Are ebrakes sufficient?

I see on this kit there are ebrakes. Are these sufficient to quickly stop my ride? If not I don't know how I would activate both my side pull brakes and ebrakes at the same time. Maybe they're intended for coaster brakes...

https://www.aliexpress.com/item/36V-250W-350W-500W-Kettle-Battery-Ebike-Kits-Electric-Bike-Conversion-Kit-With-LED-Display-LCD/32732465200.html?spm=2114.search0104.3.31.19552a014V77Im&ws_ab_test=searchweb0_0,searchweb201602_4_10152_10151_10065_10344_10130_10068_10324_10342_10547_10325_10546_10343_10340_10548_10341_10545_10696_10084_10083_10618_10307_10313_10059_10534_100031_10103_10624_10623_10622_10621_10620_10810_10811,searchweb201603_1,ppcSwitch_3&algo_expid=ad911417-6060-4284-8046-b70e640c5038-4&algo_pvid=ad911417-6060-4284-8046-b70e640c5038&transAbTest=ae803_4&priceBeautifyAB=0

You're supposed to swap your normal brakes, with these ones.
So, when you brake, they also cut the power from the motor.
Not 100% essential IMO.

Right so are these sufficient to quickly stop my ride?

They are as sufficient as your normal brakes. They wont brake your bike better. They are just new brake levers that control your bikes brakes, but they have the extra feature of killing the motor when you use them.

I have never used ebrake levers.
Its a safety feature on the levers, as mentioned

Direct drive motors using regen, saves a lot of brake pads and helps stopping but is no replacement for decent brakes, whether they are rim V-brakes or disc brakes

My next "cheap" controller is going to be from Greentime, a 24fet with regen.

you cannot replace brakes with Ebrakes. You still need some sort of mechanical or hydraulic brake system to stop the bike fast when say for instance the battery on the bike dies...then you will have no Ebrakes...or if you go down a big hill and a need to stop

skeetab5780 said:

you cannot replace brakes with Ebrakes. You still need some sort of mechanical or hydraulic brake system to stop the bike fast when say for instance the battery on the bike dies...then you will have no Ebrakes...or if you go down a big hill and a need to stop

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I was thinking that. Unless the controller does some sort of reverse current when the brake lever is pulled to actively resist the forward speed, I couldn't see how it could possibly stop the bike. So I guess because you must still retain standard levers that many people such as markz do not use ebrakes.

There's a lack of precision when most folks say "e-brakes" because some mean power cutoff switches, others mean regenerative braking, and others mean active electrical braking.

The first is not a bad safety feature, but totally optional-- and it isn't a brake. The second is useful in some cases, but no substitute for mechanical brakes. The third is potentially a substitute for rear brakes, but not common at all.

Ditto to what Chalo said, but with a caveat: Most of these systems do not have any modulation; they're either on or off. You're either braking at full strength or not braking at all.

There are beginning to be more generic controllers taht support variable, or proportional, regen. Haven't seen any generics taht support v/p EABS, though some higher end and some DIY controllers do.

Another caveat is that Regen tends to work better the emptier the battery is, while EABS works better the fuller it is.

One more caveat is that either of these only works with DD (direct drive) hubmotors in a wheel. All the other types of motor systems generally have a freewheel or slip-clutch of some type between the wheel and the motor, so the motor can only create forward motion, not stop it or slow it or create reverse motion. (there are exceptions, but not many).

Also, just because a controller says it has EABS, or regen, doesn't mean it's actually quite what is commonly known as those, or that it's of a useful strength. :/


I have both the second and third options in Chalo's list on SB Cruiser, the second on the rigth side, usually called Regen, and the third on the left, sometimes called EABS.

I think on a more typical bike with a medium rider, say 200lbs total, the EABS might be able to stop it in it's own length, and/or skid the wheel. On SB Cruiser (more than twice that weight, with me on it), by itself, it'll stop the trike in a few trike lengths from 20MPH (at one point it would do it in just over it's own length, but it changed on it's own at some point and I've been unable to determine why; it's not a programmable controller).

The regen by itself would slow the trike significantly, but could not stop it, as it only works down to a few MPH, rather than to essentially zero like the EABS.

Together, they will stop the trike in a couple of trike lengths or so, maybe a bit more.

But I still have a front mechanical brake that can stop the trike on it's own, too.

vagosofron said:

Not 100% essential IMO.

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Anyone who thinks ebrake cutoff switches of some sort (whether they activate regen or just cut motor power) aren't essential is foolish, and should without question not pass that advice along to others. It is an essential safety feature of any ebike, because it's there to stop runaway conditions in the event of a throttle failure, and with the $1-2 cost (regardless of price paid) of typical ebike throttles, failures are quite common especially when ridden in the rain. Don't rely on having to let go of the handlebar with one hand to reach for another cutoff switch in the event of a runaway throttle condition when just grabbing a brake handle is so instinctive and easy.

As others have said, it doesn't replace the need for mechanical brakes, but regen braking does recover so otherwise wasted energy and it drastically reduces brake maintenance. I went from replacing front brake pads every 4-6 weeks to less than once a year. Plus depending how I rode I could get 5-25% extra range from a charge using regen.

John in CR said:

Anyone who thinks ebrake cutoff switches of some sort (whether they activate regen or just cut motor power) is foolish, and should without question not pass that advice along to others. It is an essential safety feature of any ebike, because it's there to stop runaway conditions in the event of a throttle failure,

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That sounds like motorcycle advice, not bicycle advice. I've never had a single mechanical brake that couldn't shut down my leg power and motor power combined. And my leg power exceeds almost anybody's.

John in CR said:

vagosofron said:

Not 100% essential IMO.

Click to expand...

Anyone who thinks ebrake cutoff switches of some sort (whether they activate regen or just cut motor power) is foolish, and should without question not pass that advice along to others.

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I never adviced people not to use ebrakes. I simple wrote, in my opinion that they are not 100% essential. I am not a fool when it comes to safety.

I read somewhere awhile ago some respectable member saying there are some controllers that will have a circuit in the controller to "brake" the motor. Uses up battery power.

This is discussed above, here in this thread,
https://endless-sphere.com/forums/viewtopic.php?p=1368152#p1367896
and mentioned in Chalo's and Cdevidal's posts before that.

A primary reason for ebrakes is that they are a critical part of controller functionality where the controller, not the operator, directly controls and applies power - specifically autocruise and PAS. In both these cases ebrakes provide the only direct means to stop motor power in a timely or safe fashion.

I believe that you find that any regulation that requires PAS for bike operation also demands ebrakes simply because it is obviously dangerous to have a powered vehicle that continues to apply power on its own even though the operator is trying to stop it by applying the brakes. Since a large part of the ebike world suffers from PAS regulations, the widespread use of ebrakes is unsurprising. It is certainly easy to lose sight of that here in the US.

Ebrakes serve no such specific control function on throttle-only bikes. They have value there as a poor man's kill switch but otherwise offer no critical control function. In the throttle-only crowd their use certainly may bring up thoughts of assistance for those with poor hand coordination or who would probably drive an automatic using both feet...

Now only poor people should have ebrake cutoffs if they have speed control only by a throttle.

Why do you guys think that every controller made has wiring for ebrake cutoff? It's a damn good idea, and so easy. Anyone promoting otherwise isn't thinking through enough potential possible circumstances.

Chalo, enough with this motorcycle crap. Anything with 2 wheels is commonly called a "bike" to hundreds of millions of people across the world. If where you live there's sufficient infrastructure to ride safely at pedal bike speeds, that's great, but that's not everywhere, and probably doesn't include a majority of locations. Your answer to everything is more laws, regulations, and enforcement, which is an approach that I disagree with at a cellular level. I'm a courteous and conscientious ambassador to the cause and promote electrics by demonstrating what's possible, so please stop belittling my freedoms. BTW, if nothing else (and there's plenty of "else") think of the potential harm to your electric drive system if you force it to stop in a runaway condition using only mechanical brakes.

Don't confuse safety advantage with necessity for control - which is the point I made regarding PAS and autocruise. Those systems use ebrakes as the mechanism to disengage automatic motor control and so ebrakes are an integral part of the system operation - to turn it off. Conversely, there is no functional *need* for ebrakes on a throttle-only system. This is a technical issue.

There is no question that there is a safety advantage to ebrakes, but there are many folks - particularly those who ride motorcycles - who don't use PAS/autocruise and see no reason to have ebrakes - the technical need just isn't in their experience. A hundred years of motorcycles without a brake/throttle interlock for 'Safety' does little to change that view. Saying you don't *need* ebrakes is no different than choosing to ride a chopper with no front brakes. That's a personal choice and has nothing to do with safety or how poor you are - it has everything to do with how you prefer to ride.

Personally, I won't build a bike without a kill switch that can be flipped without releasing the grips. That's a safety feature that goes far beyond what brake cutouts afford at a fraction of the price. That said, it's not *needed* which is an entirely different concept.

John in CR said:

Chalo, enough with this motorcycle crap. Anything with 2 wheels is commonly called a "bike" to hundreds of millions of people across the world.

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My point was only that at bicycle power levels, a fail-on throttle condition can easily be stopped with one normal brake and the battery disconnected with the free hand. If the motor force exceeds the braking force (as might be the case with a motorcycle), it's not as straightforward, and electronic safely interlocks become more important.

Neither do I belittle your freedoms, such as they are. I only recognize that allowing people to use motor vehicles almost everywhere has ruined every major city in the world, and imposed upon us the single largest preventable cause of death and serious injury. I believe freedom from those things is much more important than the freedom to go really fast and inflict the consequences on others.

Even with a standard ebike that is within US Federal regulations, the ebrake (brake cutoff) serves several important safety purposes, and is required by that Federal regulation that defines an electric bicycle with regard to commerce.

One is when you have the bicycle energized but your not sitting on the seat. This occurs in many different situations, even including at a stop sign when you might put your foot down and shift your weight so it is not on the bike. It occurs when the bike is being manuevered at the beginning and end of a ride, or when walking the bike for any reason. A minor touch of the throttle will accelerate the unladen ebike with amazing performance, most everyone with much experience has noticed this, and many tell of rubber tire marks on the wall or ceiling of their house, garage or workplace from the unexpected reaction. The ebrake is very effective at controlling this, whereas the friction brakes are not very effective and take too long. Most people will grab the brake levers and they may not release the throttle. Sometimes the motion of the bike causes the throttle to be increased in this situation. The brake cutoff saves the day.

Another is when someone unfamiliar with the ebike rides it. Releasing the throttle in a panic situation is a learned reaction, and even experienced persons may find they have not learned this well enough. Grabbing the brakes is automatic, for most, and can be important to the safety of the moment. In some situations only a few feet spells the difference between being embarrassed and being crushed underneath a big tire.

I think brake cutoff switches are a really good idea on all ebikes, as are kill switches (as required on all motorcycles). The kill switch can be used to disable the power in many situations where it is not desirable to turn the motor system completely off, or inconvenient to do so.

None of this has anything to do with electric braking, the topic of the thread. Good electric braking is variable and goes beyond regen into reverse power when the speed is too low for regen to provide adequate braking force. It is a wonderful tool to have, however it is not sufficient to replace friction brakes. I have one ebike that has it on the rear hubmotor, and it feels like a parachute that I can modulate. It works great, even on 15% downhills. But on the front wheel I have dual 200mm discs. They aren't needed much but they must be there. I find I must use them hard from time to time to prevent loss of braking efficiency, keeping the surfaces conditioned.

Electric braking consumes very little power. At high speed regen is sufficient to provide strong braking force, in this region power is generated rather than consumed. At low speeds the regen is insufficient to provide good braking force as the back EMF (motor/generator voltage) is too low to drive adequate current through the motor. In this case the controller applies some power to maintain the braking effect. In this situation the low motor voltage allows motor current to be considerably higher than battery current, hence little power is consumed to create strong braking. The gain in motor current compared to battery current can be 3x to 5x or even 10x depending on the setup. So one amp from the battery can produce 3 to 10 amps in the motor. This does not last long, so the power actually consumed is usually less than was developed during regen earlier. It starts at low speed and goes to lower speed, and is a function of how hard the braking requested is. Gentle braking will produce very minimal consumption. Hard braking will increase the consumption, but reduce the duration. It is not a factor in range.

Chalo said:

John in CR said:

Chalo, enough with this motorcycle crap. Anything with 2 wheels is commonly called a "bike" to hundreds of millions of people across the world.

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My point was only that at bicycle power levels, a fail-on throttle condition can easily be stopped with one normal brake and the battery disconnected with the free hand. If the motor force exceeds the braking force (as might be the case with a motorcycle), it's not as straightforward, and electronic safely interlocks become more important.

Neither do I belittle your freedoms, such as they are. I only recognize that allowing people to use motor vehicles almost everywhere has ruined every major city in the world, and imposed upon us the single largest preventable cause of death and serious injury. I believe freedom from those things is much more important than the freedom to go really fast and inflict the consequences on others.

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Power is torque times rpm, so it's perfectly reasonable to build a climb anything very slow ebike that's 100% legal in any jurisdiction. In fact, it wouldn't have to be slow. eg If I was forced to live under the 750W power limit rule, then I would want to build a bike that had 750W of output at the wheel from 1rpm up the 30mph or so that I could get out of it, and they're likely be no way any bicycle brakes could stop such low speed torque.

Failures tend to occur at the most inopportune times, not when you guys are la-te-da riding on perfectly smooth bike paths with no one around.

Every ebike sold in the world comes with this standard safety feature. Arguing against the need for ebrake cutoff baffles me.

Alan B said:

Even with a standard ebike that is within US Federal regulations, the ebrake (brake cutoff) serves several important safety purposes, and is required by that Federal regulation that defines an electric bicycle with regard to commerce.

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Not to digress further off topic, but unless there have been regulation changes, I believe this is incorrect.

Since 2002, ebikes have been regulated at the Federal level by the Consumer Product Safety Commission according to HR727 which was approved to clarify the CPSC's jurisdiction over ebikes. Ebrakes are not discussed.

That said, the regulatory landscape does change, and it can be difficult to stay abreast of these things...

It would be good if you would please cite the Federal regulation requiring ebrakes or any other new changes over HR727 so these developments can be better understood separate from the context of this particular thread. Thanks.

I have not looked at regulations recently, but as I recall brake power cutoffs were a requirement in the federal rules. Someone should verify that. Those rules are written for consumer safety, and protection of consumers unfamiliar with the technology. Many systems are PAS but even throttle systems with unfamiliar users have need of this safety feature. At any rate, I didn't check and don't have time at the moment to do so. Apologies if my memory is incorrect.

Alan B said:

I have not looked at regulations recently, but as I recall brake power cutoffs were a requirement in the federal rules.
Someone should verify that.

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https://www.congress.gov/107/plaws/publ319/PLAW-107publ319.pdf

John in CR said:

Chalo said:

My point was only that at bicycle power levels, a fail-on throttle condition can easily be stopped with one normal brake and the battery disconnected with the free hand.

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Power is torque times rpm, so it's perfectly reasonable to build a climb anything very slow ebike that's 100% legal in any jurisdiction. In fact, it wouldn't have to be slow. eg If I was forced to live under the 750W power limit rule, then I would want to build a bike that had 750W of output at the wheel from 1rpm up the 30mph or so that I could get out of it,

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1HP at 1rpm doesn't sound like bicycle power levels to me. In fact, it sounds like it would surely break bicycle parts. A good bicycle brake will stop a bicycle, as I said.

(I think the technical approach you've outlined is a great way to work within regulated e-bike definitions, and I've said so elsewhere. I think manufacturers should do it. But such a bike isn't by the nature of its construction a bicycle.)

Failures tend to occur at the most inopportune times, not when you guys are la-te-da riding on perfectly smooth bike paths with no one around.

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Not sure who "you guys" are, but my bike is how I get around and the streets here look like people have been digging them up for fool's gold. The best way to avoid breaking a bicycle is to operate it within proven parameters of speed and power, and not demand of it things that it was not designed to do.

My BBS02 came with switched levers. I don't use them, for safety reasons. Why? Because I use locking levers instead. My bike is more likely to hurt somebody by falling over (likely and potentially dangerous) than it is from an uncontrolled power runaway (unlikely and not very dangerous), and locking levers help keep it from falling over.

Heck, I think all e-bikes should have locking brake levers, and I'm baffled that anybody would think otherwise.

The brief 2002 federal note that Teklektic linked doesn't mention brake cutouts (is that all there is on the federal level?), but many statutes do call for it. I recall a longer document, not sure which it was. It may have been the older California rules which allowed 1kw that were in effect when I got into ebiking. I didn't find the older California rules, but I did find a number of the state and provincial rules for the US and Canada that do call for motor cutout while brakes are engaged. Regardless of the source, it is a common rule. Manufacturers wanting to sell ebikes in various locations will include them in their products unless they make different variants for each target market. I don't recall seeing major commercial ebikes lacking brake cutouts.

From a safety standpoint there are many reasons to have a motor cutout. We've already beat that one enough.

I just checked to be certain, and my hydraulic, locking front brakes on the Borg do have an ebrake cutout switch, so they are absolutely available. I agree with Chalo, locking brakes are very useful to help a parked bike not fall down, or a trike not roll away. But locking brakes can have cutout switches on them, so it is not a reason for skipping the disconnect. There are also other ways to develop the cutout switching.