my RISearch this seems to be the part from the picture the mechanic sent. Not sure if that is correct. Will try and get the part tomorrow to confirm.
I read the main issues that could cause the sensor to break, is electrical issues with the sensor or physical damage. Motor was not damaged.
If you would have checked in here before you took the motor out, I would have pointed you to the motor controller. It has a status light that might have been blinking an error code as to why it had faulted. It might have saved you the effort of pulling the motor.
I don’t know how the shop figured out it was an encoder issue without actually hooking the motor up to a controller and attempting to run it.
I isolated the motor from the gear box and it was seized up when pressing throttle.
I believe that motor is open ended (It only has one bearing). I don’t think you can actually bench test/run it without being coupled to a gearbox or fixture that can support the free floating coupler end (It might be possible if you stand it up on end). Your observation that it was seized up might have been the rotor simply dragging on the stator pack because the coupler was not supported.
The code I had was 11 “Encoder fault, Check encoder wiring and encoder, repair as needed.” I also had the 8 “Motor or Controller too hot or cold, reduce load, install better heatsink or fan, check
thermistor wires to motor” the 2nd one occured during the testing on my property(the Sevcon was hot to the touch).
I used the opportunity to take the CV joints off to replace the boots. I also wanted to check the gearbox to check for any damage(metal bits, etc), that seems good.
I had no idea it’s not possible to bench test these motors. Or that they will not spin properly if not attached to a gearbox. That does make me wonder how the mechanic diagnosed the issue. There business is strictly electric motors so maybe he has the equipment to test it. Will have to check with them next week as Friday might as well be Saturday here;)
Thanks for your input.
Got the motor back with the new encoder and it is working on jack stands. Don’t want to test it on the road until I see if there is more testing I can do first.
I spent a couple of hours trying to see if anyone else on the forum has had this issue and what can cause it. No luck, except the main causes of encoder failure in general online.
If anyone has any ideas for what I should check?
Recap: Everything was working well. Testing on the road to 43mph. Came back down the road off a small bridge(maybe 7% decline), loud thud, motor turned off, controller gave replace encoder error, cycled key, was able to get home. Tried at home(motor seemingly seized up), not moving, controller shut off for overheating error.
Just prefer not to have to spend more $$ if it repeats, if there is something I can check fix first.
Encoders never fail. Imo. What year Gem? Picture of motor? Is motor seized? Car rolls with key off?
I took it to a local motor shop they had me buy a new encoder, they installed it. I reinstalled the motor yesterday and tested on jack stands. Everything is working, no Sevcon error codes.
2013 Gem chassis, frame, 12.1 Spicer gearbox.
Motor is AMD 8KW motor I bought from Bad Brad. You supplied the throttle which is working now, thanks.
Picture of how it sets right now.
I am hesitant to test it on the road since last time everything seemed good then the motor failed.
How charged was the battery at that time?
If fresh off charge, it is possible that going down the steep 7% downhill used enough regen that it charged the battery high enough to trip the OVP(Over Volt Protect) and the BMS shut down the battery. Either that or the Over Current (Charge) setting is too low. With no place to dump power it might have spiked pretty high and no place to put it.
But it was only a small bridge?
Keep track of your battery voltage. If battery is close to a full charge, avoid high speed downhill runs.
Battery is right around 80%> I haven’t bothered charging it as I am not going far during testing.
I will check the settings and see if when I test it if it goes above the settings.
Yeah, small bridge, maybe 7% angle. Its not like I was accelerating into the downside.
The knock that happened after going down the bridge was strong, shook the Gem, shut the controller off. I wasn’t able to tell where exactly it came from(motor, gearbox). I really don’t want it to happen again(cost me $700 for motor shop and encoder), so hoping I can find the cause before I test again on the road.
I got the term wrong, the part is actually a hall/speed direction sensor(its on the top of the AMD motor held with one screw). Here is the link to the part I replaced it with in case someone in the future needs it.
The Gem is on the jack stands now and works(no controller errors). I did read from another e-forum where members had issues with non branded(i.e. not honeywell) sensors. Maybe AMD uses cheap sensors. Since this issue doesnt seem to come up on here, I am wondering if it is some other issue(controller, electrical, mechanical). I may just take it back in the road to see if I have the issue again if there is not more troubleshooting/testing I can do first
Unlikely there was a motor/encoder issue. Did you try driving the car after resetting? Ie. power cycling.
The trouble sounds like what we call cavitation. Only known to happen when requesting too much torque, Such as mashing pedal or starting on hills. I can’t get my head around cavitation with neutral braking. Ie. regen
Help?
@MikeKC
@djgabriel2004
Cavitation can be violent. Like instantly switching forward reverse. Under acceleration it is easily controlled by using less throttle.
If regen cavitation is even possible, less throttle would make it worse.
Only an informed guess.
If true, knowing this may allow you to determine the cause. Do you have a high level of regen? Decel when lifting foot from pedal.
I feel responsible as it is likely that I programmed the drive profiles.
Time permitting, I will look for a “Badbrad” file that I may have saved. Mikekc may recall as well, if he was involved.
interesting. The electric motor shop said it was the sensor, I bought it, they replaced it, and it works now on jack stands. Maybe they are trying to screw me?, but if they were they probably would have bought the sensor and upcharged me to put it in. My sense is the sensor did get damaged, the question is what caused that to happen on a brand new motor and programmed controller that has not been driven more than a mile?
Is the motor really only attached with 3 bolts(there are 6 connection points)? that is what came with it(it seems tight). Thats alot of weight on the gearbox spline.
After the cavitation(which does sound like what I felt/a strong jolt and bang), I was able to drive home down the road(slowly after cycling key(that controller gave the encoder error fault). Once home, I tested again and the controller gave off the overheating fault. After a couple of tests with the motor installed, I decided to try and isolate it and run the motor not connected to the gearbox. It wouldnt spin(Byron says the motor will not work if not connected to a gearbox). Thats when I took it to the local motor shop.
You sent the 2nd controller(after I blew up the first one>from badbrad) and that was programmed with the throttle I bought from you(I was finally able to get this to work after I installed the resistor!)
Difficult for me to say what level of regen I have as its my first electric motor. I was not pressing the throttle going down the bridge(travelling around 30mph).
Tried to upload a video of the Regen but doesn’t allow me. Without anything to compare it to, I would say it seems in proportion to acceleration.
Unless anyone has any more testing suggestions I am going to run it on the road and 
that the issue doesn’t repeat.
If same as acceleration, that is high. Reason for not being able to test out of car: Motor only has one bearing. Out of car armature rubs. It may also hit encoder. That’s a thought! Did you rotate armature when out of car?
Maybe it is not the same as acceleration, and especially not as much if the throtte is pressed past 50%. Maybe I can upload a video to YT and post here as the forum doesnt seem to support videos.
I did try to rotate the motor not connected to the gearbox, which makes sense why it did not spin. I guess that could have been the reason the sensor was damaged.
Not much help now, lol. I wish I could get more information from the controller. Especially before I test it again. Is purchasing the dongle from Thunderstruck and the software the only way to get the data/settings?
I am committed to getting this Gem working!
Much cheaper dongles and dvt sw from France or Australia. Iirc. Sometimes on ebay. Called ixxat .
Ok. I am more mechanical and hardware inclined. I read that it is quite challenging to program. Can I use it for read only purposes to see the history(errors, etc) and confirm the settings are correct? I would need the file with the settings for my setup.
