Hi all I've bought a second hand car (T4) with a hobbywing v3.1 esc running a nosram motor and MaxAmps 6500mah 2s 150c lipo now the car has been totally pulled down and gone over with all bearings replaced etc etc and the wiring from the esc to the motor was shortened as it was long enough to loop the car twice , this is the first electric car we've owned and I haven't done much soldering before but everything seems ok apart from the fact that the esc seems to run a little hot after a few minutes of test driving up and down say a 20 metre distance and then it cuts out like it is not receiving any signal from the radio. The radio is a ko prop ex1 v2 and the lipo in the car is fully charged, the battery reading on my radio is 5.0v and the fan only seems to switch on for a second when I switch the esc on and then shuts down and I haven't noticed it switching on again, the program box is telling me the esc reached 92c after literally 2min of use and the car was shutting down or not receiving any signal from the remote and the esc lights were flicking on and off then it would after a couple minutes of sitting all of a sudden wake up and respond again any ideas? Is it running hot or is this normal and what could be causing the esc to cutout like it's doing ?
Thanks

Sounds like the ESC is overheating and shutting off to protect its self. Once it cools off it turns back on. On the v3.1 the fan should be on all the time if it is plugged in. Even when the fan is unplugged it shouldn't overheat in 2 mins.

What turn motor are you using?

There are a couple typical causes for this. You could be way over geared or under geared. Over gearing will usually overheat the motor first. Under gearing will usually overheat the esc.

You could have your pinion gear to spur mesh to tight. That will cause a lot of resistance in the drive train and over heat things really fast. There could also be some binding in the drive train that is causing a lot of rolling resistance.

While poor soldering could cause overheating at the solder joint I doubt it is what is causing your thermal overheating issue.

Make sure the fan is plugged in all the way. If it starts and then stops give it a little push and see if that gets it going.

Something is causing your overheating issue. Its hard to say exactly but it is most likely a resistance issue. Check the pinion/spur gear mesh. If you just replaced the bearings that would be my first guess. Also the motor should turn fairly freely when not connected. If it doesnt there could be a bad bearing or rotor in the motor.

The fan should be running constantly on the v3.1. I bet your fan is "toast". Head over to the Hobbywing thread in the "off-road electric" section if you need more info.

The motor is a 5T nosram unit and it does not even get warm, the fan is cooked as I gave the wire a gentle shake and spun the fan and it started spinning turned the esc off and on again and wasn't working again so I'll replace that. As far as binding goes I can't see any issues I will double check everything but it all seems ok. I'll double check the gearing and let you know what it's at also the motor does turn really smooth when it's out of the car. I'm hoping the fan will help keep temperatures with in limits but I'll post the gearing that's in the car and maybe you guys can let me know if it's off or not
Thanks

Also remember the rules of gearing. See attachment.

Motor pinion is 28 spur gear is 78 is there anything else I need to look for and add?

It seems that is waaaayyyy overgeared. You said T4 so I'm assuming an associated t4. They don't even have a recommendation for a 5T motor. Screenshot from the manual below. Your motor looks to be a 6900kv motor according to the Nosram site.

No sorry xray t4 should've been a bit more clear about that

Do you have a link to the nosram site charts, I can't seem to find it

i have been getting the exact same results for my TRAXXAS VXL ESC and the only problems i have had are over heating (as in hot enough to melt down solder) and then a ESC at the temp at 120* F after about 5 mins of run time. I'm just gonna upgrade to Castle sidewinder 3

An ESC gets hot when it is pulling a lot of amps. In stock racing, on-road, we don’t even run a fan! However, a 5T motor is pretty hot and near the limit for that esc. If your gear mesh is even a little tight, you can draw a lot of extra current quickly. So, make sure that you can wiggle the spur back and forth while holding the pinion and feel a little ‘click’. If you can’t feel that click, your mesh is too tight.

I also run an Xray T4. With the pinion off, spin the front wheels quickly. They should continue to spin for a second. If they don’t you have binding issues in the drive train. Make sure the belts aren’t too tight and that the eccentric bearing holders are set the same side to side so that the spool and diff are aligned with the belts.

After that, make sure that you have a working fan. For gearing, whatever you start out at, check temps after a minute, if everything looks good, go for another minute or two. If you can get to 5 minutes and stay under 140 degrees Fahrenheit, you gearing should be OK. With a 5 turn motor, there is really very little need to over gear! That will be a rocket.

120°F after 5 minutes doesn't sound hot to me at all. What solder melted? On the ESC or on the motor? The latter happened to me in the past, when I wanted to use bullet connectors on my motor (in order to be able to switch between running mod or stock 4WD buggy without having a soldering iron ready. Didn't work, the connectors got to hot and de-soldered themselves. (BTW, several people tried, also with better soldering skills than mine - same result.) Once I gave up on this idea and soldered the cables directly to the motor, everything worked fine thereafter.

Watch the posting dates .Everything except the post right before yours, is from 2015, including the references to a 5T motor (which was run with an FDR of 1:5.3 - not quite what I would use on a 5T motor. Touring cars in modified class usually run around the 1:7-8ish range. However, a gearing like this should leave the motor smoking hot...).Settings like PWM and use of brakes, etc. can heat up ESCs as well. Or they can simply fail, like any other device.