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Old 01-17-2012, 11:51 PM   #1
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Default Power Loss to ESC/Motor?

Ok, so my current VTA set up is a Savox 1258TG, LRP AI Pro Brushless Reverse ESC, Novak 25.5 motor, Gens Ace 5000mah 40c LiPo, and an Airtronics MX-Sport remote. I recently noticed an issue with this setup.

Whenever I allow the vehicle to drive without using the servo, the motor can spin up to full speed if I fully depress the throttle. Once I start steering back and forth left to right, the motor begins spinning considerably slower, and this is with equal throttle applied. If I steer back and forth quickly, the motor will slow down almost to a crawl. The servo will still go left and right, but the spinning of the motor is cut down at least 80%.

I've tried switching out servos and batteries, and trying them each individually on other cars. The problem still occurs. With the Savox 1251MG servo, the problem is still there, but it's significantly less than with the larger 1258TG.

I've also tried each servo with a Hobbywing 35a/13t motor set up, and the slowing down did not happen. However, I can't pinpoint exactly if its the ESC or the motor, and I'm hesitant to take it apart because I do not own a soldering iron, nor do I know how to solder anyway.

Anyone have a guess as to what the problem may be?
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Old 01-18-2012, 12:01 AM   #2
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Originally Posted by hyujmn View Post
Ok, so my current VTA set up is a Savox 1258TG, LRP AI Pro Brushless Reverse ESC, Novak 25.5 motor, Gens Ace 5000mah 40c LiPo, and an Airtronics MX-Sport remote. I recently noticed an issue with this setup.

Whenever I allow the vehicle to drive without using the servo, the motor can spin up to full speed if I fully depress the throttle. Once I start steering back and forth left to right, the motor begins spinning considerably slower, and this is with equal throttle applied. If I steer back and forth quickly, the motor will slow down almost to a crawl. The servo will still go left and right, but the spinning of the motor is cut down at least 80%.

I've tried switching out servos and batteries, and trying them each individually on other cars. The problem still occurs. With the Savox 1251MG servo, the problem is still there, but it's significantly less than with the larger 1258TG.

I've also tried each servo with a Hobbywing 35a/13t motor set up, and the slowing down did not happen. However, I can't pinpoint exactly if its the ESC or the motor, and I'm hesitant to take it apart because I do not own a soldering iron, nor do I know how to solder anyway.

Anyone have a guess as to what the problem may be?
My first thought is that you need to run a glitch buster capacitor on the receiver. I run an Airtronics M11 with a Spektrum module and I have a problem with the receiver cutting off if I don't run a capacitor. It is because the built in BEC in most speed controls is not powerful enough to power the Savox or other high speed digital servos without dropping power past the cutoff for a Spektrum Rx. I don't know what the symptoms of this issue would be on an Airtronics Rx. I have found the only ESC with a powerful enough BEC are the Speed Passion ESCs because they have a 3 amp BEC. Second thought is that you might be getting some binding in the drivetrain at full lock.
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Old 01-18-2012, 03:49 PM   #3
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Originally Posted by Fast04STi View Post
My first thought is that you need to run a glitch buster capacitor on the receiver. I run an Airtronics M11 with a Spektrum module and I have a problem with the receiver cutting off if I don't run a capacitor. It is because the built in BEC in most speed controls is not powerful enough to power the Savox or other high speed digital servos without dropping power past the cutoff for a Spektrum Rx. I don't know what the symptoms of this issue would be on an Airtronics Rx. I have found the only ESC with a powerful enough BEC are the Speed Passion ESCs because they have a 3 amp BEC. Second thought is that you might be getting some binding in the drivetrain at full lock.
Savox servos are power suckers from what I heard!!!
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Old 01-18-2012, 11:10 PM   #4
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Originally Posted by Fast04STi View Post
My first thought is that you need to run a glitch buster capacitor on the receiver. I run an Airtronics M11 with a Spektrum module and I have a problem with the receiver cutting off if I don't run a capacitor. It is because the built in BEC in most speed controls is not powerful enough to power the Savox or other high speed digital servos without dropping power past the cutoff for a Spektrum Rx. I don't know what the symptoms of this issue would be on an Airtronics Rx. I have found the only ESC with a powerful enough BEC are the Speed Passion ESCs because they have a 3 amp BEC. Second thought is that you might be getting some binding in the drivetrain at full lock.
That fixed it! Had a local guy look at it and he said the same thing. My brother had a spare Glitch Buster capacitor. Stuck that sucker on there and problem solved!

Thanks, guys.
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