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Should a 20A (30A Peak) ESC Overheat with 10A draw?

#1
Hey All! I'm new to this board and the hobby, but I've been learning quickly. I built the thrust meter that Josh shows in one of their videos and while running a 2200kv A2212-6 brushless with a 9x6 prop it just cuts out after 30 seconds. I still have to see if it will run longer or until a batter is depleted at a lower throttle. The first (more expensive one with a nicer heat sink) 25A ESC went into "oh crap" mode and rebooted, the second 20A/30A SimonK ESC doesn't have any fail-safes so it just died (RIP) it also doesn't have a very good heat sink. I have 3 more of that ESC, but now I'm afraid to use them.

I went back and my more expensive ESC (25A) is still working. I ran it for a while through my watt meter and was getting the following data...

11% Throttle (when it starts) I get .62 A and 7.3W
15% = 1.6A and 19.9W
27% = 7.8A and 94W

I then bumped it up to 33% and it quickly shut down. ESC was CRAZY hot and it's as in the flow of air as possible, without building a platform behind the prop so the ESC is directly in the line of thrust; right now it's on a post in front of the blade (not blocked by the post, as in the incoming air as possible...

Should I try a smaller or slower prop? Anything else?
 
#2
More Information...

I will note that according to the Amazon product page, the 2200kv motor is rated at 12A/60s max; 4-10A 80% Efficiency.

Specification:
1. Model: A2212/6T
2. KV: 2200
3. Max Efficiency: 80%
4. Max Efficiency Current: 4-10A (>75%)
5. Current Capacity: 12A/60s
6. No Load Current : 10V: 0.5A
7. Number Of Cells: 2-3 Li-Poly
8. Motor Dimensions: 27.5 x 30mm
9. Shaft Diameter: 3.17mm
10. Weight: 61g

So, based on a Max 10A operating current and say 12 volts for a charged 3s 2.2Ah battery, can I only expect 120 watts out of this motor AND AT MAX THROTTLE??? I'm going to try to run some tests with smaller props if I can find some that fit.
 

quorneng

Well-known member
#3
smithhayward
With a 9x6 you are seriously over loading a 2200kv A2212-6!
You don't say what battery you are using but Hobby King suggest a 7x4 on a 2s and a 5x5 on 3s and even then with a 40A ESC!
A 20A ESC is just not suitable for that motor.
You need the right prop and a 40A ESC then it won't overheat.
 
#4
Thanks! What about putting the 9x6 on a 350 size 1360kv? Again, depending on the motor's specs, but does that sound more appropriate?

I'm running FLOUREON LiPo 2200mAh 3s 25C packs.

Do I understand this right, the prop diameter sort of relates to how much air a prop can move, and the pitch is how fast it moves the air? And the combination of the two control the amount of work a motor is going to need to do in order to propel a vehicle?

Maybe I'll use 2 of these 2200kv's with 5x5s on a dual-motor setup for my next plane. What about going to a 3-way prop?
 

quorneng

Well-known member
#5
Sorry I got the wrong motor but you are still seriously over loading the A2212-6 it with a 9x6 which is why the ESCs are failing/overheating.
The recommended props are 4x4, 6x4 or 5x5 for a 3s.
With a 5x5 it will draw something like 19A which is about 200W.
 
#6
OK, Thanks for letting me know - so I should still upgrade to at least a 25 Amp ESC (one that can sustain 25 amps) right? or should I go all the way to 40 to be safer?

200W sounds like enough power for my application.
 

Epitaph

Ebil Filleh Pega-Bat ^.^
Mentor
#7
Might not be the case in this instance, but just remember that you also have to look at the power capabilities of the BEC...
 
#8
Yes, these have either a 2A or 3A BEC. I've gone ahead and purchased a few more higher-amp ESCs and lower Kv motors to experiment with. I already have some 9x4.5 props as well. I built the Tiny Trainer and it didn't fly as good as I had hoped, seemed to need full-throttle to stay aloft. THAT SAID, I forgot the wing dihedral and put in a 1200mAh battery (heavier than recommended), and used only the minimum 5x3 prop on a 1360kv motor, so it's surely not the plane design's fault. Maybe I'll rebuild it with some landing gear once the new motors and ESCs arrive. Maybe I'll try my hand at slightly modifying the wing area and add flaps (I know it will slow down) to increase lift so I can shove a 2200mAh 3s in there. Other than space, weight and CG, are there any other reasons not to try increasing mAh for increased flight time? (Or does the added power required to haul the added weight eliminate any gain?)
 
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ZoomNBoom

Senior Member
#9
The rated amps for a motor is not what it will pull under load. Its what it should be able to pull without melting. You are severely overpropping and as result, either the ESC or the motor will shut down or produce magic blue smoke. You can upgrade the esc, but the only result will be a smoking motor instead. Just get a much smaller prop.

BTW, good points for the motor for surviving 20+A needed to melt your ESC's. Its only rated for 12A bursts. That is, if it did survive, good chance you did melt wires in there.
 
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quorneng

Well-known member
#10
smithhayward
If increasing the flight time was as simple as just putting in a bigger battery then everybody would be doing it.

You are quite correct that increasing the plane's weight increases the power it needs to fly which in turn takes more out of the battery. It will fly for longer with a bigger battery but it is a case of diminishing returns. In addition as the weight increases the plane will become progressively harder to control and the extra weight means it will break more easily in any crash!

Batteries are relatively heavy so the best course of action is to make the most efficient use of the energy it contains by coupling it up to the appropriate ESC/motor/prop combination for the plane.
The difference in performance and duration between a 'good' and 'poor' motor set up can be huge.
 
#11
Thanks everyone for all the help and suggestions! I knew this community would be awesome. So...

I've trashed the Tiny Trainer. Just wasn't feeling it anymore. So I'm building the Storch. I have A few motors to pick from and was wondering if any of you have a suggestion.

Park 480 1020kv
Leopard 1020p
E-max 935kv

I have plenty of high-amp ESCs now (2 40A and 1 25A) so whatcha think?