Weird grinding noise when using electric motor brake

[metinoheat]

Hey guys, first time poster here. Im in the process of building an E-MTB (thanks to the tutorial on this site) and i am wondering about something.

My board is mostly set up and it rides very well but the brakes sound more like breaks if you know what i mean. Every time i engage the electric brake, it sounds like some kind of grinding noise within the motor. i have posted a vid me riding it at work. you can hear it very well at 23 seconds in.

http://youtu.be/sWm7iXzdkRM

Does anyone know if this is the normal braking noise? I dont mind it so much as i want to make sure im not destroying my motor!

Thanks

p.s. the build specs are as follows

120a FVT car esc
245kv Tacon Bigfoot brushless motor
2x 4s 5ah lipos
vintage earthboard (style points?) mtb

 

[psychotiller]

Electric "braking" on our boards definitely make a noticeable sound. Some a little louder than others. Don't be too alarmed. You can adjust the braking percentage and it'll help a little. I run most of my boards between 50 and 70 percent.

 

[made_in_the_alps_legacy]

you run at 4s with 245kV motors ?
on mine it's more a tone than a grinding sound... maybe because it has higher voltage and lower kV compared to yours

 

[metinoheat]

Well I guess it's good to know that I'm not damaging it, but is there anything I can do to lessen the noise? Perhaps a lower kv motor?

 

[psychotiller]

Try running 6s and lowering your brake percentage. (unless you're running your batteries in series already @8s...not sure if your esc will like that though)

 

[Hummina Shadeeba]

I watched ur video and a video says a thousand words. I have the tacon160 with 4s on my board I ran, which has a video with brakes applied, on here. If u look at my in da hub motor mount thread you'll hear it. Much different sound. I find the search function here doesn't work spactacularly( don't want to disparage this site!). So same motor and hobbywing150 esc ( is that the issue, the esc? I've been wanting a quieter esc myself and asking on here. I'd imagine the esc is the difference because my esc sounds much different. But, as everyone here says the settings...I wish I'd spent ten bucks for the programming card as I could NOT get it to do what I wanted.
I do not ride an electric board. I would rather not work it seems than save the bucks for the multiple parts I keep destroying. I feel I need to present myself fully.

I wonder