Why am I running HOT?!?!

Mactadpole

Mactadpole

Member
I have a quad that I built with spare parts for fpv and gopro gimbal. It seems like a proper build and ecalc seems to confirm that but the ESC's and motors are hot after 5 minutes of flight and very hot after 14 minutes. I have tried 3 different ESC's, two different motors, two different props, and two different batteries. Not much difference in temperatures between those combos. Here is the build specs with commas separating the different bits I have tried in every combo:

Rusty UAP 1 frame @ 680 mm motor to motor
iPower 2814 750Kv, currently Avroto 2814 770Kv
ZTW Spider Opto 30A ESC's w/SimonK, ZTW 30A ESC's (regular), currently Hobbywing XRotor Opto 40A ESC
APC Slowflyer 12x3.8 & 11x4.7
3DR Pixhawk on 3.2.1, 3.3-rc9, currently 3.3-rc11
Vulcan PDB board
1.3 ghz fpv system
Z-Tiny2 GoPro gimbal (using dummy weight till I get it flying properly)

AUW without battery is 2305 g, and I have been flying with Multistar 8000 mah 4S 10/20C (649g) or Zippy 5800 mah 4S 25/50C (569g)

Pretty much no matter the setup it flies just below mid-throttle, except 8000 mah batt. and 11" props. I have been able to get it very nicely tuned but the ESC's and motors are both what I consider very hot after a full battery. All the ESC's I've tried are too hot to keep my fingers on them for more than a few seconds.

Am I just asking too much from these 2814's? I have used this motor a lot in the past and never had such heat issues. What am I missing?

ecalc info attached and pic of copter with dummy weight for gimbal and iPower motors that are now Avroto.

IMG_2608.jpg
Screen%252520Shot%2525202015-09-12%252520at%2525208.55.31%252520PM.png
Screen%252520Shot%2525202015-09-12%252520at%2525208.55.53%252520PM.png
 

Old Man

Old Man

Active Member
You should be able to use the 12" props with no problems. My initial thoughts are the ESC's are not what they are cracked up to be. Barring that, look at all the wire connections and wire sizes and assure everything is right with those. Might try changing out the XT60 connectors for EC-5 at some point. I'd actually do that first.
 

Mactadpole

Mactadpole

Member
Yep, I've run these same motors in the past with similar configurations on probably 4-5 rigs with 11-13" props no problem. I've used 30A esc's in the past with them so I know they should work but I decided to try the HW XRotors 40A to see if that was somehow it. I am only pulling like 25 amps in hover so I should have known it wasn't the ESC's. I've used XT60 and XT90 on all my rigs for a while now and never had an issue.

The main difference is the Vulcan PDB and I think that might be it. It was a b*%$! to solder. I am going to put an "octopus" style power system together and see what that does. Thanks for getting me to think about power distribution!
 

Old Man

Old Man

Active Member
That Vulcan plate soldering is a cast iron beatch! I did one too and they are difficult to do get a good bond at one point without disturbing the bond at another point. PDB designs are something that could really be improved upon to minimize or eliminate soldering. There is no need for them to cost hundreds of $$ to function well. The only problem is designing a good one and selling enough of them to cover your time and expense before some oriental outfit steals your work and markets them for 1/10 of your selling price.

Now that I think about it, if one had the room and inclination there's no reason someone could not experiment with a couple of the Vulcan plates stacked up together, using fixtures for spade or ring connectors. You just got me to thinking about those plates and spot welding on some attachment points. However, it would be a lot cheaper to just buy some copper discs and go at it. Easier still would be to make up a PDB from a high current capacity breadboard by adding connectors. I can see it now, one stop PDB shopping at DigiKey or Mouser...
 
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Motopreserve

Motopreserve

Drone Enthusiast
I've had good luck with the Vulcan board. But I do jack the iron quite a bit and don't have to leave it on the board too long. I also add a bit more prep solder to the pads than I normally would.

@Pumpkinguy made a nice DIY PDB with a copper disc/washer and added bullets. I may try this if I can steal an old hunk of 2.5mm copper from an old computer I have.
 

violetwolf

violetwolf

Member
I was thinking pdb or wire gauge too. What gauge wire are you running from pdb to ESC's ?

Wire gauge from batteries to pdb?
 

Mactadpole

Mactadpole

Member
violetwolf said:
I was thinking pdb or wire gauge too. What gauge wire are you running from pdb to ESC's ?

Wire gauge from batteries to pdb?
Click to expand...

I soldered the Pixhawk power module directly to the pdb and it has 14g wire and then the wires to the ESC's are 16g as are the stock wires from motor's to ESC's. The motor wires are about 10 cm longer than they need to be so will get those cut down too.
 


Mactadpole

Mactadpole

Member
Motopreserve said:
Any chance you've used a different brand of wire than the other builds that used the same components?
Click to expand...

Used what I had in my stock. Really didn't have to use much wire since both motors came with bullets which plug right into the ESC's, added about 8-10 cm of wire from stock between ESC's and PDB, no wire added between PDB and power module.

All the motors and ESC's are evenly hot.
 


Mactadpole

Mactadpole

Member
Motopreserve said:
How dos you add the wire between esc and PDB? Bullets? Or straight soldering???
Click to expand...
With the first set of ESC's (ZTW spider 30A) I did have them straight soldered. I added bullets to the PDB wires when I switched to the next set of ESC's because I didn't want to remove bullets from ESC's. This is how I typically setup my PDB's, short wire from pad with bullet. Never caused a problem.

We will see later this week if the octopus style power system fixes the problem. I will report back for sure.

Here's a pic of the PDB I normally use. Have used it on Y6 (680 mm), X8 (800 mm), Hexa (900 mm), and Hexa (1080 mm). All on 4S or 6S batteries with pigtails from the board and bullet on the end for ESC connection. Never had a problem. Think I need to buy some more of these.

dys-10v-20v-power-distribution-board.jpg
 




Mactadpole

Mactadpole

Member
I should add that with this PDB and the new EKF interference monitor in the Arducopter 3.3 beta I see no influence on my big hexa. I did see a slight impact on the compass in the EKF monitor with the quad and Vulcan board.
 



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