Kraton Max 5 Thermal cut off

[needbout350]

Hey all I just set up a new Kraton 8s exb with max5 esc and hobbystar 980kv geared 29/39 and the esc keeps hitting thermal cut off. It’s set to 125c/257f and when I check the temperature the esc has never been hotter than 130 and the motor is about 160f. I went through the entire drive train no issues found. I tried a dozen mesh settings for the pinion and spur. I tried bigger and smaller pinions and still no change every run ends with thermal cut off. Driving mostly on pavement and outside temp has been 65-85 when testing and driving with mixed throttle. I’m using EC5 connectors with 8000mah batteries. GPS shows top speed of about 55mph. I’ve got 1mill front diff and 500k in the rear the center is the stock 20mil.

A buddy of mine has the exact same setup with 32/39 gears and has no issues. I’ve heard of many people gearing way higher that 29/39 without problems. What am I doing wrong?

 

[jkflow]

What is your BEC set at? Work wonders on fan speed and cooling. You should run on 7,4V, assuming your servo can handle it.

Taking the external tempo is very misleading. All ESC have internal sensors. My Firma ESC is external at 140F and internal crosses the 200F line.
Check the ESC fan for any obstruction, I suggest upgrading the fan as well.

 

[needbout350]

What is your BEC set at? Work wonders on fan speed and cooling. You should run on 7,4V, assuming your servo can handle it.

Taking the external tempo is very misleading. All ESC have internal sensors. My Firma ESC is external at 140F and internal crosses the 200F line.
Check the ESC fan for any obstruction, I suggest upgrading the fan as well.

I have an old flysky fsit4 remote so all the receivers I have max out at 6v. 7.4v will fry them. I am using a 65kg power hd servo it’s rated for 6.0-8.4v. I’m sure it’s pulling a lot of amps on 6v. Maybe that is the issue might be time to upgrade the remote and receiver.

What fan do you recommend?

Getting a bit annoyed with the rig since the rtr is rated for 55mph and this setup isn’t any faster for almost 500 dollars more. I’m getting a fan for the motor to run bigger pinions for more speed but it won’t matter if the esc cuts out halfway through a battery every time.

 

[jkflow]

I stopped using Max6 for the same reason. You would need a fan adapter and a 40mm high speed fan but if you run this on 6V you won't see a big improvement.

 

[KevinC]

Just to be sure……what colour is the flashing light on the ESC? Are you sure it’s not LVC?

cheers,
kev

 

[needbout350]

Just to be sure……what colour is the flashing light on the ESC? Are you sure it’s not LVC?

cheers,
kev

It flashes green. Per the manual that is thermal cut off. I double checked to be sure. Also the 8000mah batteries show 30% and the most I have had to recharge that was 5500mah.

I think there might be something to the fan speed. I took it for a bash session at a local club and managed to run it through a whole pack. It was on a tighter dirt course so I didn’t have as many wot passes and it stayed cooler. I hit LVC (red light) and the packs took 8050mah. My budy is running with an NB4 and is using 7.4v bec setting it’s the only difference between our rigs.

 

[needbout350]

I’ve got a new radio with a high voltage receiver on the way but it won’t be here until the end of the month. I’ll flog it in the street once I get it set up and report back to let you know if that fixes my issue.