Phoenix 25 Getting Awful Hot - RC Groups
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Apr 03, 2005, 01:00 PM
Glow Free Since Aug, 2005
tommy321's Avatar

Phoenix 25 Getting Awful Hot

Hi guys,

I just bought a new Phoenix 25, and on initial bench running, it seems to be getting awful hot very quickly. I've been flying my 2 AXI 2808/24s around with a Phoenix 35, and got tired of always switching the ESC between my two planes. I prop my AXIs with a APC10x6E prop, and that seems to give me 22A WOT (which isn't needed much in flight). I thought the Phoenix 35 was a little bit of overkill so I chose the Phoenix 25 as my second ESC.

Here's the test setup.
AXI2808/24 with APC 10x6E prop
Deans Ultra Connector on battery side of ESC
Kokam 3S 2000mAh (15C) or Apogee 3S 2480mAh (10.5C)
Medusa Power Analyzer in series between the battery and the ESC.
No servos connected to the receiver.
I initially had my ESC connected to the motor with Sermos Connectors. After the initial observation of a hot ESC, I tried soldering directly to the AXI leads.

I find that if I open up the throttle to read ~5A current draw on my power analyzer, the Phx25 gets almost too hot to touch after about 10-15 seconds of running. 5A corresponds to about 1/4 throttle on my setup. At one point I decided to try changing the programming to make sure the current limiter was "very sensitive" and to try different timings. With the ESC still quite warm, I removed power, moved the stick to full throttle, and reapplied power. The LED would flash, but there'd be no beeps to get me into programming mode. However, if I went to low throttle at this point, I could arm and start the motor. After leaving the ESC for a couple minutes to cool, I found that I could again get into programming mode properly.

As I mentioned above, I initially had connectors between my ESC and the motor. My connectors appeared to be fully engaged, and the motor behaved fine other than the ESC getting hot. In any case, I removed the connectors and tried soldering straight to the motor leads. The ESC still heats up pretty quick.

Just for comparison, I tried running the AXI at 5Amps current draw with my Phoenix 35. It stayed stone cold. I've had probably close to 100 flights with these motors and the Phx35 with good performance and endurance, which leads me to believe that the motors are probably Ok (i.e. no strange shorts in the windings, or high resistance).

I think I'm using fairly new firmware. Like I mentioned, I ordered the ESC last week, and it arrived Friday. It has the Auto-lipo LVC feature which my PHX35 does not have.

I read some of the other problem reports on the forum, and tried to pre-emptively answer most of the questions you guys ask Does the ESC normally get hot when running at low throttle settings? I haven't flown this ESC yet, because I'm worried about an overheat/shut down in flight.

Thanks for your help.

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Apr 03, 2005, 03:24 PM
Registered User
Just a question but what firmware is installed on the PH-25? Maybe 1.11?

If so you might try changing it back to 1.021... There have been several PH-25's melted down(like chips falling on the ground melting) with the 1.11 firmware..

The 1.021 has no issues...

Apr 03, 2005, 06:29 PM
Glow Free Since Aug, 2005
tommy321's Avatar
I don't have the USB-link for these, so I don't know exactly what version of the firmware it is. Here's a picture of the PCB, (if that helps anyone tell what generation it is). I'm sure that these are a high enough volume part, that the ESC wouldn't have sat at the internet hobbyshop for all that long. It's probably fairly recent.

I know a fellow at my club who has a USB programmer for these. I could get him to check the firmware version, and probably roll it back if we figure that's a good course of action.

I did feel like if I let the ESC keep running something would melt eventually.

Thanks again,

Apr 03, 2005, 10:01 PM
tommy321, I have exactly the same problem as you. We also have the same reasons for buying the PHX25.
I have flown using my esc but with some erratic motor behaviour but as I built my own motor I thought that was the problem, not the esc.
I rebuilt the motor, twice, thinking I had a bad wind, still no improvement. Today I tried my old PHX35, the motor runs fine.
My motor is an LRK style outrunner, similar dimensions & performance as your AXI.
When I first got my PHX25 it didn't run the motor very well so I upgraded the firmware from v1.021 to v1.11 which fixed a couple of issues but still didn't run the motor as well as my PHX35 which has v1.081 firmware. My motor draws 18.5A at WOT spinning an APC 10x5 at 7500rpm. That's using the PHX35.
I didn't realise how hot the PHX25 was getting till today, especially at 1/4 throttle. I won't use it now till I get the problem sorted.
Shawn at Castle Creations told me I can't change the firmware back to a previous version. I better contact him again to update him on my problem, although he might read this post.
Apr 05, 2005, 11:37 PM
I have the same problem except I'm using 3 cells 1200 mah on a scatty motor, doesn't go over 12A. If I run it static or if I hover it gets hottt. Also, I cant run cd-rom motors on this esc, if I go above 50% throttle, the motor starts making a lot of noise... 17 turns wye 1x22.7mm stator, ball bearings.... My whole purpose for getting this esc is so that I could use it on Cdrom motors... and no go, now I'm pretty much stuck with nothing, and I purchased this new like 2-3 weeks ago...
Apr 05, 2005, 11:39 PM
"Shawn at Castle Creations told me I can't change the firmware back to a previous version. I better contact him again to update him on my problem, although he might read this post."

So if we got ours with a newer firmware, we cant use the older one that actually worked? why do they update the firmware if it doesn't work???
Apr 11, 2005, 02:12 PM
Flying R/C since 1964
kallend's Avatar
Originally Posted by KillerCut
"Shawn at Castle Creations told me I can't change the firmware back to a previous version. I better contact him again to update him on my problem, although he might read this post."

So if we got ours with a newer firmware, we cant use the older one that actually worked? why do they update the firmware if it doesn't work???

Take a look at this thread:
Latest blog entry: Using a DX9 to "strobe" LED...
Apr 12, 2005, 09:42 PM
Thanks for the link Kallend. I'll try that procedure.
BTW, I put stronger mags in & rewound my motor to improve efficiency. The motor runs fine now with v1.11 firmware but the ESC still gets very hot at 1/2 throttle. I'll ask CC what gives.
8x kan 1050
12.5A at WOT APC 9x6e (broke the 10x5)
4x GWS naro maxbb
at 1/2 throttle 4.5A

Apr 13, 2005, 10:33 AM
Castle's Chaos Corner
Bernie Wolfard's Avatar

Please mail me directly on this:

Apr 15, 2005, 11:45 PM
Registered User
I too, just received a Phoenix 25 today in the mail that can also be used as a heater. I ran two motors (Himax 2025-5300, and E-flite Park 370 outrunner) with a three cell pack, and it gets too hot to touch in less than 20 seconds at 1/4 throttle drawing only 2.5 amps. I tried updating the firmware, and the different program settings. Nothing helped. I wonder if there is a production problem that we are experiencing on the 25's that is slipping through quality control? It would be nice to hear from CC if they have any more information about our problem.
Apr 16, 2005, 05:13 PM
Glow Free Since Aug, 2005
tommy321's Avatar
Bernie emailed me that it sounded like a hardware problem on the P25. He's currently mailing me a replacement along with a mailing bag to return the suspected defective one.

Hopefully he might be able to update us when he gets my P25, and they have a chance to look at it.

Apr 18, 2005, 08:37 PM
Registered User
I talked with Castle Creations this morning. They are sending out a replacement Phoenix 25 including prepaid return postage. Great Service!! They speculated that one of the phases may be dropping out causing the overheating problem.
Apr 25, 2005, 03:31 PM
Registered User
I am also getting a very hot Phoenix 25.
As this is my first brushless I considered it must be normal all though it became rapidly to hot to touch at part throttle. During flight I am getting motor cut outs, more often at ¼ - ½ throttle that can be reset with low stick. This has caused the loss of an airframe as the dead stick caught me with my pants down.

The ESC is only 3 weeks old. I don’t know the firmware version as I have no link (so far)

The ESC has been getting hot enough to melt the plastic cover (see pic), but strangely over just one chip(middle of the 3), the other side is fine.
I guess there is a problem. Hardware or software?

Apr 25, 2005, 07:05 PM
Permanently Banned
Larry3215's Avatar
Vince - More details would help...
How many and what kind of servos?
What motor?
What gear box ratio?
What prop?
What battery?
What plane?
Does the motor start smoothly?

Good luck!

Apr 26, 2005, 04:41 AM
Registered User
1st plane was a Ripmax Alliance. Now using a GWS Formosa.

Kokam 3s1p 2ah (cell slpb834374H). 15C claimed – 30A

HET Typhoon 15/10

Graupner slim 9-5 (direct drive)

3 x HS81

Its pulling about 20A static. If I just add a bit of throttle it will ‘twitch’ in either direction but runs OK if I add a bit more, but I would not exactly call it a smooth start.

The HET manual says the motor runs best with greater then 20deg advance so I have the ESC set to High advance 12-35, low being 5-20.


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