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Limits of the 1806?

mrf

New member
#1
Hi everyone,

I recently got a runcam2 and have flown it on both the FT Arrow and Mini Mustang, both using the 1806 from the A-Pack (with a 12amp ESC). Both attempts have cooked the motor that was attached at the time. Any attempt to power it up just results in the prop shuddering back and forward.

The ESC appears to be unscathed as attaching a new motor to it works (seemingly) without a problem.

Just wondering where the bottleneck is here, is it:

a) the 1806 is just too underpowered for the job and is melting; or
b) the ESC can't deliver enough current and is burning out the motor.

Hoping to get some 2204s in the mix soon, however being in Australia I have to get them delivered from China and that usually takes aaaaages!

Thanks in advance for your help/experience!
 
#2
If your motor is twitching like that it seems likely that one of the phases has been burnt (3 phases coming from the esc). The motor must be drawing more watts than it can handle, so a larger motor is probably going to solve the problem. It surprises me that your esc wasn't overworked by the current draw from the motor. I guess it stayed under 12a. I have a motor that does the twitch, but I fried the esc too. Luckily the battery came out alright.

There's got to be some sort of payload calculator that can estimate prop, motor, and esc for a plane. Maybe someone with more experience will chime in.
 
#4
Could be over-propped. What size and pitch prop are you using?
Yeah, I think you may be right. Either way, the motor is drawing more current than it can handle. It may be that the larger motor will fix the problem by itself, or it could just push the problem over to the ESC. So for now motors are burning, next time it might be the ESC, and after that maybe the battery itself depending on C rate.

Whatever you do make sure that the motor draw is well inside the ESC's ability to supply power. Do you have a watt meter to test the wattage draw of the motor on the bench (with a prop attached)? This won't add the extra work required for the runcam, but it should tell you if you need to set your throttle limit to keep the wattage at a safe level. I'm not sure how to calculate the extra wattage of the payload, but I would guess that you might want to set your limit under the "safe" limit that the watt meter gives you.
 
#5
Has your motor EVER worked right? I had one that would shudder and I realized it was a bad solder connection in one of the bullet connectors. Could it be that?
 

cranialrectosis

Kite Eating Tree Trimmer
Mentor
#6
Bad solder between the ESC and motor is a biggie here, particularly if the motor leads are stiff copper wire (coated with enamel).

I have powered a tiny trainer with a 6045 prop on 3S with an 1806 with no problem (12A ESC). It's peppy with the sport wing with that power plant and the tiny trainer is more drag than the mini P-51.

I'm with liamnave. If the motors are twitching when you try to give them power, STOP. If you push it, you will likely torch it. Re-solder the motor leads to the ESC at that point.
 

TazRC

Obsession, not hobby
#8
I suggest getting a wattmeter too so you can see how many Amps the motor is drawing with a particular prop.
 

mrf

New member
#9
Thanks all. It's running on a 6045. I've got bullet connectors between the motor and ESC and did notice that one of the wires leading into them was folded over a bit - so I'll check and re-solder.

Will definitely check out those Brisbane suppliers too!

Thanks again!
 

cranialrectosis

Kite Eating Tree Trimmer
Mentor
#10
ImpulseRC is Soma (RCGroups Soma). This is the guy who invented the WarpQuad and the Alien. His neighbors are Blackout. I have ordered from Soma several times always with good results in both service and quality.
 

mrf

New member
#11
Argh! So it happened again on the Mini Mustang, this time without the RunCam attached.

I was using the same ESC but a different motor. All the solder joints on the bullet connectors look to be ok.

I'll get it all unpacked on the bench tonight, but I'm starting to wonder whether I'm over-propped with the 6045.
 

mrf

New member
#12
ImpulseRC is Soma (RCGroups Soma). This is the guy who invented the WarpQuad and the Alien. His neighbors are Blackout. I have ordered from Soma several times always with good results in both service and quality.
I thought the name sounded familiar! It was only when I went to the site and saw the logo that it clicked :p
 

TazRC

Obsession, not hobby
#13
Argh! So it happened again on the Mini Mustang, this time without the RunCam attached.

I was using the same ESC but a different motor. All the solder joints on the bullet connectors look to be ok.

I'll get it all unpacked on the bench tonight, but I'm starting to wonder whether I'm over-propped with the 6045.
From what I've read, a 6030 prop pulls 11-plus Amps with similar 1806 motors so I would imagine a 6045 might be over the top. Can't hurt to try a 6030 or 5045 prop but you would know for sure with a wattmeter. ;)
 

earthsciteach

Moderator
Moderator
#14
That motor should handle a 6045 on 3s. If anything you should be frying the esc. Is the motor rubbing on anything? Have you tried with a different esc?
 

TazRC

Obsession, not hobby
#15
Good point on the rubbing. Mounting screws could be too long.

P.s. Many posts on RCGroups say the Emax 1806 runs too hot with 6045 prop (15-plus Amps on 3S) but a wattmeter will tell you for sure.
 
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mrf

New member
#16
Thanks again for the input all.

The motor was pretty warm to the touch when I picked it up. I will check out the screws as that is a common element between the two runs. I did check them when I attached the motor though and I couldn't see anything fouling, but that could just be me not looking properly :D

I'll see what I can find with a Watt meter, might have to shop online as I'm in regional Australia. Is it something that you test on the bench, or in the air?
 

cranialrectosis

Kite Eating Tree Trimmer
Mentor
#18
I have run a quad copter and a tiny trainer on emax 1806 2300 kv motors on 3s with 6045s for years. Never had any trouble.

I concur with earthsciteach. If the solder joints are good and you don't have a twitchy motor, look for mounting screws too long or the bell rubbing on something. You may have an ESC out of time but I think you would hear it and see it desynch.
 

mrf

New member
#20
Think I may have found the cause of the problem!

IMG_8391.JPG

Looks like the motor has got too hot and melted through the plastic shielding of the connectors :S

So I guess that means I'm driving the motor too hard with the 6045, or that I should have paid the .50c extra and got a genuine Emax rather than a cheapo rip off (or a combination of the 2) :D