Extreme Bull Commander HS unexplained cutout

[Bookmark]

Hi everyone, first post here.  I experienced cutout riding my Extreme Bull Commander a couple weeks ago.  Less than three miles into my ride, my Extreme Bull Commander (EBC) HS unexpectedly cut out on me.  I was cruising at a steady 19mph on a very smooth sidewalk which was relatively flat and with no potholes or obstacle on the road.  There was no tilt back or beep (why would it since I wasn't going very fast or leaning very hard and top speed of the HS is 50mph).  I was wearing protective gear and didn't break any bones but got some road rash and a lot of aches from falling onto the concrete unexpectedly.

Here are some additional details:

• Battery level read 76% when I fell and went back up to 80% after letting it rest for a few minutes.
• The wheel stayed on the entire time, took barely any damage, and I was able to ride it back home albeit slowly and fearfully.
• Outside temperature was 85F.
• I weigh 182lbs.
• The fastest I've ever been on the wheel is roughly 35mph, but my typical riding speed is 16-20mph.
• I was going straight at a steady pace, not accelerating or braking hard.
• It kind of felt like the wheel just suddenly started braking and happened too fast for me to react.
• I put about 500 miles on the wheel.
• I bought the wheel brand new 8 months ago, so it is not an early beta wheel.
• The wheel has never been wet or in the rain and only had several very low speed drops.
• The top speed that I reached during the ride was roughly 20mph (supported by EUC World logs).
• I've owned a bunch of other wheels prior with thousands of miles of EUC riding experience and this is the first time I've had an EUC accident that I could not understand or explain.

I provided details, pictures and EUC World log data to Begode and they can't tell what is wrong, but they suspect that a battery may have gone bad and suggested that I measure the voltage of each cell. Honestly, this sounds kind of suspect, and I really don't want to mess with the batteries.  

Anyway, just wanted to let folks know and be aware of the risks of riding.  Take care everyone.

 

 

[Paradox]

If you upload the logs here others may be able to see something in the data.

[alcatraz]

Does the wheel power on normally?

If not, check for a blown mosfet. Sometimes you need to take the heatsink off the board to see it.

[alcatraz]

I had a failiure like that on a hot summer day and I suspect it was because the mosfets weren't bolted down properly into the heatsink. The screws can come lose over time. That means that it overheats without indicating a high temp in eucworld. In fact it would show up as unusually low temp, which I had for thousands of km until it gave up. I'm using the same board fixed with everything loctited down. It works fine and the temps are noticeably higher = good. Added two extra fans too.

Edited September 10, 2023 by alcatraz

[goatman]

i wonder if the hall sensor connector is loose

[Bookmark]

Attached is the log data.

Commander EUC data 2023-08-26.csv

[Bookmark]

On 9/9/2023 at 5:51 PM, alcatraz said:

Does the wheel power on normally?

If not, check for a blown mosfet. Sometimes you need to take the heatsink off the board to see it.

Yes, the wheel didn't turn off even after the crash and I was able to ride it home.  It turns on and off normally.

[Bookmark]

On 9/9/2023 at 5:53 PM, alcatraz said:

I had a failiure like that on a hot summer day and I suspect it was because the mosfets weren't bolted down properly into the heatsink. The screws can come lose over time. That means that it overheats without indicating a high temp in eucworld. In fact it would show up as unusually low temp, which I had for thousands of km until it gave up. I'm using the same board fixed with everything loctited down. It works fine and the temps are noticeably higher = good. Added two extra fans too.

Thanks for the suggestion.  It wasn't hot outside and less than three miles into my ride and I was able to ride it home so it doesn't seem to be an overheat condition.  EUC world indicated the temp was 114F.  I'll definitely inspect the mosfet once I open the wheel up later on next weekend.

[alcatraz]

1 hour ago, Bookmark said:

Yes, the wheel didn't turn off even after the crash and I was able to ride it home.  It turns on and off normally.

Then it's for sure something else. I don't believe it's common with Begode/Commander/Veteran wheels, to fail without any signs of damage.

Although it did happen to Marty Backe (youtuber) on his Begode A2.

[alcatraz]

Maybe check for contamination in the control board area.

Check if it's self discharging or taking a charge normally. Multimeter on each pack to see they're equal.

Check for firmware updates (changelog).

Check for weird calibration symptoms (leaning the wheel left/right leads to cutoff at different angles). I believe that happens after calibrating at cold/hot temperatures and saving bad gyro data. No proof though.

Check the battery and motor wires that they're undamaged. Not pinched, stripped, and not getting poked by screws etc. Check for burns along the wires and toasty looking battery/motor wire connectors. (deformed insulation, dark spots, oxidized connectors)

Check that the fan is running over 40C. I installed extra fans in my wheel, but I had a confirmed overheat situation. Who knows though if another component overheated on yours? Heat = bad. 

Another overheat situation is leaving the wheel powered on for a while. Like parked 2h in 30C temps, and then riding, could be bad for it. It's cool enough for the fan not to start but the board is running and components that only have the fan to cool them might overheat when you then start to get going. Another reason for more fans.

Edited September 11, 2023 by alcatraz

[alcatraz]

If you can't find anything wrong, in order to regain any level of confidence in the wheel I'd do a firmware recovery and room temp calibration, then ride slowly geared up, increasing speed incrementally and logging every ride. Monitor the temp and compare it with other riders on the same model wheel. If it's running unusually cool, then that's a red flag.

Edited September 11, 2023 by alcatraz

[Bookmark]

4 hours ago, alcatraz said:

If you can't find anything wrong, in order to regain any level of confidence in the wheel I'd do a firmware recovery and room temp calibration, then ride slowly geared up, increasing speed incrementally and logging every ride. Monitor the temp and compare it with other riders on the same model wheel. If it's running unusually cool, then that's a red flag.

l appreciate the suggestions.  Hopefully it'll be something obvious.

[Punxatawneyjoe]

The voltage and the temp seem to drop off quick 2 times down to 88v at one point, that can't be right . can it? (like something disconnected for a split second)

Unless ofc I'm reading it wrong which is entirely possible. Just figured id look at it though.

[alcatraz]

Looks like a loss of data. Maybe bluetooth went out?

Check your phone's battery optimization settings for that app.

[Bookmark]

4 hours ago, Punxatawneyjoe said:

The voltage and the temp seem to drop off quick 2 times down to 88v at one point, that can't be right . can it? (like something disconnected for a split second)

Unless ofc I'm reading it wrong which is entirely possible. Just figured id look at it though.

 

I've attached the graphs that AR support provided me along with support commentary:

"Based on this, it looks like the voltage remains constant, and the current draw doesn't seem unreasonable, but the wheel seems to slow down on its own (and apply regen braking) during the cutout, then spin up to full speed on the ground before slowing back down as you reported. Later on, you can see the voltage reading drop temporarily as the wheel is picked up/as it restarts. "

[alcatraz]

Gyro data error? Overheating control chip?

[Punxatawneyjoe]

38 minutes ago, Bookmark said:

I've attached the graphs that AR support provided me along with support commentary

Those graphs look very different than the one you provided up above.

the one you posted looks like this:

Edited September 12, 2023 by Punxatawneyjoe

[Bookmark]

7 minutes ago, Punxatawneyjoe said:

Those graphs look very different than the one you provided up above.

AR's graph is for the period near the cutout which was around 10:47am -11:07am.  11:07am is the time I arrived back home and powered off the wheel.  After dressing my wounds, I turned the wheel back on an hour later to confirm the wheel was still working.  That would explain the long ramp down on the graph you gave us. The wheel was off at the time.

I've attached screenshots from EUC world if anyone is curious.

[Bookmark]

Please note the top speed of 62mph was due to wheelspin and not me riding fast.  I topped out at ~20mph on the ride and the screenshots were taken when I got home after the accident.

[Punxatawneyjoe]

7 minutes ago, Bookmark said:

AR's graph is for the period near the cutout which was around 10:47am -11:07am.

right, that's the period i was referring to as well. I know the long gradual line after that means nothing. I was referring to the sudden drop in temp and sudden drop in voltage to 88.7 as indicated on your euc world stats. the graph you showed doesn't have those drops in them. Your ending voltage was 93.7v. Is this better?

i removed speed and a few others so you can see the dips better. I know speed wasn't a factor your average amp draw is like 4.7a so you weren't getting on it much. I don't see it going from 49c to 37c in 30 seconds then back to 47c 30 after that. But you can see how the two graphs still look very different. I don't know, maybe someone smarter than me will chime in.

[Bookmark]

3 minutes ago, Punxatawneyjoe said:

right, that's the period i was referring to as well. I know the long gradual line after that means nothing. I was referring to the sudden drop in temp and sudden drop in voltage to 88.7 as indicated on your euc world stats. the graph you showed doesn't have those drops in them. Your ending voltage was 93.7v. Is this better?

i removed speed and a few others so you can see the dips better. I know speed wasn't a factor your average amp draw is like 4.7a so you weren't getting on it much. I don't see it going from 49c to 37c in 30 seconds then back to 47c 30 after that. But you can see how the two graphs still look very different. I don't know, maybe someone smarter than me will chime in.

Smarter than you and me both, lol.

[Bizra6ot]

Here's the smart guy please step aside 
The AR graph is about 800ms/line vs 200ms on the csv, the lines with the voltage & temp drops don't show up

[Punxatawneyjoe]

3 hours ago, Bizra6ot said:

The AR graph is about 800ms/line vs 200ms on the csv, the lines with the voltage & temp drops don't show up

Ok, so now i have highlighted the area and made the graph closer to the AR graph in ms/line. They show up even more now.

[Bizra6ot]

No I meant that it may not show up on theirs or with lower values because their intervals are 800ms instead of 200ms and it seems to be an instant peak