Help me not die, brakes suck.

[Alpacaslapper]

I’m fighting a problem breaking, here’s the down low; I can break slowly, but if I need to brake aggressively I get what I think is cogging. Originally I thought it was belt slipping so I added a tensioner pulley. Also when I’m almost stopped the brakes let go and I free roll at slow speed.

Motor max 60a
Motor min -60a
Battery max 30a
Battery min -30a

Battery is 10s1p qb26800, I don’t care about prolonging the battery life, I care about prolonging my life.

Motor is a keda 6364 190kv

Fs vesc 4.12 fw 5.1

15/32 gearing

80mm cags

Where should I look?

[cfelzien]

Battery max brake… I think

[Linny]

Change motor min to -80.

[Alpacaslapper]

Ok I’ll give -80 try after work. Im also going to mark the belt on both pulleys to verify it’s not still slipping

[b264]

It probably belt skipping. What control mode is it set to? FOC unsensored?

[Alpacaslapper]

Bldc no sensors

[OleksiiF]

Does this battery can handle 30a charge and 60a discharge? Btw, its about prolonging your live as well as batteries life

[b264]

Sounds like belt skipping then

[Alpacaslapper]

@OleksiiF

Does this battery can handle 30a charge?

Short answer, no, but I’d rather have brakes when I need them.

[BornBoneless]

+1 for belt skipping.

What size belt are you running?

[OleksiiF]

Dont use such settings so, its damn how unsafe. And for discharge can it handle 60a?

[Alpacaslapper]

10mm

[Alpacaslapper]

The batter is not discharging 60 amps, battery max set to 30.

[ProfoundMagician]

Is that 3d printed mount?

[Alpacaslapper]

Correct, but these symptoms I’ve have on a dickyho aluminum mount as well.

[b264]

Definitely belt skipping. Try a 15mm wide belt and carefully align it.

@b264

Without going into tensioning, which is king, I would say check the alignment very carefully. A belt that’s not aligned well can slip, as @taz mentioned.

Something else that can cause anywhere from minor to massive slipping in a perfectly aligned and tensioned belt, is broken cords. If your belt has broken cords inside, you will typically not see any indication of this by inspecting it (sometimes you can though) but it will just skip like crazy. In that case, failure is imminent anyway and you need to replace it before many more rides. If you check multiple belts, some new, and the skipping persists…

Then check when the skipping is happening. If the worst skipping is happening any other time besides during hard braking, then I don’t know what’s going on. That’s always when the worst skipping happens.

Alignment – the best way I’ve found to perfectly align belts is

• get motor mount (without motor) snug on hanger, then loosen a tiny bit so it moves
• install wheel and pulley with no speedring (washer) between the hanger and inner bearing.
• push motor mount flush up against wheel pulley so they are touching each other
• keep those held tightly together while you tighten motor mount clamps
• make sure mount is flush against, and touching, the wheel pulley, and there is no gap or misalignment
• finish tightening mount clamp all the way
• make sure again that mount is flush against, and touching, the wheel pulley, and there is no gap or misalignment
• when you’re all done, take the wheel and pulley back off, add a single 1mm speedring (washer) and just like that, the pulley will be perfectly aligned and 1mm away from the motor mount plate
• if you need it further away when you are doing tensioning, then add more washers

And also make sure your pulleys are concentric and don’t wobble at all as @taz mentioned. That’s super important.

[Alpacaslapper]

@b264

Definitely belt skipping. Try a 15mm wide belt and carefully align it.

@b264

Without going into tensioning, which is king, I would say check the alignment very carefully. A belt that’s not aligned well can slip, as @taz mentioned.

Something else that can cause anywhere from minor to massive slipping in a perfectly aligned and tensioned belt, is broken cords. If your belt has broken cords inside, you will typically not see any indication of this by inspecting it (sometimes you can though) but it will just skip like crazy. In that case, failure is imminent anyway and you need to replace it before many more rides. If you check multiple belts, some new, and the skipping persists…

Then check when the skipping is happening. If the worst skipping is happening any other time besides during hard braking, then I don’t know what’s going on. That’s always when the worst skipping happens.

Alignment – the best way I’ve found to perfectly align belts is

• get motor mount (without motor) snug on hanger, then loosen a tiny bit so it moves
• install wheel and pulley with no speedring (washer) between the hanger and inner bearing.
• push motor mount flush up against wheel pulley so they are touching each other
• keep those held tightly together while you tighten motor mount clamps
• make sure mount is flush against, and touching, the wheel pulley, and there is no gap or misalignment
• finish tightening mount clamp all the way
• make sure again that mount is flush against, and touching, the wheel pulley, and there is no gap or misalignment
• when you’re all done, take the wheel and pulley back off, add a single 1mm speedring (washer) and just like that, the pulley will be perfectly aligned and 1mm away from the motor mount plate
• if you need it further away when you are doing tensioning, then add more washers

And also make sure your pulleys are concentric and don’t wobble at all as @taz mentioned. That’s super important.

I followed these exact instructions for alignment.

Are there tensioning instructions?

I will order a 15mm belt today.

[Alpacaslapper]

I have so many teeth engaged on the pulley Im shocked if it’s still slipping, but I will mark and test.

[b264]

@Alpacaslapper

Are there tensioning instructions?

Tensioning is kind-of an art form.

My advice is make it as tight as reasonably/easily possible with just your fingers, without using tools to pry on it, and when you pinch the belt around the motor pulley with your fingers it should squeeze about 5mm or so.

There are also tensioning methods that involve plucking the belt with a hex key and using a guitar tuner to tune the belt pitch, but I don’t recommend that. If you do that, maybe 150Hz.

And all my advice is for no idler pulley. I don’t use them anymore… though it does look like you’ve installed it on the correct side. Be 100% sure the idler pulley can’t wiggle.

Hold the motor can and try to force the wheel to spin the same direction it’d be spinning during braking.

[Alpacaslapper]

Tensioner is rock solid, I’ll have to measure the belt and get a shorter one to use this mount without it.

Squeezed

Relaxed

Too loose?