Are motor cut-off brakes legally required?

[guerney]

Cutoffs are also meant to be a safety feature in the event of a throttle stuck open fault through rain ingress etc, although I imagine most people would have the braking strength to overcome the motor.

I guess it depends on how your bike is set up - I prefer assistance activating fast enough to make my bike easy to start pedalling, but not so fast I can't safely manage a U turn without needing to use the brake cutoffs too much (before firmware fiddling, it was all jumpy and lurchy). On precarious offroad parts and in chock a block slow moving stop/start traffic (my bike's usually too wide to filter, even with the Oxford sticking out from the right hand side handlebar-end and wing mirror folded in), brake cutoffs are essential for safety. The cadence sensing mid-motor driving my 20" wheels has a lot of torque, sometimes inches matter - it's well worth avoiding shooting a foot or so into space while on a narrow winding path along the edge a ravine for example. I am very rarely offroad, but when I am, every so often there's a ravine.

 

[Nealh]

The isssue with over coming stopping issues (due to an open /faulty throttle ) is one will burn the controller out and then be stuck with a heavy unpowered bike to ride.
For bikes that use decent controllers with no over run issues then it is quite simple, fitted throttle then use one brake sensor , no fitted throttle no brake sensor needed.

 

[guerney]

Tsdz2 doesn't need them , all my bikes that have used KT controllers again need no brake sensors. The only likely scenarion for them is if the need for throttle is fitted.

For bikes that use decnet controllers with no over run issues then it is quite simple, fitted throttle then use one brake sensor , no fitted throttle no brake sensor needed.

You've got a torque-sensing mid-drive which sips battery power, a totally different animal to my cadence-sensing battery guzzling mid-drive. I could make changes to my BBS01B's firmware parameters to render brake sensor cutoff unnecesary, use less battery power, but that would be at the expense of ease of pedalling, which I will not abide because I need to arrive at work completely sweat free and full of beans. Besides, the extra power is also useful for dragging heavy trailers up hills.

 

[saneagle]

although I imagine most people would have the braking strength to overcome the motor.

Or the intelligence to hit the OFF switch, or lift the wheel off the ground while you find the off switch. The worst thing you can do is hold the motor still with the brakes when it's powered. You might end up burning to death. The least you'd get is a blown controller and/or burnt motor.

 

[guerney]

Or the intelligence to hit the OFF switch, or lift the wheel off the ground while you find the off switch. The worst thing you can do is hold the motor still with the brakes when it's powered. You might end up burning to death. The least you'd get is a blown controller and/or burnt motor.

Blimey that's a bit dramatic! Memorable image too - the BBC would love it if ebikers went up in flames screaming while gripping their brakes and burning to death at traffic lights all over the country. It'd spawn yet more fluffy and largely useless puff pieces about ebike battery safety. Thank goodness I have brake sensor cutoffs.

 

[AntonyC]

I stand corrected! I'd assumed all controllers would behave like mine, detect a stalled motor and cut out (it's programmed to after a second, it's not due to overheating).

 

[saneagle]

I stand corrected! I'd assumed all controllers would behave like mine, detect a stalled motor and cut out (it's programmed to after a second, it's not due to overheating).

No, they don't cut out unless they have a temperature sensor, and, even then, the sensor temperature lags the MOSFET temperate, so they'd blow before the cut off. The controller should regulate the current, which seems to work with a running motor, but not a stalled one.

I've never blown anything myself like that because I haven'ttried it, but many years ago, we did have a couple of members that mentioned that their bike didn't work after holding the motor with the brake because the throttle broke, and both turned out to be blown MOSFETs. If you want to be sure, you'd have to try it and see what happens. Make sure you do it outside and have a fire extinguisher to hand, just in case.

 

[AntonyC]

Of course, the Lithium extinguisher's in the pannier, wrapped in the glassfibre blanket.

That's just weird though isn't it? Speed sensor idle > 0.5s => cut out, what have I missed? Maybe the flimsy battery extension has saved my controller by restricting phase current, it's certainly survived a few abuses while shunting on our steep driveway.

 

[Bonzo Banana]

I think there are lots of approaches to this problem including of course not having braking sensors. You could consider changing your hydraulic brakes to those with cut off sensors built in. This sort of thing;

GUSTAVO E-bike Brake Hydraulic Disc Cut Off Power Brake SM /2PIN Waterproof Plug Ebike Scooter Front Rear Brakes - AliExpress 18

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

You could fit mechanical disc brakes with levers with cut off sensors but maximise braking performance with that design by making sure your brake mechanisms are dual piston not single piston like many budget mechanical disc brakes supplied with budget bikes and fit larger rotors like 180mm or 203mm.

You could put a separate switch assembly on the handlebars with a on/off or momentary cut off switch close to the brake lever and connect this to the brake cut off line of the controller so you have an emergency switch to use in case you have a controller where there is a bit of run on when you stop peddling or as a safeguard to a faulty throttle.

While not neat you could go with a rear hydraulic disc brake without sensor and a front mechanical disc brake with cut-off. No one wants to fly through the air arse over tit so maybe its not a bad idea to have a weaker front brake compared to the rear where most of the weight is and you have better traction. If you have a cluttered cockpit anyway its not the end of the world to have two different brake lever designs.

I must admit I bought some of the Chain Reaction clearout stock of Clarkes Clout front hydraulic disc brake kit with 180mm rotors which were about £8 previously. I think it cost me £24 for 3 sets minus a bit of topcashback. There was a discount code I could use at the time which bought the price down from £8.99. I believe I can re-configure them as rear brakes by using a different mounting bracket from a rear brake and lengthening the cable and I personally don't mind which brake lever operates which brake mechanism, if I stay UK style or change to European style it doesn't matter to me. So that would be an option for me but realise many wouldn't want to replace the cable on a hydraulic disc brake and of course while the mechanisms may be usable front or back I think, the brake levers can't so I will doing what I suggest above and using a V or mechanical disc brake for the front to get the cheapskate compromise I suggested above.

 

[thelarkbox]

? just use one of the sensors for the hydraulic brakes just not on the brake, glue a loop to a rare earth magnet, secure the sensor behind some steel in an accessible position and stick the magnet atop it.

Use the loop and yank off the magnet in an emergency, and it will also serve as an added security device disabling the engine without the magnet in place when parked etc.

 

[Nealh]

Another thread where users make a mountain out of mole hill for a function that has little use unless a throttle is fitted.

 

[guerney]

Another thread where users make a mountain out of mole hill for a function that has little use unless a throttle is fitted.

For my bike at least, that's not true. Your experience with your bikes and firmware settings may differ.

 

[saneagle]

I think there are lots of approaches to this problem including of course not having braking sensors. You could consider changing your hydraulic brakes to those with cut off sensors built in. This sort of thing;

GUSTAVO E-bike Brake Hydraulic Disc Cut Off Power Brake SM /2PIN Waterproof Plug Ebike Scooter Front Rear Brakes - AliExpress 18

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

You could fit mechanical disc brakes with levers with cut off sensors but maximise braking performance with that design by making sure your brake mechanisms are dual piston not single piston like many budget mechanical disc brakes supplied with budget bikes and fit larger rotors like 180mm or 203mm.

You could put a separate switch assembly on the handlebars with a on/off or momentary cut off switch close to the brake lever and connect this to the brake cut off line of the controller so you have an emergency switch to use in case you have a controller where there is a bit of run on when you stop peddling or as a safeguard to a faulty throttle.

While not neat you could go with a rear hydraulic disc brake without sensor and a front mechanical disc brake with cut-off. No one wants to fly through the air arse over tit so maybe its not a bad idea to have a weaker front brake compared to the rear where most of the weight is and you have better traction. If you have a cluttered cockpit anyway its not the end of the world to have two different brake lever designs.

I must admit I bought some of the Chain Reaction clearout stock of Clarkes Clout front hydraulic disc brake kit with 180mm rotors which were about £8 previously. I think it cost me £24 for 3 sets minus a bit of topcashback. There was a discount code I could use at the time which bought the price down from £8.99. I believe I can re-configure them as rear brakes by using a different mounting bracket from a rear brake and lengthening the cable and I personally don't mind which brake lever operates which brake mechanism, if I stay UK style or change to European style it doesn't matter to me. So that would be an option for me but realise many wouldn't want to replace the cable on a hydraulic disc brake and of course while the mechanisms may be usable front or back I think, the brake levers can't so I will doing what I suggest above and using a V or mechanical disc brake for the front to get the cheapskate compromise I suggested above.

That listing shows as not delivered to UK, but if you do a Google search, you can find other Aliexpress listings that do with free shipping for around £20 including tax. Sounds like a bargain to me. I ordered some to test because that would make a very cheap conversion for anyone with cable disc brakes.

GUSTAVO E-bike Brakes Disc Hydraulic Brake SM / 2PIN Plug Electric Scooter Folding Mountain Bike Power Off - AliExpress 18

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

 

[Nealh]

For my bike at least, that's not true. Your experience with your bikes and firmware settings may differ.

Difference is you are tweaking your parameters for a motorbike like power option with full throttle rather then standard eapc options.
With KT controllers one can't change the settings much, yes one can adjust parameters but unless one uses OSF for KT controllers there are no real option to change any thing.

 

[guerney]

Difference is you are tweaking your parameters for a motorbike like power option with full throttle rather then standard eapc options.

Within the rules. You made an incorrect sweeping statement:

Another thread where users make a mountain out of mole hill for a function that has little use unless a throttle is fitted.

Pedal assistance started while I was pushing my bike through long grass once... long grass turned the folded pedals, cadence sensing motor switched on, and the bike reared up like a wild horse. I was grateful for brake cutoffs then, I can tell you. It might have escaped. These days, I switch the battery off first.

Difference is you are tweaking your parameters for a motorbike like power option with full throttle rather then standard eapc options.

I don't have a throttle. My 36V motor is rated 250W. Speed is limited to 25Km/h. "250W" is engraved by the manufactuer on my BBS01B. "250W" is also stated on my receipt.

It's weird that a dude who has a 500W rated Bafang CST on his bike keeps going on about illegal ebikes. Sure, you don't shout about it (understandably), but you still have and use one. Illegally. Unless you bought your TSDZ2 from Woosh - you didn't - I doubt it's legally rated by the manufacturer and labelled 250W. Pot meet kettle.

 

[guerney]

I prefer to be seen pedalling... I'm not actually making much effort doing so, but if I really wanted to extract the widdle, I'd set motor run on in firmware very long (instead of short), set controller amp limit at 20A (instead of 18A)... then pedal a bit so the bike shoots to 15.5mph, pedal every so often when assistance finally tails off. Sure, this would be tough on the controller, but I imagine it'd be a wonderful setup for very elderly or ill folk to enjoy riding a bike amost completely effort free - this wouldn't be safe without ebrakes however, and it'd be best done on a small wheeled robust framed folding bike BBS01B conversion, so that when the controller fails the bike can be folded into a bus, train or taxi, also because there's more torque with the mid-motor driving a small wheel. As far as I can discern, BBS01B controllers are much longer lived than BBS01 controllers were.

 

[Nealh]

One advantage of any KT system , it has a zero assist setting so PAS actuation couldn't occur.

 

[guerney]

One advantage of any KT system , it has a zero assist setting so PAS actuation couldn't occur.

That's possible with the BBS01B too (see my Level 0 below), but it's quicker to turn the battery off.

 

[RollingChunder]

No one wants to fly through the air arse over tit so maybe its not a bad idea to have a weaker front brake compared to the rear where most of the weight is and you have better traction.

Only true when the bike is stationary/accelerating. When braking, most if not all (a stoppie) weight is on the front wheel. Put your best braking system on the front if you have to choose.

 

[saneagle]

That's possible with the BBS01B too (see my Level 0 below), but it's quicker to turn the battery off.


View attachment 56334

That's too many levels. Three should be enough plus one for zero assist. If you actually use nine levels, you'd be constantly pushing the buttons up and down, which would soon wear them out.