ARRMA Limitless overheating problems

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bendunmore

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Arrma RC's
  1. Limitless
Would anyone have any ideas on cooling for my arrma limitless as it keeps over heating on the ESC? I'm currently running the hobbywing max 8 system with 3s batteries and two upgraded fans for the motor/ESC.
 

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Would anyone have any ideas on cooling for my arrma limitless as it keeps over heating on the ESC? I'm currently running the hobbywing max 8 system with 3s batteries and two upgraded fans for the motor/ESC.
What motor and gearing?
 
I’m running the EZRUN 4268 (2600kv) and gearing is Pinion 27T - 34T Spur.
 
Yeah man, that is way too little motor in that car even with normal gearing. You’re going to need a 4074 at the absolute minimum but it’s recommended you jump to a 4082 and higher if you want to run super high gears. The issue with that is the max8 gets hot in applications like this because they’re not really ideal for speed running vehicles.
 
Thank you both for your replies. That has been very helpful. What would you suggest would be a better system to use and what gearing? Or would it be okay just to change the motor to 4082 or better?
 
I’ll look into purchasing these when they are back in stock. Thanks for your help!
 
You should watch your gearing. drop it down a notch. Shorten all your lipo wires a bit to help the ESC be more efficient. Long wires create resistance at the ESC. Try a cap pack. Double fans/Heatsink. Yeah Racing 1/8 HS w/Tornado fans. You might be able to bash with that motor. 2600kv seems a bit high for your purposes but can work. Even the stock BLX setup 2050kv will overheat the same. Fans and gearing......
 
Just an update on my progress on my limitless I have now got the max6 with 4895 system with 3s which it working a treat.

So just to be extra safe with cooling, what would be the best cooling fans and bracket for the motor and ESC?
 
Just an update on my progress on my limitless I have now got the max6 with 4895 system with 3s which it working a treat.

So just to be extra safe with cooling, what would be the best cooling fans and bracket for the motor and ESC?
A single 3S?
 
Two 3s battery’s
Makes more sense ??? All that for a single 3S pack would be silly. Mr. Duke made his own fan bracket that looks killer. Not sure what others are doing for that sized can.
 
I find with be it either it ESC, Motor, Cpu or Gpu the best way to tackle heat is kill it at the source adding heatsinks will allow for heat soak and will only prolong the effect it takes reach the temp due to the bigger surface area to heat up, using thin fins will give bigger surface area but once this has taken affect this then needs to be cooled by a source to be effiencent enough to cool the hole unit and keep it within a working temp or it will continue to rise, such as a 30mm fan trying to cool motor or esc with 5cfm with low staic pressure no matter if it 50,000 rpm is not going to poor hit the sorce with high cfm fan with a large staic pressure over a greater surface area witll help.
 
A single 3S?
He must mean 2x 3s.
I find with be it either it ESC, Motor, Cpu or Gpu the best way to tackle heat is kill it at the source adding heatsinks will allow for heat soak and will only prolong the effect it takes reach the temp due to the bigger surface area to heat up, using thin fins will give bigger surface area but once this has taken affect this then needs to be cooled by a source to be effiencent enough to cool the hole unit and keep it within a working temp or it will continue to rise, such as a 30mm fan trying to cool motor or esc with 5cfm with low staic pressure no matter if it 50,000 rpm is not going to poor hit the sorce with high cfm fan with a large staic pressure over a greater surface area witll help.
Reading between the lines...makes sense... in theory.
That's why Higher CFM's blowing onto a bare motor Can is best if you cant control heat enough using a HS. Heat soak rises at a faster rate than it dissapates. Cool down periods are important. But in the end, a proper motor/gearing setup shouldn't require much attention if done properly. :cool:
Edit: Killing heat at the source is key, yes. In my example, I found that most heat is generated at the Phase wire end of the motor's Can to be the source. (inductive resistance occurs here) It is generated at this end. I use a temp gun. A 20x20mm heatsink at this end using thermal epoxy works perfectly, measurably cooler. This reduces heat soak at the motor Can's center.
Take temp readings very closely, and you will find temps to be higher at this end. A very hot motor causes loss of brakes (hot magnets).
It also creates more resistance at the ESC. Warm/hot wires is a sign of this.
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