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RC Models => Electric Planes => Topic started by: Aeroresurrect on July 17, 2016, 01:32:10 PM

Title: Motor wont go to full speed
Post by: Aeroresurrect on July 17, 2016, 01:32:10 PM
Hi experts,

Need some precise analysis from you !

My electric powered (Wingdragon 300) lying idle for some time.

However, now when I recently fully charged the LiPo and transmitter batteries and tried to check the controls, I found after 1/4 throttle, the motor died. All other controls were working (rudder, elevs etc).  Only after reducing throttle to zero it started up but again died after crossing 1/4 throttle !!!

Wonder if the LiPo is too old (3 years) or it is the ESC problem or the Transmitter problem ?
Title: Re:
Post by: sanjayrai55 on July 17, 2016, 01:52:47 PM
Give full details of motor, prop, ESC and lipo, including lipo C rating. Do you have a wattmeter?

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Title: Re:
Post by: sanjayrai55 on July 17, 2016, 01:53:18 PM
Most probably the fault is with your lipo

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Title: Re: Motor wont go to full speed
Post by: Voice of deaf on July 17, 2016, 03:00:27 PM
Voaltage sag under high load.
Try with a diffrent lipo.
Title: Re: Motor wont go to full speed
Post by: kiran rc on July 17, 2016, 07:10:23 PM
Check out for a loose connection between Esc and motor. In such a situation, excessive current draw will cause it th shut down.
Title: Re: Motor wont go to full speed
Post by: K K Iyer on July 17, 2016, 11:42:26 PM
@aeroresurrect,
When the battery gets low, the ESC will cut power to the motor, and feed only the Rx and servos, so that controls will be available for an emergency landing to be made.
Further, in case power is required to clear an obstacle while landing, the ESC will power the motor for a short while if the throttle is reduced to idle before opening.

Hence looks like a case of discharged battery, or a dying battery unable to hold charge.

Regards.
Title: Re: Motor wont go to full speed
Post by: Aeroresurrect on July 18, 2016, 06:25:29 PM
Thank you everybody !
The general opinion is a bad Lipo ( although I observe this motor cut-out is happening even after I charge the old LiPo).
The LiPo is 7.4V 800 mAH came with the RTF plane. Regarding ESC and the BLDC motor details, I have not checked.
I'll try a new LiPo first and let you all know how I fare !!!
Title: Re: Motor wont go to full speed
Post by: K K Iyer on July 19, 2016, 08:17:01 PM
Quote from: Aeroresurrect on July 18, 2016, 06:25:29 PM
Thank you everybody !
I'll try a new LiPo first and let you all know how I fare !!!

How did you fare?
Title: Re: Motor wont go to full speed
Post by: Aeroresurrect on July 20, 2016, 09:59:22 AM
Thank you Mr Iyer,

Yet to procure a new LiPo.
Most sites showing out-of-stock !
Title: Re: Motor wont go to full speed
Post by: vibranthobbies on July 20, 2016, 10:58:35 AM
This Lipo may suit your requirement.
http://www.rchlipos.com/bonka-850mah-25c-2s-7-4v-lipo-battery.html
or
http://www.rchyper.com/bonka-850mah-25c-2s-7-4v-lipo-battery.html
Title: Re: Motor wont go to full speed
Post by: Aeroresurrect on December 08, 2017, 09:48:48 PM
Dear KK Iyer,

Sorry for the delayed response.

Your advice (and analysis of the malfunctions) was extremely accurate and precise (amongst many others who also suggested changing the Lipo).

With new Lipo, excellent performance ( I increased the Lipo size from 800 to 1500 mAH taking care of weight, CG etc).

Thank you so much.

Best wishes.
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