[Stephan]

Hi

My project is going through major upgrade but now unstable motor signal causing it to rev up uncontrolled directly when I turn on the car key switch.

Background: The key switch used to work fine and the car was driving reasonable although I did not drive in total more than 10k-20k test drives and the car was too slow to get approved/road worthy. Reason it was too slow for this 1400 kg car, was it was under-spec'd with only 120 Amp from my Leaf gen1 modules which is now upgraded to 240A.
Due to the battery upgrade the contactor and switching all moved to the side approx. 1 meter further. The wiring loom to Curtis 1238 and to Curtis trottle pot are extended, and I added connectors in between for this wire extension.

Current Problem and possible errors
1. BMS to Trottle pot wire - One of the 4 wires run through my BMS such that when BMS tells the battery is 'Critical bad' the car wan't drive. Now, that may used to be the paddle-interlock. I will need to check if I swapped it and now by mistake run the pot low or pot whiper through this BMS relay. Would that BMS wire cause the problem?
2. Electrical interference - Maybe lack ot wire shielding as it runs close to 12V-96v dcdc converter and close to contactor and main B- and B+ cables?
3. Symptoms : first time, the problem suddenly appeared when I first tested the motor running and car slowly drive on drive way 4 or 5 times up and down without a problem. Then suddenly the motor stopped driving whilst curtis display (840 model) without error code or it disappeared and I did not notice, I recall an error code 42 based on blinking red/yellow lights.
4.shortened wires or loose wire - problem did not happen first time when standing still but slowly driving. Also it was a very very wet day with, high humidity (wires are all well protected against the weather).With multi meter all wire connections I tested seemed fine with max of a few ohm resistance. But still, I don't exclude it yet from the problem.
5. next day - I tried again standing still and after a little wire wiggling a new symptom/problem. Key turns first all on without problem. I have the car in 'free' gear and ref up to 500-800 rpm and draw around 30Amp. Repeat this and at around 10 times it shuts off and returns a 39 error.
6. Next test (not done yet) I plan to do is to bypass the BMS. For this test I need to rewire that one wire to bypass the BMS. - I will post the outcome once I have tested this.
Any suggestions about next step and how to fix this problem?

 

[remy_martian]

1. What is the battery voltage?
2. What geartrain?
3. What car is it?
4. What motor are you using?
5. What are the lengths on the HV runs, battery to controller, controller to motor?

 

[Stephan]

1. What is the battery voltage?
2. What geartrain?
3. What car is it?
4. What motor are you using?
5. What are the lengths on the HV runs, battery to controller, controller to motor?

1 Battery=96v
2 mazda3
3 mazda Tribute
4 AC50
5 HV runs -what does that mean? I run 90mm2 thick, 1x3m connect to B-, 1x 3m from battery-battery (48v each), 1x 1.2m to B+ on controller. Length controller to motor approx. 30cm

 

[DMPstar]

1. What is the battery voltage?
2. What geartrain?
3. What car is it?
4. What motor are you using?
5. What are the lengths on the HV runs, battery to controller, controller to motor?

6. What BMS are you using and what kind of access to parameters and live cell and battery info do you have? Could your battery be low and on the cusp of cutting throttle during your driveway tests?
7. What model of throttle pot do you have, and has it been sitting in a location where it may have come in contact with water or excessive humidity?

Also it was a very very wet day with, high humidity (wires are all well protected against the weather)

Pots that aren't environmentally sealed, or even ones that are can corrode internally and give crunchy output, just like grandma's old tube radio. Electrical connectors and the pot internals should have dielectric grease applied in case you have not.

I recall an error code 42 based on blinking red/yellow lights.

42 = Throttle Wiper Low fault, also very close in number of blinks to 43 - Throttle wiper high fault, which I recall depending on the Curtis parameter setting for Throttle Interlock Type can cause the controller to enter full throttle output if one or more of the throttle wires is disconnected.

Now, that may used to be the paddle-interlock. I will need to check if I swapped it and now by mistake run the pot low or pot whiper through this BMS relay. Would that BMS wire cause the problem?

I'm guessing you mean "pedal-interlock" and "wiper". Yes this could cause the phenomenon I described above. Assuming since you are counting blinks and peering at a spyglass that you do not have access to PC Programming Station or a handheld Curtis programmer, so you wont be able to change this parameter, and likely when your BMS opens the relay to cut throttle, your controller will enter into a fault mode regardless of what signal wire you choose to connect to that relay. I would never use a throttle-cut low-battery relay for my own personal on-road vehicle. For one setup I have a bright strobe light instead, with plans for a buzzer also. I imagine a situation where I was asked to pick up some extra diapers and make some unplanned stops on my way home, hadn't run my battery to a low SOC for a while until that day and would not be aware if I had weak or imbalanced cells in my pack. Need to take a left turn (or in your case a right turn) and there is an oncoming bus, gotta floor it to get thru the intersection quick! I would rather get to a safe place on the next block to find a charger and give thanks for living another day than the possible alternative.

Electrical interference - Maybe lack ot wire shielding as it runs close to 12V-96v dcdc converter and close to contactor and main B- and B+ cables?

Good reasoning here, but factory harnesses for 1238 controllers I have used did not come with shielded throttle cables and I have not run into a situation where noise has caused noticeable trouble with them. It still may be possible in your situation, so moving signal wires away from the big wires is advisable.

Repeat this and at around 10 times it shuts off and returns a 39 error.

Have you waited long enough counting your blinks to make sure it is only outputting one error code? In many cases more errors are present, and some such as "39-Main contactor did not close" will result from and accompany another more pertinent fault code.
Is your main contactor coil wired directly to the controller as recommended by the manual?

 

[Stephan]

Great feedback. From what I wrote before, I m no expert, apologies for typo or wrong terminology, I learned over last few years bit by bit and got myself some tools: I have the curtis programming software and used it, not just spyglass. Also my Batrium BMS reads a healthy battery at each cell. Trottle pot is PB-6, was new out box 5y ago, always dry and no signs of rust. I don’t have under-cover driveway so the torrential weather and flooding in Eastern Australia slows me down coming days. A good time though to brush up my documentation which I can share with stats and settings from my curtis and batrium. Thanks again

 

[Stephan]

Also, some tech background, I earlier posted conversion details on Stephan's 2001 Mazda Tribute and my old wix blog.

Progress: I have not yet been able to connect my computer to read out the errors on Curtis. Yesterday I repeated a test, started (as normal/no issue), and repeated 10x ref up to 300-500 rpm without driving on the drive way. No issues. So it seems to happen when in motion.
In my situation, this is now harder to test because I am on a busy road and when I do a road drive test and get stuck I need some people to help push me.. all in all besides the rain not so great.
I am also cautious for repeat of error situation with high ref up without me pressing throttle.

8. condense build up? I recently witnessed at an electricians job that condense was building up in conduits and over time that causes a lot of water to drip at places it should not go. My Curtis wire loom is protected and sealed with a conduit but not very tight and in the gap water condense could build up. I have to check the connector and if the problem is on that side as I have not touched it for about 1.5 years. This loom connector check is next first thing for me.
9. throttle only with healthy HV battery/BMS "non-critical" - yes I will remove it, even only for just excluding it from a possible problem it is a good idea - thanks.

 

[remy_martian]

You appear to not have a ground connection between the pedal and the controller and may be getting ground connections through the drivetrain/bearings/suspension. Run a dedicated power and a dedicated ground wire between the pedal and the controller. Ground to chassis at controller only.

 

[DMPstar]

You appear to not have a ground connection between the pedal and the controller and may be getting ground connections through the drivetrain/bearings/suspension. Run a dedicated power and a dedicated ground wire between the pedal and the controller. Ground to chassis at controller only.

Are you suggesting running a ground from the body of the potbox to the body of the Curtis and then to chassis, or connecting a new dedicated "throttle pot low" from the potbox to its respective pin on the Curtis and then to chassis?

 

[remy_martian]

A pot has three connections. Ppsitive, negative, and signal. All three should run directly to the Curtis. Any grounding at the Curtis, not the potbox. Ideally running inside a grounded shielded cable. If not, the ground and signal wire should be twisted together for their full length (use a drill to twist if you don't gave twisted pair wire. Use stranded, not solid wire...

 

[DMPstar]

Curtis also uses an interlock switch at the throttle. So a couple extra wires in that loom.
Pot low in these controllers is not exactly the same as ground as it has fault checking. I would only wire it as shown in the manual.
I am still unclear Remy. Are you saying to twist, shield, and then run shield to chassis?
That should be good.
Curtis 1238 used battery negative for LV reference on many models. Worth noting.

 

[remy_martian]

Ideally twist shield, connect shield to chassis.

In the absence of a shielded cable, tight twist potbox negative and signal for the run, do not ground potbox negative to chassis.

 

[Stephan]

Ideally twist shield, connect shield to chassis.

In the absence of a shielded cable, tight twist potbox negative and signal for the run, do not ground potbox negative to chassis.

Ideally twist shield, connect shield to chassis.

In the absence of a shielded cable, tight twist potbox negative and signal for the run, do not ground potbox negative to chassis.

If shielding is the main problem then I will have to pull this loom apart again and rewire my PB-6 connection. These wires are certainly not twisted. I added already my own version of shielded cable to the extension part. This is 1/3 of the total length, about two foot. I shielded all 4 wires by pulling apart a coax cable. Coax is nice and easy re-usable shielding material (just from the look/I am totally no expert here..). I did not yet ground this added shield to the chassis. Worth mentioning is that not only I extended the Curtis wiring loom, but also redirected it and now going in front of my Leaf battery modules, close and parallel with my HV B+ cable. It is also much closer distance (20cm) from the AC50 motor itself and very close to DCDC. It used to be via the backside of Leaf batteries and mostly crossing other cables.

So, I have a few reasons to think that interference is a problem, and more reason to twist and shield.

My connections PB-6 to 1238 Curtis;
pin 25 - 12v Red wire
pin 18 - (0-5v) pot low - Purple white wire (signal wire not yet twisted)
pin 16 - (0-5v) pot wiper - yellow white wire (signal wire not yet twisted)
pin 9 - (is this same as 'potbox negative'?) pedal interlock - green wire <-- is this also recommended to twist?

 

[DMPstar]

pin 9 - (is this same as 'potbox negative'?) pedal interlock - green wire <-- is this also recommended to twist?

This is a switch signal to show the controller that the throttle is applied, 12v on or off. Should not need special attention like twisting.
Remy''s suggestions of ensuring the pot wiper and pot low are twisted together is because the signal of pot wiper is 0-5v, more susceptible to noise. Suggestions are based on his many years of system designs and are scientifically best practice, but if it means rewiring your whole loom at the moment, let's try some other things first.

I did not yet ground this added shield to the chassis

Shield with no ground connection will not do anything, in case you were unaware.

You have PC Programming station on a laptop? I would next try some of your stationary motor spin tests on the driveway while: -monitor - inputs - throttle -
In here you can look at the raw throttle voltage as received back into the controller as well as mapped throttle command in nice little sliding visuals. Any time throttle issues have been causing faults for me, it was immediately obvious by watching here.
Do test both stationary, then slow up and down on driveway, and then with park brake or foot brake on a bit to pull more current.

Yes, stay off the roads for now

 

[Stephan]

So it seems to happen when in motion.

The problem is not only in motion. Today, another day rain pouring down. our whole state is underwater.. , I did a quick basic test to the start motor, turned key switch, while sitting dry in the car, and bummer, standing still in very extreme wet day, it gave me the error 41 again. "Throttle wiper high". Note that earlier when I ran for the first time in the 41 error, I did measure with the wires disconnected from the PB-6, on pin 16; I measured around 15-20v - so much higher than 5v. I did this measurement on my multi-meter by taking the negative from spyglass and pin 16. The problem since, it was back to normal and I could not reproduce it for some time; I thought it was resolved by rewiring and my failed attempt to shield it. So now, I guess your programming software monitoring will be useful;
I plan to try soon with my 1314 Programming Station software. I never tried it and keen to learn what I can see with -monitor - inputs - throttle. It may take a few days or even weeks longer before I can work on it, due to circumstances. For now, thanks so much for the great expert advise! I will post soon again.

 

[DMPstar]

I did measure with the wires disconnected from the PB-6, on pin 16; I measured around 15-20v - so much higher than 5v.

That is the wiper return signal to the controller, so I don't know what should be expected for a floating voltage when potbox disconnected from the controller.

Stay dry, lots of weird weather all over the place right now.

 

[Stephan]

Progress: today I captured first time data from Curtis in action; monitor - inputs - throttle. It stopped raining and great blue sky. With this quick test and all seems normal. The car did move a few meters a few times, did not break down.. yet.

LOG Start: Date: 12/03/2022 Time: 5:27:40 PM -Curtis monitor data & my Batrium stats FILE attached

Time	Inputs | Mapped Throttle	Inputs | Throttle Pot	Battery | Keyswitch Voltage	Battery | Battery Current	Battery | Battery Power	Motor | Motor RPM	Motor | Temperature	Controller | Current (RMS)	Controller | Temperature	Controller | Regen	Vehicle | Vehicle Speed
45:46.0​	11.6​	0.85​	95.8​	7.8​	0.5​	247​	27​	82.6​	31​	Off	1.2​
45:49.3​	11.4​	0.84​	95.8​	5.8​	0.3​	233​	27​	77.4​	31​	Off	0.9​
45:49.6​	11.4​	0.84​	95.8​	8​	0.5​	291​	27​	82.1​	31​	Off	1.4​
45:50.2​	11.3​	0.84​	95.6​	10.5​	0.8​	500​	27​	81.7​	32​	Off	2.6​
45:58.8​	0​	0.31​	95.9​	0​	0.1​	484​	27​	3.4​	32​	On	1.9​
44:59.2​	0​	0.23​	95.8​	0​	0​	0​	27​	3.1​	31​	On	0​

Next time,

• I will continue with tests up and down on my driveway. Keep measuring until it breaks down again. I hope the outcome is that the monitoring data will tell me what the problem is if it still is there.
• Test if shielding of loom will change the measured throttle data
• Inspection of all contacts on the Curtis in wet conditions, inspect for damp rust etc

 

[Stephan]

Update: 7 days later. Today the controller failed again due to uncontrolled high rev. No rain and dry weather this time. The cables to the controller for this test are tight to the other side further away from motor and DCDC. For a few minutes I drove about 2 meters, sometimes with the handbrake on to draw more current and test the torque. It took only 2 minutes before the high rev started. When I pushed harder about 60% on throttle with handbrake on, the problem started. At around 2 minutes t the max current (RMS) I measured on the controller was 349 amp. And the max rpm was close to 3000.
I forgot to start the curtis programming station logging. I recorded on my laptop screen hence attached screen shot at 12 sec with highest Amp, and on 39 sec with highest RPM. At 40 seconds the controller lost communication.

• I start to doubt if this was a throttle problem.
• I can't recall what happened first. Either I turned off the car or at around 3000 rpm, or it turned off by itself for unknown reason.
• Looking back at the screen I am keen to learn about the difference between Controller current RMS versus Battery Current, as there was a large lag after the max 349 and some current draw of 50-100amp from battery.
• Also, does re-gen breaking settings play a role? The motor in free gear should not re-gen and I currently have no switch on this. I actually just noticed that re-gen appears to be turned on and to exclude this from being a problem I would like to turn re-gen off for the time being to not complicate things.

Not sure yet what to test next. Maybe I try and repeat the same a few times. Preferable without re-gen.

 

[DMPstar]

Stephan,
I finally have a Curtis 1238 drive system set up on the bench so I can confirm some settings etc. over the next few days.

Disclaimer: Depending on your software or level of access to the controller, there may be parameters described that you don't find.

I forgot to start the curtis programming station logging.

From the logging table a couple posts back I see a gap of around 8 seconds between two of the lines, is this normal logging output? I have not used your version of the software or logging on this device and usually just watch the live outputs. Logging cant hurt, but if there are big time gaps between data points you may miss crucial parts of the event as they can happen quickly.

I can't recall what happened first. Either I turned off the car or at around 3000 rpm, or it turned off by itself for unknown reason.

Take a pic or write down your fault history. Then clear fault history
Now follow this process when diagnosing issues with your controller:

1-Keyswitch on, check for no fault blinks or active faults after startup and main contactor closing.
2-Do whatever test you are doing, monitoring, whatever. Take your time, observe. You are still on your driveway.
3-If you experience anything that seemingly registers a fault and/or opens the main contactor, don't turn off keyswitch. Record active faults and fault history, then clear fault history. Turn off keyswitch.
4-Goto 1 for next test.
Only change one variable (rewiring, reconnecting, moving harnesses around, cleaning/lubing, changing parameter) if possible for each test.
Obviously if you are worried about motor runaway damage to drivetrain you can turn off the key in an emergency.

What is the fastest the motor RPMs have gone during a runaway test? What is the fastest they can go on a good test? Do either of these correspond with the programmed max motor RPM settings? (possibly found in several places under varying names depending on your controller software). Do any of those test speeds correspond with ANY settings in the program tree that contain the letters "LOS" (limited operating strategy)?

I start to doubt if this was a throttle problem.

Maybe not, but you have been getting throttle faults. Could be that multiple small problems exist further complicating our efforts. Cars that have long naps don't wake up easy, trust me.
Have you removed the BMS relay from throttle line(s)? Have all connectors related to the throttle and encoder circuit been inspected/cleaned/inspected?
If you find the value --Program - Throttle - HPD/SRO Type - - if it is not set to 2, do so. Ensure the parameter change is sent and sticks. Main contactor may open. Cycle key. Write down every change you make and switch them back after your next set of tests.

Looking back at the screen I am keen to learn about the difference between Controller current RMS versus Battery Current, as there was a large lag after the max 349 and some current draw of 50-100amp from battery.

Battery current - The present DC current at battery voltage, pretty close to what BMS should read if you don't have any other battery loads on. Can change very quickly, faster than the monitoring output can display. Negative values should be Regen current.

Controller/motor current- The AC current to the motor, at whatever AC voltage and switching frequency is happening at that split second. Speed/load/switching voltage dependent, more complicated. Also happening faster than can be displayed. I use this more as reverence for diagnosing shuddering slow/stopped motor syndrome or encoder issues.

Any live or PC logged values are subject to delays from communication speed restrictions.

Also, does re-gen breaking settings play a role? The motor in free gear should not re-gen and I currently have no switch on this. I actually just noticed that re-gen appears to be turned on and to exclude this from being a problem I would like to turn re-gen off for the time being to not complicate things.

Mashed up settings in any place can play a role, turning off regen may help narrow it down. One thing at a time though and try to get the problem to repeat.
I spun my motor on the bench and saw small negative current blips when letting off throttle due to inertia, your flywheel is capable of the same.

At 40 seconds the controller lost communication.

Is this normal? Does the dongle lose its comm lights and your computer disconnect during a fault? Please explain a bit of this.

 

[cricketo]

Long thread, but just in case this hasn't been mentioned yet - Curtis requires that pot isn't tied to the ground. So like if it's a 3-wire resistive throttle, none of the 3 pins will be tied to either battery positive or negative.

 

[Stephan]

From the logging table a couple posts back I see a gap of around 8 seconds between two of the lines

The print above was with ordering applied, the logging is around 2x per second. See PDF print attached (12/3 Test low throttle). Thanks for your detailed reply. I will look into it a bit later. Cheers