[secant0give]

Nice graph. That ESC is getting extremely hot.

What do you think is causing the rpm and voltage to drop when you throttle up? Is this prop loading when you release the bird in to the sky?

Did you doppler the video to see if the RPM is correct?

Dave you allways ask good questions

Your right Dave it does look as if it's getting hot. I'm not sure where on the board the temp is measured, or even if it's being scaled to represent the hotest temp in a place near where it's measuring.
It does look like it's trying to monitor and feed back to the controller in the second flight between 900 and 975 seconds as the temp line is pretty flat, at it's max point, it's like it's plateued.

It promped me to send the following email to their support people:

G'day,
I purchased an Icelight 100 ESC to use in my shoestring after the Icelite 75 ESC I purchased burned.


I am using the standard EF1 set up in my Eflight shoestring 15, this is as follows:

2600 mah 4S Lipo pack
E flight power 25 1250KV motor
8X8 APC thin electric propeller
Icelite 100 ESC

I see from the temperature line on the Data logger chart that it is reaching nearly 100 deg C
This is quite a high temperature for electronic components to deal with. The ESC is only drawing just over 60A I've attached an image of the graph from the Data logger.

My questions are:

1) is this the normal expected running temperature?
2) Where abouts is this temperature measured from on the board? It it measured very close to the fets? if so is it the actual measured temperature or is it scaled to represent the Junction temperature of the fets?
3) what is the maximum temperature that it can run at continuously.
4) What is the maximum junction temperature of the Fets used in this controller (Tc)
5) looking at the graph of the second flight I can see the temperature seems to level out at around the 900 second mark. Is this some kind of temperature monitoring and feed back that the ESC is doing internally? The temp line looks unnaturally flat between 900 and 975 seconds.

Many thanks

Jason Vanajek

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I guess you'd expect to see the prop unload in the air this is the case mostly, but with steep piched props, they can actually draw more current when they get moving. This one is an 8X8 so it's conciderd steeply pitched.

What you see in the graph while things are steady, ie the throttle is wide open, I think is the usual voltage and current dropping over time with the dischargeing of the battery pack. There might be some current limiting being done by the ESC because of the high temprature. This is not very apparent in the current (Amps) line but the temp line looks like it might be that way. The plateu we see in the temp line could also be what ever they are using to measure the temp maxing out, tho' I doubt that.

I would expect the current to rise steeply as the throttle is opened and as the current rises the voltage gets pulled down due to the internal resistance of the lipo's.

The RPM falls off slower than the current and the voltage during the times when things are steady ie the Throttle is wide open. I would expect this, as the "power required" to RPM ratio is not liniar. ie it takes much more than 10% greater power to obtain a 10% gain in RPM. So that part of the chart looks plausable.

I did a pitch speed calculation and it was about 170kph at peek I think this is roughly believable as it's probably doing about 135-145 kph in the air. I havn't done a dopler shift measurement but on the face of it I would think it will agree fairly well. I will do it none the less as soon as I get some better video and have the model nicely trimmed and dialed in. It's only had two flights thus far