Viper RC -
I've got a VTX10 and a viper 7.5 motor I'm running in a stadium truck. I keep having issues with it shutting down (except for steering) and then eventually taking back off while racing. Happened with different batteries, including new ones. Temps don't seem to be too high. Ran qualifiers the other night with no issue but it cut out twice during Main.
It's done this since it was new. I quit running it for quite a while and the class picked back up and issues has now returned. I'm pretty sure I have temp limits raised just to make sure that wasn't the issue. I will check settings tonight and reply back. There are a lot of settings, which ones would be main ones to document what they are?
Joined: Nov 2003
Posts: 3,595
From: Covington, La.
One way you can rule out the thermal cutoff is if it only happens after the car is being run for several minutes. However, if it is happening at random times it has to be a short somewhere. Wither it be in the battery terminals, motor wires or the sensor wire/ sensor board in the motor.
One way you can rule out the thermal cutoff is if it only happens after the car is being run for several minutes. However, if it is happening at random times it has to be a short somewhere. Wither it be in the battery terminals, motor wires or the sensor wire/ sensor board in the motor.
Joined: Nov 2003
Posts: 3,595
From: Covington, La.
If I remembered right, it was disabled. But I was having the issue and enabled it and raised it way up to see if it made a difference. It was late in the main when it stopped both times. I checked temps when it came off track. Don't remember what it was, but it was well under 200.
If it is always late in the run and you can rule out the temp my next thought would be the voltage cutoff. what are your batteries at voltage wise after this happens? Are they always around the same voltage? You may be dipping past the LVC under a heavy load.
While the subject of motor temp protection is being talked about let me clear up a common mistake. The motor temp protection is internal temp. Not external. If you have it set for 200 degrees it may only be 140-150 on the outside. With most motors, if I want the ESC to shut down with an external motor temp of 160, I usually set it around 230. After I figure out my gearing, I turn the temp protection off. To figure out the internal/external differential, set the motor temp protection to 160. Run the car until it shuts off on thermal. Measure the outside on the hottest spot. If you have a 50 degree differential, set your ESC 50 degrees higher than you want your motor to shut down at.
Once I find my correct gearing I don't worry. Plus, at 2 different national events, I lost a qual because I had the motor temp protection set too low. I gear my vehicles to come off the track around 130 max. That way any outside temperature issues keep me safe.
When you had the others serviced, what did viper report back as the problem that was found?
What motors have you run in the past and what vehicle were you using this in?
Been curious about performance of the motor in 4x4 SCT relative to "545" sized motors like the Hobbywing 3656SD I currently run and the 550 Tekin. Not expecting that level of power as it is a 540 but curious how it feels in general, as well as temps since the came is smooth versus other vipers that are ribbed.
What motors have you run in the past and what vehicle were you using this in?
Been curious about performance of the motor in 4x4 SCT relative to "545" sized motors like the Hobbywing 3656SD I currently run and the 550 Tekin. Not expecting that level of power as it is a 540 but curious how it feels in general, as well as temps since the came is smooth versus other vipers that are ribbed.



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