Question on 'normal' ESC Temps

[jb31d]

I have completed two short test flights so far mainly in a low hover to check control services and Vbar function, but no forward flight as of yet.  At the end of both flights (between 3 and 4 minutes respectively) When I have been unplugging my battery for power down I have touched the ESC and motor to check the temps and both seem more warm than they should be (in my uneducated opinion).  After the first flight I was making some adjustments to the ESC in Castle Pro and checked the logs which indicated the temp was roughly 150F, and based on the temp to touch after the second flight I believe it was roughly the same for that flight as well.  I am concerned this high temperature is abnormal and am hoping to get some feedback on the recommended settings for a 120HV (to verify the settings I set) as well as to see if this temp reading is abnormal.

I'm running the 4025-1100 on a stock E5 setup with 120HV ESC (governed @ 2100 & 2300) and CC BEC Pro (@ 7.5v).  I'm powering everything with a Pulse 35c 5000, and I replaced the stock Scorpion bullets on the motor with the CC 6.5 bullets per RichL's suggestion.

I just want to make sure I'm not going to burn anything up.  I suppose with some forward flight/airflow the temp would be lower???

On the upside, the Vbar is working great and just needs some minor tweaking.  Thanks in advance.

[steffgiguere]

ESC should be around 160, therefore at 150 you are good.

[jb31d]

Right on!  In that case, I'm going to charge up some more batteries and get after it.

Thanks.

[curmudgeon]

I'm running the 4025-1100 on a stock E5 setup with 120HV ESC (governed @ 2100 & 2300)...

Congratulations on your maiden flights.  Although the Castle ESC's allegedly can handle over 250F, higher than ideal ESC and motor temperatures during the non Summer months may be an indication that there is room from improvement.  According to the MrMel calculator http://heli.dacsa.net/calcv3/Default.aspx, with your system of 119T main gear,  1100Kv motor, and Castle governor, the 13T pinion may give you the HS you are looking for, keep the Castle governor within the happy range, and optimize the ESC and motor efficiency (and temperature).

If using the VBar governor, you can go down to the 12T pinion for those HS's, and run the ESC and motor even cooler.

[jb31d]

To make sure I understand, you are saying it would actually be better overall to change out to the 12T pinion instead of the 14T to keep the same head speeds I have?  This seems counter-intuitive to me, but I readily admit I am still learning all the ins and outs of the electronics.

[curmudgeon]

Plug the numbers in the MrMel calculator http://heli.dacsa.net/calcv3/Default.aspx, and this may become clearer.

For your 1100Kv motor running on 35C 6S, with the 14T pinion:
(1) VBar governor "sweet spot" head speed range 2,465-2,564rpm.  If you go below 2,382rpm, you loose efficiency and both motor and ESC run hotter.
(2) Castle governor will show the "warning" at 2,456rpm.  Same low 2,382rpm as VBar.

So, for your desired HS range of 2,100-2,300rpm, the 14T pinion is not ideal, and would explain in part why the ESC and motor are running hotter than you would like.

Go down to the 13T pinion:
(1) VBar 2,289-2381rpm, but don't go lower than 2,212rpm to keep ESC/motor cool.
(2) Castle warning at 2,280rpm.  Same low of 2,212rpm as above.

Go down to the 12T pinion:
(1) VBar 2,113-2,198rpm.  Low of 2,042rpm
(2) Castle warning at 2,105rpm

The VBar can govern higher HS more effectively than the Castle governor for any given pinion.

For your desired HS range of 2,100-2,300rpm, the 2,300rpm is better governed with the 13T pinion and the 2,100rpm with the 12T pinion.  Since you probably won't be able to govern 2,300rpm with the 12T pinion, you may just use the 13T pinion, and understand that you will loose efficiency at lower than 2,212rpm which manifest as ESC and motor run hotter.

BTW, if you go with 2,100rpm, and want solid tail authority with the 96mm tail blades, the optional 4.5 tail ratio is the way to go to keep the tail spinning between 9,500-10,000rpm.

[jb31d]

Thanks.

[hardsy]

JB,

I was running the 14t pinion, same motor with similar headspeeds and was getting ESC temps around 185deg.

I have sinced changed to the 13t and esc and noticably the motor temps are much cooler.

Definately worth changiong IMO for those headspeeds, also marginally better flight time

[jb31d]

I think I might end up doing that after a little bit.  I'm still getting comfortable with everything right now and don't want to rush to make any physical modifications just yet.  After talking to other folks I feel a little bit better that nothing I have been seeing is out of the ordinary.