HPI SC-15WP power surge problem

[EasonsWraith]

Hey everyone. I have a SC-15WP esc in my Axial Wraith. I recently swapped the stock motor for a Axial 35t. Since the upgrade a throttle surge has started happening under low throttle. While lightly engaing the throttle it jumps ahead and repeats.

Any help would be appreciated.


Thanks

[HumboldtEF]

Isn't that a short course ESC?

Some ESC's just dont do low speed control well. That my guess, I've seen crummy RTR ESC's do this where they just cant stay at a constant low speed without stopping but with a little more throttle will drive normal, still crummy but normal. Maybe this new motor isnt as good at low speed control either, Stock Axial motors have never been all that amazing.

Does it drive normal after you give it a bit more throttle?

If low speed control is important you'll probably want a Crawler specific ESC ANd possibly a nicer motor. Holmes Hobbies has some great budget motor options now.

[EasonsWraith]

Oh I did not realize it was short course ESC, it was in my Wraith when I bought it 2nd hand. I have been upgrading to be more Crawler specific.

It does smoothen out when given more throttle. Does the ESC need to be recalibrated perhaps?

Thanks for your help

[durok]

I'd be looking for a HobbyWing 1080 ESC to replace what you have - they run about $43 on eBay, come with a programming box and are excellent waterproof brushed crawler speed controls.

They handle 3S LiPo easily and have a pretty strong BEC so for most servos you don't even need to pick an external one.

[lonleycreeper]

Originally Posted by EasonsWraith

Oh I did not realize it was short course ESC, it was in my Wraith when I bought it 2nd hand. I have been upgrading to be more Crawler specific.

It does smoothen out when given more throttle. Does the ESC need to be recalibrated perhaps?

Thanks for your help

I had a couple of those and they are rather terrible, esp on 3s. The Hobbywing 1080 is leaps ahead in smooth performance.

[EasonsWraith]

Ok thanks for the advice guys. I should also mention, I did have some trouble with my Servo a little while back. The red wire was binding up on the frame as the shock compressed. It made a crack very close to the servo housing. I do believe the wire got wet as the truck glitched out and went full throttle, full turn into my car. I then cut the wires, reconnected and heat shrinked then used a small amount of waterproof silicone to reseal the outside of the servo.
Would this have any anything to do with the power surge? Sorry I didn't mention previous as I assumed this wouldn't affect the ESC.

[HumboldtEF]

Originally Posted by EasonsWraith

Ok thanks for the advice guys. I should also mention, I did have some trouble with my Servo a little while back. The red wire was binding up on the frame as the shock compressed. It made a crack very close to the servo housing. I do believe the wire got wet as the truck glitched out and went full throttle, full turn into my car. I then cut the wires, reconnected and heat shrinked then used a small amount of waterproof silicone to reseal the outside of the servo.
Would this have any anything to do with the power surge? Sorry I didn't mention previous as I assumed this wouldn't affect the ESC.

Its possible the servo is playing a role here. When they go bad some servos can back feed voltage to the ESC and generally do odd stuff. You could disconnect the servo from the receiver and re-test it to see how smooth the start up is. If that clears things up you'll know that was the cause. Or if you have another known good servo to test with you could just plug it into the receiver (no need to install it on the rig though) and test the start up.

[EasonsWraith]

Oh ok that makes sense. I will try that first.

Thanks for your help

[EasonsWraith]

It is still acting the same, no change. I guess the ESC can be the only other problem?

[HumboldtEF]

Thats my guess. Though it may be the combination of that specific motor and the ESC combo. If it were me I'd probably upgrade both but I dont want to make you spend money if you dont want to.
What motor did it have before this recent change?

I'd consider a HW 1080 and a Holmes Hobbies Crawlmaster sport, if your wraith is the 2.2" tire version consider a 550 size motor (though I think the skid needs to be modified to accept a longer can) 540 size should be okay for the 1.9" wraith.

[EasonsWraith]

The previous motor was the Titan Monster 550.
The surge problem started before I changed to the new Axial 35T motor.

Thanks