Motor cuts out as approach full throttle

P

PRW

100 kW
Joined
Nov 10, 2011
Messages
1,046
Location
Melbourne, Australia
I never saw it draw more than 150 something watts, which would be less than 3 amps. Never saw voltage sag,
 
Ahhh I didn't see the video where it's just spinning no load. That's weird that it would cut out just doing that. The CA stays on so I'm guessing it's not the BMS
 
If you have one available to you, testing another battery would be a great step toward the process of elimination. Testing your battery on another bike would also help narrow it down. It almost looks like the controller is hitting some kind of limit, maybe thermal? Did this setup work fine before it started giving you trouble?
 
It's kind of a long story...
originally I had a Hyena geared hub kit (motor and controller) with a 59.8v LiFePo4 battery. The bike sat around in Australia for 18 months.

When I got the bike back, somehow my son had destroyed the hub bearings; I replaced these, but in doing so, twisted and cut the motor wires. Bought a new mac 10t, installed, couldn't get to work. Seemed to have battery and controller issues - a friendly guy on ES (quuxman) managed to get things working for a while with a new controller, then had issues where nothing would switch on or work again. LiFePo4 battery was a concern - so I bought a new battery (the Luna mini) to test.

I was very pleased to get it all running again - but still have a problem!

I have a 48v battery I could use to see if there is any difference - would just need to change out connectors.
 
wesnewell said:
I never saw it draw more than 150 something watts, which would be less than 3 amps. Never saw voltage sag,
Click to expand...

The video showed 185 watts right when the motor stopped, but I agree with Wes. There was no sag on the display, and current was still less than 4 amps, well within what they advertise on the mini cubes.

PRW didn't say what happens next. What has to be done to get the throttle to work again? Shut off controller? Unplug battery?
 
docw009 said:
wesnewell said:
I never saw it draw more than 150 something watts, which would be less than 3 amps. Never saw voltage sag,
Click to expand...

The video showed 185 watts right when the motor stopped, but I agree with Wes. There was no sag on the display, and current was still less than 4 amps, well within what they advertise on the mini cubes.

PRW didn't say what happens next. What has to be done to get the throttle to work again? Shut off controller? Unplug battery?
Click to expand...
good point - throttle still works if I just close and re-open it! No need to do anything else...

[youtube]b1OX2RcRIE8[/youtube]
 
Looks like cut off at 56.4 every time. Unless someone has better suggestion, I say try bypassing the CA? Hook throttle straight to controller.
 
drew12345 said:
Looks like cut off at 56.4 every time. Unless someone has better suggestion, I say try bypassing the CA? Hook throttle straight to controller.
Click to expand...
thanks drew12345 - I will try this tomorrow!
 
A quick knee-jerk 30 second analysis:
  1. Since the CA is still powered up when the motor cuts out - we know it's not the battery hitting BMS LVC
    (Also could look at controller LED...)
  2. From the CA Diagnostics Screen we can see the operator throttle sweeping from 0.88V to 4.26V - so the operator throttle is working fine.
  3. Because of the following - the CA appears to be working properly.
    • From the CA Diagnostics Screen we can see there are no Limit Flags - in particular the LVC 'V' flag - so the CA is not intentionally attempting to limit motor power.
    • From the CA Diagnostics Screen we can see the CA Throttle OUT signal sweeping from 0.90V to 3.60V - so the the CA is generating a consistent throttle voltage to drive the controller that is in keeping with the specified controller 1.0V to 3.6V input voltage range according to the controller manual.
  4. From the CA Diagnostics Screen we can see the current drop to zero (motor cuts out) at about 2.55V to the controller which is a little over half throttle. Since the CA is properly applying throttle to the controller, the controller appears to be at fault and deserves further attention.
So -
  • Is the controller blinking error codes?
    Not too helpful for this controller in general, but always worth a look:

    LED-codes.png
  • Perhaps the halls are mapped incorrectly (switched phase wires, etc resulting in a false positive combination that just appears to work). Unplug the halls and repeat your test running in sensorless mode.
    If this works - problem identified - in any case you will need to do the hall-mapping procedure in the manual once you've run sensorless.
    If it doesn't help, contact Grin Tech Support.

Also - thoughts unrelated to your present issue:
  • The empty SOC icon on the CA is an indication that you are likely using the original battery configuration for the LiFePo4 pack. Beyond the inoperative SOC indicator, the LVC is likely inappropriate. If you change batteries, you need to tell the CA.
    • Enter Setup and configure a second battery.
    • Select the second 'B' battery.
    • Select LiMn for the chemistry, the number of cells to 14, and the LVC to about 14 * 3.5V = 49V.
  • Your Throttle OUT voltage looks marginal. Obviously with the cutout problem you can't follow the setup procedure in the CA Guide but working from the specification of controller input = 1.0V-3.6V, I would recommend settings of 0.9V-3.7V to ensure the controller turns off at ZERO throttle and actually achieves full power at WOT. The source of the present settings seems unclear and perhaps the full CA installation procedure was followed, but it looks like it might be a good idea to revisit it. In any case, plugging in numbers from a spec sheet is a suboptimal solution so relying on the 0.9V-3.7V recommendation is a guesstimate and not the proper way to tune a CA3.
 
Nelson37 said:
So, it used to work, then your son beat the bejeezus out of it, and it did not work. Replaced motor, still did not work. Replaced controller, worked for 5 minutes, or 5 days, or 5 weeks, etc, then it stopped working. (Use of standard time measurements instead of terms like "a while" can be helpful). Then you got new battery, and have weird throttle issue. Was anything else replaced, changed, or altered during this time?

Throttle, CA, what else is still there from original breakage? These would be suspect parts. New parts that have been connected to suspect parts, also part of a system that stopped working, should also be considered suspect.

When troubleshooting a complex system, eliminate everything you possibly can. I would remove the CA, test with another throttle, or PAS, also original battery if still functional.
Click to expand...
yip, that's it. When the controller was replaced, the bike worked for about 30 miles, over 2 days - then stopped working. This was with the original LiFePo4 battery, but (according to quuxman) some of the cells had gone bad, he wasn't happy working on the bike anymore because he didn't trust the battery. The throttle was the same throttle at all stages - but now, with the new controller and battery, shuts off at higher speed.

I will try connecting the throttle directly to the controller, as well as getting another throttle (will have to order).
 
Nelson37 said:
You mention that the throttle, with a new controller and a new battery, shut off AT A HIGHER SPEED??? Did it shut off, in similar fashion, at a LOWER speed, with the old controller, original problem, and/or with the replacement controller?
Click to expand...
when the bike worked, originally 18 months ago before the motor was replaced, and for the 30 miles (for 2 days) after the controller was replaced, there was no issue with the throttle.

Nelson37 said:
Has the failure mode been essentially the same in all three failures, meaning it works with minimal throttle then somewhere short of full throttle it just turns off?
Changing the controller and/or battery just affected the speed at which it turned off? This would seem to me to indicate some sort of "dead spot" on the throttle. Do you have a 3-speed switch by any chance? If the three positions give the same result at roughly the same throttle rotation, IMO there's your answer.

Or did it "stop working" in some different way?
Click to expand...

there was originally a 3 speed switch - which I have now taken off. This was not used (was not connected) when the bike worked for the 2 days
 
teklektik said:
A quick knee-jerk 30 second analysis:
  1. Since the CA is still powered up when the motor cuts out - we know it's not the battery hitting BMS LVC
    (Also could look at controller LED...)
  2. From the CA Diagnostics Screen we can see the operator throttle sweeping from 0.88V to 4.26V - so the operator throttle is working fine.
  3. Because of the following - the CA appears to be working properly.
    • From the CA Diagnostics Screen we can see there are no Limit Flags - in particular the LVC 'V' flag - so the CA is not intentionally attempting to limit motor power.
    • From the CA Diagnostics Screen we can see the CA Throttle OUT signal sweeping from 0.90V to 3.60V - so the the CA is generating a consistent throttle voltage to drive the controller that is in keeping with the specified controller 1.0V to 3.6V input voltage range according to the controller manual.
  4. From the CA Diagnostics Screen we can see the current drop to zero (motor cuts out) at about 2.55V to the controller which is a little over half throttle. Since the CA is properly applying throttle to the controller, the controller appears to be at fault and deserves further attention.
So -
  • Is the controller blinking error codes?
    Not too helpful for this controller in general, but always worth a look:

    LED-codes.png
  • Perhaps the halls are mapped incorrectly (switched phase wires, etc resulting in a false positive combination that just appears to work). Unplug the halls and repeat your test running in sensorless mode.
    If this works - problem identified - in any case you will need to do the hall-mapping procedure in the manual once you've run sensorless.
    If it doesn't help, contact Grin Tech Support.

Also - thoughts unrelated to your present issue:
  • The empty SOC icon on the CA is an indication that you are likely using the original battery configuration for the LiFePo4 pack. Beyond the inoperative SOC indicator, the LVC is likely inappropriate. If you change batteries, you need to tell the CA.
    • Enter Setup and configure a second battery.
    • Select the second 'B' battery.
    • Select LiMn for the chemistry, the number of cells to 14, and the LVC to about 14 * 3.5V = 49V.
  • Your Throttle OUT voltage looks marginal. Obviously with the cutout problem you can't follow the setup procedure in the CA Guide but working from the specification of controller input = 1.0V-3.6V, I would recommend settings of 0.9V-3.7V to ensure the controller turns off at ZERO throttle and actually achieves full power at WOT. The source of the present settings seems unclear and perhaps the full CA installation procedure was followed, but it looks like it might be a good idea to revisit it. In any case, plugging in numbers from a spec sheet is a suboptimal solution so relying on the 0.9V-3.7V recommendation is a guesstimate and not the proper way to tune a CA3.
Click to expand...
ok, a possible clue - controller light blinks 4 times = "motor has stalled"
 
drew12345 said:
Looks like cut off at 56.4 every time. Unless someone has better suggestion, I say try bypassing the CA? Hook throttle straight to controller.
Click to expand...
I plugged the throttle direct into the controller - motor did not turn at all;
 
Thanks Nelson37 - prior to installing the current battery and controller, when the bike worked, there was no dead spot in the throttle at all. I have ordered a couple of new throttles from Grin, hopefully they arrive before the weekend.
Cheers
Peter
 
update on this - the new throttle makes no difference, motor still cuts out at around 3/4 throttle. I am going to play with the speed throttle settings, and see if that makes any difference.
 
Based on the previous posts, I am not entirely certain of exactly what has been done, and in what order things happened / changed.

It sounds like controller was changed *before* problem started?

If so, and it is not identical controller (or is not identically programmed), perhaps it's eRPM limit is lower than that of the original controller, and so when the motor reaches the higher RPMs the controller can no longer keep up. (this can sometimes happen with geared motors and certain controllers).



Another possibility is that the throttle outputs a higher voltage at full throttle than your controller is designed or programmed to support (or the controller is defective). Often this is marked on the controller, so you can measure the actual throttle output voltage at it's signal wire while it is hooked up to the controller, and see what it's actual output range is.
 
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