Author Topic: brushless motor and ESC How do I choose the right combo ?  (Read 6025 times)

Offline kj

  • Full Member
  • ***
  • Posts: 108
  • Country: us
brushless motor and ESC How do I choose the right combo ?
« on: June 05, 2010, 06:40:10 PM »
I just finished building an EXi 450 kit. I installed a 3800kv Esky bl motor and 25a esc from a crashed king2. All was good for a few minutes then while trying to take off again there was a large puff of smoke. I t appears that the motor burnt up.   There are so many choices of motors and ESC's  can anyone suggest a combo that will work and not cost an arm and a leg ?  I am using (2) 11.1v / 15c / 1350mah batteries in parallel. Any and all input is appreciated. Thanks. :132:

Offline pinguin6218

  • MOTM Award
  • Legend
  • *****
  • Posts: 4734
  • Country: id
  • Practice makes perfect
Re: brushless motor and ESC How do I choose the right combo ?
« Reply #1 on: June 06, 2010, 07:09:36 AM »
Are you sure that the motor that went in smoke not the ESC ?  Because Esky ESC is easy to catch fire.
If you need ESC, better get a 35A and above
   Be Blessed

Offline Nuttcaze

  • I've been lost for a very long time.
  • Administrator
  • Elite member
  • *****
  • Posts: 2847
  • Country: us
  • Fly it like you stole it!
    • My RC Guides
Re: brushless motor and ESC How do I choose the right combo ?
« Reply #2 on: June 07, 2010, 12:21:12 AM »
I just bought 2 of each of these, they work great, especially the motors, I've owned about 7 in the past with no problems  :125: :confused:


Alpha 400 (3500kv) Brushless Motor for 400/450 RC Helicopter $11.70 - http://www.hobbypartz.com/alpha-400--3500kv--brushless-motor.html




30A Brushless ESC Speed Controller [Hobbywing] $11.00 - http://www.hobbypartz.com/30a-electronic-brushless-esc-speed-controller--volcano-series-.html

HK 600GT - Chaos 600/Bell 206        MyRCGuides Website

Offline kj

  • Full Member
  • ***
  • Posts: 108
  • Country: us
Re: brushless motor and ESC How do I choose the right combo ?
« Reply #3 on: June 07, 2010, 06:31:26 AM »
Thanks for the reply fellows...Yes it was the motor that went up in smoke. It did not appear to hurt the ESC.  But I will replace it anyway. The Alpha 400 and 30A esc you suggested Marc, is what I had planned on replacing the Esky bar-b-cued parts with.  I think I figured out the problem : when I put the 2 batteries in Parallel  the thing I did not consider is that they then became a 6s lipo. Maybe that is why the motor fried.??? I would have thought the ESC would go first....Live and learn (spend more $ )   thanks. :218:

Offline Blackrain0119

  • Forum Service
  • Legend
  • *****
  • Posts: 3471
Re: brushless motor and ESC How do I choose the right combo ?
« Reply #4 on: June 07, 2010, 06:49:30 AM »
Good luck!
Trex 700 Trex 600 Copter x v2 Exi 450 x5 exi 250

Offline stalls

  • Jr. Member
  • **
  • Posts: 83
Re: brushless motor and ESC How do I choose the right combo ?
« Reply #5 on: June 07, 2010, 08:42:59 AM »
If you put them in parallel that would've only increased the capacity, not the voltage i.e it would have still been 11.1V 3S @ 2700mah (1350mah x 2).
Are you sure you didn't put them in series i.e. 22.2V  6S (11.1V x 2) @ 1350mah?
'mah' shouldn't kill an ESC or motor, only too many amps/volts.

(I'm no electrician, but I'm confident that's right)

Parallel should have both of the Red wires connected

Batt 1       Batt 2

Red  ----->Red---->ESC Red
Bacl ----->Black--->ESC Black


NOT
Batt 1       Batt 2

Red  ----->Black---->ESC Red
Bacl ----->Red--->ESC Black

Offline stalls

  • Jr. Member
  • **
  • Posts: 83
Re: brushless motor and ESC How do I choose the right combo ?
« Reply #6 on: June 07, 2010, 08:44:05 AM »
My AWESOME diagram should guarantee me member of the week!! :woohooguy:

Offline Nuttcaze

  • I've been lost for a very long time.
  • Administrator
  • Elite member
  • *****
  • Posts: 2847
  • Country: us
  • Fly it like you stole it!
    • My RC Guides
Re: brushless motor and ESC How do I choose the right combo ?
« Reply #7 on: June 07, 2010, 09:50:55 AM »
nah, we need pics, lol, jk



HK 600GT - Chaos 600/Bell 206        MyRCGuides Website

Offline tcprogrammer

  • MOTM Award
  • Hero Member
  • *****
  • Posts: 1286
  • Country: us
Re: brushless motor and ESC How do I choose the right combo ?
« Reply #8 on: June 07, 2010, 10:10:09 AM »
If you put them in parallel that would've only increased the capacity, not the voltage i.e it would have still been 11.1V 3S @ 2700mah (1350mah x 2).
Are you sure you didn't put them in series i.e. 22.2V  6S (11.1V x 2) @ 1350mah?
'mah' shouldn't kill an ESC or motor, only too many amps/volts.

You are on your way to be an apprentice electrician!  You are correct, the battery capacity or battery discharge rating ('C' rating) can't hurt the motor. The motor will only draw the current it needs.  The voltage on the other hand WILL damage the motor if its not designed for that voltage.
Part time rc pilot, full time rc mechanic!
MSH Protos - DS3517 cyclic, stock motor/esc, MSH Brain FBL
CX450 SEv2 - DS410M cyclic, scorpion 2221-8/60Amp, Quark+MKS8910 tail
LAHeli Ricco - YGE ESC, Quark+MKS tail

Offline Wayne

  • MOTM Award
  • Legend
  • *****
  • Posts: 5901
  • Country: us
    • Flying Eagles INC
Re: brushless motor and ESC How do I choose the right combo ?
« Reply #9 on: June 07, 2010, 11:53:51 AM »
I gotta make up some of those.  It's on my list of stuff to do as soon as I get hands on some 14g wire.
I don't always fly a good gyro, but when I do, I prefer Vbar...Stay inverted my friends!

eFlite MSR, HBFPv2, Align 250, HK450GT, EXI 450, EXI 500, Raptor 30

Offline kj

  • Full Member
  • ***
  • Posts: 108
  • Country: us
Re: brushless motor and ESC How do I choose the right combo ?
« Reply #10 on: June 09, 2010, 06:37:25 AM »
Thanks for all the replies. I had the batteries wired up "parallel"    positive to positive and negative to negative.   According to my PRECISE calculations (lol) the only thing that should change is the mah rating.  When I started to spin up the motor I went about 2 clicks on the Tx and the motor started to turn and then it stopped. I paused for about 2 seconds (stick still in the same position) then when I throttled up that is when she went up in smoke. Maybe when I paused there was still voltage going to the motor and when I throttled up it overloaded. When I checked the heli there was nothing binding everything turned freely. I was actually trying to start the head spinning very slowly.   My concern is if I connect my batteries PARALLEL again  will I have this problem again ?  :132: I personally like using 2 batteries. It allows me to get the CG perfect. Now I'm a little nervous about connecting the batteries parallel again. :117:      :225:It came to me just minutes after posting this. What are the odds that just "slapping" the motor on and not setting the lash caused the binding problem ? You know...due to imperfections in the main gear. Tight on one side and loose on the other side. Combine that with throttling up very slowly and a dummy at the controls you just might get a burnt up motor .... :220: