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HOBBYWING TECH SUPPORT 1/8 & 1/10 OFF ROAD

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HOBBYWING TECH SUPPORT 1/8 & 1/10 OFF ROAD

Old 01-01-2017, 09:04 AM
  #11281  
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Originally Posted by LOW ET
what do you consider reasonable run times? these are race esc's and the race only last between 6-8 minutes. you should be able to run the 6-8min races with the LVC turned completely off with no problems. if you are bashing then i'd start timing yourself.
Very true.....I time my practices with my phone. Whether I am running my mod 4wd buggy or my power hungry Pro4 SC, I set my phone timer between 6-8 minutes. Once Im done, I check voltages once the system has stabilized back in the pits. Both classes are set to 3.0v per cell. Pro4 has the HW XR10 Pro and Mod buggy has the HW 120a V2.1. Voltages vary in both between storage 7.6V and nominal 7.4V. Never have hit LVC in practice or racing.
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Old 01-01-2017, 09:38 AM
  #11282  
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Folks, this is all good. We can help ourselves with clever workarounds however it does not change the fact that FIRMWARE IS BROKEN. Not sure if we have some Hobbywing reps on this forum to provide official statement.
If we start raising this to HW support I believe that sooner or later they will fix it - unless it is caused by some nasty hw design glitch.
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Old 01-01-2017, 01:12 PM
  #11283  
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Originally Posted by astianseb
@gigaplex

This is EXACTLY THE SAME problem i'm observing. To me this is quite apparent bug in a firmware. How you work around it? Manual LVC set? Auto is definitely up to the task. If manual LVC - what would be safe settings for 2S to not over discharge battery and still get reasonable runtime?
I'm not convinced it's a firmware issue, otherwise every single unit would be having issues. I think I set my cutoff to 6.2V and haven't noticed any issue during a race lately.
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Old 01-01-2017, 03:06 PM
  #11284  
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[QUOTE=LOW ET;14785333]it seems your low voltage cutoff is set to high (7V). if im not mistaken average low voltage cutoff is usually set around 3.2V per cell, so if you are running a 2s battery it will be 6.4V. if your low voltage cutoff is set at 7V and the battery dips to 6.9V under load then the esc is doing it's job and shutting down. try lowering the cutoff voltage and see what happens.[/QUOTE

ESC lipo cut off is measured during running/under load. Lipo voltage is 0.3 to 0.5V lower (total), running condition depending on condition of batter, drive train and motor turn. So reading 0.4v higher than cut off voltage on your battery when the car is not running is normal/ esc lipo cut off is working correctly as designed.
Some hobbywing esc have their firmware set too sensitive and triggered low voltage cut off when lipo battery used is going bad or a lower quality. It can be fixed by upgrading to the newer firmware with sensitivity turn down or running lower low voltage cut off setting.
If your goal is to have lipo voltage at 7v/or "X"v under no load condition, set your lipo cut off at ~0.2v or lower than your intended voltage in lipo cut off setting (you need to test it yourself since it varies on your equipment and running condition).
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Old 01-01-2017, 05:26 PM
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Originally Posted by boner
Originally Posted by LOW ET
it seems your low voltage cutoff is set to high (7V). if im not mistaken average low voltage cutoff is usually set around 3.2V per cell, so if you are running a 2s battery it will be 6.4V. if your low voltage cutoff is set at 7V and the battery dips to 6.9V under load then the esc is doing it's job and shutting down. try lowering the cutoff voltage and see what happens.
ESC lipo cut off is measured during running/under load. Lipo voltage is 0.3 to 0.5V lower (total), running condition depending on condition of batter, drive train and motor turn. So reading 0.4v higher than cut off voltage on your battery when the car is not running is normal/ esc lipo cut off is working correctly as designed.
Some hobbywing esc have their firmware set too sensitive and triggered low voltage cut off when lipo battery used is going bad or a lower quality. It can be fixed by upgrading to the newer firmware with sensitivity turn down or running lower low voltage cut off setting.
If your goal is to have lipo voltage at 7v/or "X"v under no load condition, set your lipo cut off at ~0.2v or lower than your intended voltage in lipo cut off setting (you need to test it yourself since it varies on your equipment and running condition).
My one is reading about 0.5V too low under no load conditions. If you assume another 0.5V sag under load, that means I'd need to set the LVC 1V lower than normal.
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Old 01-01-2017, 05:48 PM
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Originally Posted by gigaplex
My one is reading about 0.5V too low under no load conditions. If you assume another 0.5V sag under load, that means I'd need to set the LVC 1V lower than normal.
You have to test it out yourself since it can varies by condition of your battery, motor, drive train efficiency, and temp. Lipo battery have a tendency to "recover" it's voltage. Example, after 5min of racing, my battery normally read 7.4~7.5v right off the track. When I start charging it (after marshaling; 6 to 8 min later) it's reading around 7.6~7.8v before start charging it.

Based on normal racing (5min) you shouldn't be getting closed to lvc (normal HW LVC value; 6.4v) unless you have bad battery, 2000mah battery pack, very low turn motor or something is blinding up on your car.
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Old 01-01-2017, 06:09 PM
  #11287  
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Sounds like your ESC is working fine. I never use the auto setting for LVC, as you found out it's not good. Set it to 6.4V and forget about it. I once made a video showing how much the voltage droops under a load but I don't have it anymore.
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Old 01-01-2017, 06:16 PM
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Originally Posted by boner
You have to test it out yourself since it can varies by condition of your battery, motor, drive train efficiency, and temp. Lipo battery have a tendency to "recover" it's voltage. Example, after 5min of racing, my battery normally read 7.4~7.5v right off the track. When I start charging it (after marshaling; 6 to 8 min later) it's reading around 7.6~7.8v before start charging it.

Based on normal racing (5min) you shouldn't be getting closed to lvc (normal HW LVC value; 6.4v) unless you have bad battery, 2000mah battery pack, very low turn motor or something is blinding up on your car.
As I mentioned in the other thread, my 5500mAh battery was about 7.8-7.9V directly off the track when the ESC read sub-6V. That's with a 21.5T blinky setup on a very free TC3 drivetrain. It would occasionally hit LVC cutoff a few minutes into the race (auto setting). Multimeter readings showed minimal voltage sag under load on the bench, and didn't match the ESC readings from the same bench test. My ESC is definitely not getting accurate voltage readings.
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Old 01-01-2017, 08:04 PM
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Originally Posted by rocketron
Your describing LVC (Low Voltage Cutoff) is set to high for your application.

RED LED on indicates this.
Having same problem with Xerun SCT Pro Sensored mated to Trinity D4 17.5 in my SC10. What should LVC be set at for 2-cell 5.3 Amp 50C lipo?
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Old 01-01-2017, 08:11 PM
  #11290  
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What is the difference between 3652 4300kv and 3660 4300kv? I know one is a bigger can.
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Old 01-01-2017, 08:51 PM
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running on the bench does not simulate on track amp drawn/voltage sag
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Old 01-01-2017, 09:25 PM
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Originally Posted by DJEckart
Having same problem with Xerun SCT Pro Sensored mated to Trinity D4 17.5 in my SC10. What should LVC be set at for 2-cell 5.3 Amp 50C lipo?
I would go for 6.4v or 6.2v depending on what you're comfortable with.
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Old 01-01-2017, 09:28 PM
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Originally Posted by boner
running on the bench does not simulate on track amp drawn/voltage sag
While true, I did say I compared the bench ESC readings against the bench multimeter readings and there was a big discrepancy.
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Old 01-01-2017, 09:36 PM
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Originally Posted by gigaplex
While true, I did say I compared the bench ESC readings against the bench multimeter readings and there was a big discrepancy.
But have you tried forcing a 6.2v or 6.4v cutoff to see if it resolves the issue. It would seem the auto cutoff setting is the issue according to the hobbywing support thread. It's a simple thing to try.
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Old 01-01-2017, 10:09 PM
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Originally Posted by EbbTide
But have you tried forcing a 6.2v or 6.4v cutoff to see if it resolves the issue. It would seem the auto cutoff setting is the issue according to the hobbywing support thread. It's a simple thing to try.
I already mentioned that I tried that as a workaround and it seems to have helped. It's not an incorrect auto cutoff setting, it's an inaccurate voltage reading.
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