Hot ESC, But Apms Are Below Rating?

[squeeforever]

Well it will heat up either way. How hot is it getting?

[jhautz]

Originally Posted by squeeforever

Well it will heat up either way. How hot is it getting?

I didnt have a temp gauge so I don't know exactly how hot. (I went and bought one today). It was hot enough that I could only hold my finger on it for a 5 count and then I had to pull it off. I know that is still probably OK... But barlely and that was after only 3 minutes. Granted, I was running it pretty hard. Full throttle runs across an open grass field.

I know its going to heat up either way, buy it shouldn't overheat if I'm not pushing it to or past its rated constant amp limit. Should it? It didn't thermal, but thats only cuz I stopped running it before it did. Another miute or so and I gaurantee it would have shut down.

I just dont get the whole amp rating thing. If its going to overheat and thermal at a much lower constant amp draw than the rated 125, why are they rating it for 125? Shouldn't they rate it at 80 or something then?

[BrianG]

This doesn't really answer your question about the ESC getting hot, but you can set the ESC so it has a more gradual throttle response. This would keep the amperage down somewhat, making the ESC heat less. I changed this setting on mine and didn't notice noticeable loss in power - if anything, standing starts were more controllable. There is also a setting for the types of batteries you have. One setting pulls more current, the other is a little more gentle on the batts. I would think this would also have the effect of slowing down starts and acceleration. Something to think about anyway.

I agree with Gustav; I think it's the heavier load from the grass. The little heatsink on these things are quite small to dissipate the heat required. If you are pulling 115A @ 14.8v, that's 170 watts being dissipated on the controller assuming a 90% efficiency. Frankly, I'm surprised it's just a little hot. Ever feel how hot a measly 75W lightbulb gets after just a few seconds?

Again, this doesn't address your concern about why it's rated for a certain current, yet gets really hot when you draw less. If you can, maybe mount the bottom part of the case on a piece of 1/8" thick aluminum as a secondary heatsink? If it's big enough and you have some type of thermal grease in the joint, it should go a long way to improve temps.