No more braking downhill

1

Hi,
Is it possible that when my motor exeeds its max rpm it wont brake anymore? Because i was going downhill and i couldnt brake anymore so i had to jump of my board and fall against a fence.
Luckily i fell good, and only broke my thumb probably, but I wonder why i couldnt brake anymore

I have to say I did it on a single drive board, which is not the smartest idea ever.

My setup (now) :
Single flipsky 6354
12t 36t, so low low top speed (new pulleys incoming and motor for dual drive)
Max regen 10amps
Single fsesc 4.12
97mm wheels

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2

That’s what you consider lucky? The question is what was the charge of your battery, just how much did you exceed erpm by, and what type of BMS does your battery have?

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3

Right, battery was quite full 100 percent when i started, first 2km to the mountain, than up the mountain which my board could just do but had little struggle, i have 10s4p, only charge bms, i have no idea how much i exceeded erpm, i was going (estimated) 40kmh or something, whule my top speed is around 35kmh

4

Im lucky i guess yeah, could have gone way worse, i am all good except my thumb, and even that pain os bareable so, I consider myself lucky yeah😅

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5

Well charge only BMS rules out BMS cut… Any chance you exceeded max voltage? I’m assuming you didn’t run for faults on the ESC after the incident… Is the board functioning properly atm?

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6

Yeah board is doing all fine, pulls the same, same top, braking is good, can I still check for faults? Or does it save that really temporarily

7

It’s gone if the esc loses power, have to keep the board on to run faults… Idk, given your speed it sounds unlikely you exceeded max erpm, I suspect overvoltage from regen braking but I can’t think of a way to test…

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8

Hm… Sure? I mean, when i go 35 the motor just stops pulling even though it gets there eaaasy, so i thought that would be the max rpm the motor can handle, but not sure.
But next time i wont go with a completely charged battery and see if it helpt😅 and try to test it in a safe environment where theres no corners after a long slope lol
Thanks for the replies by the way

9

Nah he’s saying he doesn’t think it is a max erpm issue.

It sounds like your brakes might have tried to charge your battery a bit too much or too quickly and got something shut down.

I’d imagine you’d have used plenty of battery getting up the hill to have room to regen on the way down…

Usually loss of brakes happens when you’re fully charged and go downhill.

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10

Could be, maybe full braking was too much for the motor or esc, i hope when i go dual drive it won’t happen again

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11

What’s was your regen set at in amps?

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12

10amps

13

Yeah that’s not extreme or anything. Maybe it was so low of a regen that it felt like no brakes? Dual drive will definitely help as you can pull double the braking amps.

Good luck and be safe testing!

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14

Yes maybe, it felt like it was doing something but i dont recall that well it all went pretty fast when i realised i was going to crash
I will definitely be safe testing, dont want this to happen again ;p
Also maybe the wheel could have locked up , i have that sometimes while braking, that doest work well.
But we’ll see if I ever encouter this problem again in a safe environment maybe I can see what it is

Thanks for the replys and ride safely boys!

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15

10 amps? That’s not going to do anything

For example. I have 60 amps and sometimes that’s not enough to slow down when going 30 mph downhill in less then 15 seconds

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16

Yeah I thought 10amps would have been a bit low, but aint 60 a little high!?
I was thinking bumping it up to 15 for now, and when i go dual 10 per motor…?

17

I was with this man, i had to bail off that thing even before him xD. I think the brake just wasn’t strong enough to stop accelerating.
Weird thing is that i run about -14 amps divided over two motors and it held fine, which isn’t that much more.

Also my pulleys are 15t instead of 12, which would result in worse braking

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18

My board is just a suicidal piece of wood i guess

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19

Well there’s a difference between motor - and battery amps though. Do you really have your battery regen amps at 60? That’s crazy

10 amps isn’t that low, for a single, sure but on my board I have -12 on each of my two vescs and I can stop on hills.

Yeah this is what I’m talking about haha

20

I run 70A regen for 10s4p 30q battery. Single flipky vesc 6.6, single 6374 motor, 2WD. Can block wheels while braking with this setup.