Basic ESC Running Hot

Just purchased a T100, Basic ESC and the HiTech 646 Servo. I wanted to run a battery duration test on a MultiStar 14.8v, 4000mAh LiPO battery. I’m controlling with an Arduino Uno and running a simple sweep program with the T100 running speed up and down during the sweep. I’m running the T100 at the low end (1550 to 1650 ms). I noticed the ESC was getting very warm and gets hotter as I increase the speed. Not too hot to touch, but uncomfortable. I’m concerned if I have four of these units inside a closed area with not a lot of breathing room.

Is this normal for the ESC to get hot?

Hi Terry,

If the ESC is getting hot without running at full throttle then I would suspect the 5V regulator. The regulator on the Basic ESC can only handle 500 mA and it will get hot quickly if you draw much power from it. Are you powering the Arduino and servo through the 5V line on the ESC? If so, I’d recommend using a separate BEC for the servo.

Regardless, the ESCs will get warm in an enclosure. We’ve been using 6 of them side-by-side in our BlueROV and they get warm, but not uncomfortably warm after 30-45 minutes of running.




Actually I’m not using the ESC 5V line at all, just signal and ground. I’m running the servo off a separate YEP SBEC but connected to the same battery, and the arduino is running off the USB to my computer.

The ESC gets hot after a few minutes but does not get hotter the longer it runs (up to 1.5 hrs). I can put a thermometer on it if I new what range is normal. I just want to make sure I don’t damage my T100.


What is the chip number for your 5 volts regulator? Just curious to see if it is a regular one or a LDO variant.



I’m not sure what chip is on the Basic ESC. I’ll take a look when I can. It’s definitely a LDO.


Okay. The heat is probably the combination of the 5v regulator for the micro controller and the mosfets. I wouldn’t worry about it if heat isn’t increasing over time. Our get warm to the touch regularly without affecting function.



Hum … the LDO variants usually run a lot cooler.

As for the heat, one thing you could do is to use something like this material:
Aavid, Thermal Division of Boyd Corporation and on the other side of the gap filler use metal or something to conduct the heat to your housing (unless it is plastic and you might as well just call that an insulator) and let the surrounding water cool the system. The other thing is the gap filler itself can just act like a non-conductive heat sink so you don’t have to worry about shorting stuff out.

Heat is going to be a major issue in your battery packs too! I have used LiPo’s in projects near space (20 miles up) and you would think that with the temperature being 80 F below zero that heat wouldn’t be a problem … wrong answer! We had to let our package cool down for 45 minutes after we retrieved it and that was hours after it came back to the ground.

Conducting heat away from your producers is going to be an issue for the electronics and anything else in the ROV.


Thanks for the help guys. I’ll keep an eye on it.

BTW, the chip number is LM2940L. Datasheet says its an LDO.