E braking. How do i use it?

Get all your technical information about electric bikes here.
Post Reply
levleon13
1 W
1 W
Posts: 62
Joined: Dec 25, 2016 4:29 pm

E braking. How do i use it?

Post by levleon13 » May 19, 2017 6:29 am

Hey guys, sorry for the noob question, but i have this controller (1500) that has low/high level braking plugs, each are 2 wires. Now shorting them doesn't do the job. How do i wire them? My brake pads wearing out every month on saints, and theyre not that cheap.

User avatar
dogman dan
100 GW
100 GW
Posts: 34330
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: E braking. How do i use it?

Post by dogman dan » May 19, 2017 6:47 am

If your controller does not have another set of wires that you connect to enable regen, then you are SOL. There might be possibility of opening the controller, and installing those wires, but I dont' know how to do that myself.

levleon13
1 W
1 W
Posts: 62
Joined: Dec 25, 2016 4:29 pm

Re: E braking. How do i use it?

Post by levleon13 » May 19, 2017 9:17 am

Forgot to mention that i dont seek for regeneration. Only motor stopping itself.

gderou
10 µW
10 µW
Posts: 5
Joined: May 12, 2017 6:55 am

Re: E braking. How do i use it?

Post by gderou » May 19, 2017 10:29 am

I had a similar question (https://endless-sphere.com/forums/viewt ... 30&t=88252).
My controller didn't have any dedicated wire, so I had to solder a wire in it (that activates e-brake as soon as I press the brake lever).
In your case, I suppose that the wires are to be connected to something (ground ?) to activate 2 modes of e-brake (low and high ?).
Do you have a picture of the controller ? I know there are LCD controls that give the option of choosing between several modes of e-brake, but I don't know how they are connected…

From what I understand e-brake and regen are the same thing - if you activate one you activate both and it means that current with flow from the motor to the battery (where would it go otherwise ?). I don't know what the impact can be though (controller heat / battery heat ? So far so good for me so I hope it continues this way…) and whether there are things to be careful about before activating.

NB: I am driving an electric scooter and not an e-bike, but that should be the same thing.
NB2: this is what I have gathered - I am no specialist, so it is completely possible that I am totally wrong on the subject - any correction / links to educate myself would be appreciated ;-)

User avatar
Chalo
100 GW
100 GW
Posts: 6169
Joined: Apr 29, 2009 11:29 pm
Location: Austin, Texas

Re: E braking. How do i use it?

Post by Chalo » May 19, 2017 12:03 pm

gderou wrote:From what I understand e-brake and regen are the same thing - if you activate one you activate both and it means that current with flow from the motor to the battery (where would it go otherwise ?)
You know how your motor seems to lock up if you touch the phase wires together? That's the simplest kind of e-braking, which is also called "plug braking". The energy gets dissipated into the motor windings mostly. Other e-braking systems use a power resistor as the load. Diesel electric locomotives do that. Some other systems actively use battery power to resist the motor's rotation.

My first e-bike had a Curtis DC motor controller in which the short-circuit type of e-braking was an automatic feature. Either the motor was driving forward or it was being electrically braked. It would have driven me nuts except that I put a freewheel on the motor drive.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

gderou
10 µW
10 µW
Posts: 5
Joined: May 12, 2017 6:55 am

Re: E braking. How do i use it?

Post by gderou » May 19, 2017 12:22 pm

Yes, reading another post about regen, I realised that it was possible to have brake only (no regen) - so I guess that is highly dependent on the controller.
I must admit that I have never played with my motor phases - so I can only imagine what you are talking about…

So now I don't if I have regen, but I definitely have e-brake enabled on my scooter. Where does all that energy go is beyond my current understanding - but I may know when a part breaks :p

User avatar
Icewrench
10 kW
10 kW
Posts: 871
Joined: Sep 07, 2008 4:54 pm
Location: Seattle Wa USA

Re: E braking. How do i use it?

Post by Icewrench » May 19, 2017 3:17 pm

E brake hi might be looking for a positive voltage like to a brake light.

Brake low might be looking for a ground signal to activate motor cut off.

John in CR
100 GW
100 GW
Posts: 13764
Joined: May 20, 2008 12:58 am
Location: Paradise

Re: E braking. How do i use it?

Post by John in CR » May 19, 2017 10:52 pm

When shorting the 2 ebrake low wires together did u have the motor at significant rpm? If so and you also tried the ebrake hi by supplying anything from about +10V up to +pack voltage (and a common ground to battery negative), then you don't have electric braking and the 2 are really just an "ebrake cutoff" which cuts motor power when braking (a basic safety feature even if you don't have regen enabled.

There are some few controllers that have electric braking that isn't regen. I only have experience with one from Greentime, and it was quite nice in that the braking force worked nice and smooth all the way down to a stop, unlike most cheap controllers' regen. Because it dissipated the energy of braking in the controller, wiring, and motor windings, you do have to be careful of heat buildup and related failures. In that regard it's best to just get a controller with regen. You get some energy back into the battery, but the biggest plus for me is the greatly reduced brake maintenance.

levleon13
1 W
1 W
Posts: 62
Joined: Dec 25, 2016 4:29 pm

Re: E braking. How do i use it?

Post by levleon13 » May 24, 2017 8:47 am

I guess my conclusions here is to get a controller that supports the feature huh.. Hoped for some diy shortcut.

User avatar
Alan B
100 GW
100 GW
Posts: 7027
Joined: Sep 11, 2010 7:43 am
Location: San Francisco Bay Area, USA
Contact:

Re: E braking. How do i use it?

Post by Alan B » May 24, 2017 9:07 am

The ebrake feature on my Borg's Sabvoton controller requires a switch closure to activate it, and a variable voltage to determine how strong the braking is. It smoothly combines regen at higher speeds with reverse power at low speeds to provide variable braking that can be very strong down to very low speed like one mph. By adjusting the controller's programming the braking can be adjusted, it can be set to skid the tire if desired. It is an excellent feature, and on that bike I use it to replace mechanical braking in the rear wheel (and actuate it from a normal looking brake handle that puts out the required signals), the front wheel has dual discs so there's plenty of mechanical backup. The brake pads last a long time, never have worn any out.

levleon13
1 W
1 W
Posts: 62
Joined: Dec 25, 2016 4:29 pm

Re: E braking. How do i use it?

Post by levleon13 » May 25, 2017 12:48 pm

Alan B wrote:The ebrake feature on my Borg's Sabvoton controller requires a switch closure to activate it, and a variable voltage to determine how strong the braking is. It smoothly combines regen at higher speeds with reverse power at low speeds to provide variable braking that can be very strong down to very low speed like one mph. By adjusting the controller's programming the braking can be adjusted, it can be set to skid the tire if desired. It is an excellent feature, and on that bike I use it to replace mechanical braking in the rear wheel (and actuate it from a normal looking brake handle that puts out the required signals), the front wheel has dual discs so there's plenty of mechanical backup. The brake pads last a long time, never have worn any out.

this is an extra option in the config right ? i can also trigger it with just switch closure right( no sensetivety) ?

do you have your thread for dual disks ?
i would really like to see and learn the details about the conversion .

User avatar
Alan B
100 GW
100 GW
Posts: 7027
Joined: Sep 11, 2010 7:43 am
Location: San Francisco Bay Area, USA
Contact:

Re: E braking. How do i use it?

Post by Alan B » May 28, 2017 12:58 am

Both the dual discs and the Sabvoton controller setup are covered in the GreyBorg thread.

On the dual discs, a front fork with dual disc brake mounts is required, plus a hub that has dual disc mounts. Then you add a dual caliper single lever hydraulic brake setup (designed for a tadpole trike).

The particular controller firmware in my Sabvoton has the variable ebrake feature. They were ordered this way from the factory, I've heard that not all units have the feature, or that it isn't implemented the same way. My unit does suffer from a scaling error so the calibration settings have to be experimented with, but it produces wheel skidding braking if desired.

I started with a standard ebrake lever which contains a switch and a normal mechanical cable pulling mechanism. I converted the cable pulling portion to a linear voltage generating lever using a magnet and a linear hall sensor. So the net result is a naturally operating brake lever. The more you pull it, the more braking you get. When the speed drops to about one mile per hour the ebrake drops out. It will re-engage if the speed rises again, however I use a foot or the front friction brake to do the rest of the deceration and holding. In actual use the rear ebrake is used for the majority of braking, then the friction front brake is used for the remainder. The brake pads last basically forever, but I do find that I need to brake hard with them occasionally to break the glaze from continual minor braking.

Certainly one could change Sabvoton controller configurations, and perhaps apply a fixed voltage to the "braking level" input and create a more primitive setup similar to standard controllers, but why would one want to do that?

999zip999
100 GW
100 GW
Posts: 8144
Joined: Jan 10, 2010 1:40 pm
Location: Dana Point So. Cal

Re: E braking. How do i use it?

Post by 999zip999 » May 30, 2017 3:08 pm

You should also have a handlebar kill switch I have mine on the left side just a thumb take down.

User avatar
Alan B
100 GW
100 GW
Posts: 7027
Joined: Sep 11, 2010 7:43 am
Location: San Francisco Bay Area, USA
Contact:

Re: E braking. How do i use it?

Post by Alan B » May 31, 2017 12:58 am

999zip999 wrote:You should also have a handlebar kill switch I have mine on the left side just a thumb take down.
+1, on/off or kill sw is an excellent feature.

levleon13
1 W
1 W
Posts: 62
Joined: Dec 25, 2016 4:29 pm

Re: E braking. How do i use it?

Post by levleon13 » Sep 05, 2017 4:00 am

Chalo wrote:
gderou wrote:From what I understand e-brake and regen are the same thing - if you activate one you activate both and it means that current with flow from the motor to the battery (where would it go otherwise ?)

You know how your motor seems to lock up if you touch the phase wires together? That's the simplest kind of e-braking, which is also called "plug braking"
. The energy gets dissipated into the motor windings mostly. Other e-braking systems use a power resistor as the load. Diesel electric locomotives do that. Some other systems actively use battery power to resist the motor's rotation.

My first e-bike had a Curtis DC motor controller in which the short-circuit type of e-braking was an automatic feature. Either the motor was driving forward or it was being electrically braked. It would have driven me nuts except that I put a freewheel on the motor drive.

is there any way to modify a controller to achieve this ?

Cieszyn
1 µW
1 µW
Posts: 3
Joined: Oct 21, 2012 4:22 pm

Re: E braking. How do i use it?

Post by Cieszyn » Oct 27, 2017 5:20 am

Hi,
I have a setup with two wheels, one is powered by a controller, with the other I have used a switch to short circuit the motor (plug brake). I would like to do the same with just one motor (see my crude idea in the attachment).
How to do it? Or could you direct me to the appropriate thread?
thanks
TC
Attachments
Notatka5_0.jpg
(239.6 KiB) Downloaded 6 times

User avatar
amberwolf
100 GW
100 GW
Posts: 23963
Joined: Aug 17, 2009 6:43 am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: E braking. How do i use it?

Post by amberwolf » Oct 27, 2017 1:58 pm

You can do it like that but if anything happens that accidentally causes the switch to short the controller's wires, then the controller will blow up.

Cieszyn
1 µW
1 µW
Posts: 3
Joined: Oct 21, 2012 4:22 pm

Re: E braking. How do i use it?

Post by Cieszyn » Oct 29, 2017 10:46 am

Please advise on a better aproach. Additionally I wanted to use mosfet so there would be no sparks on switching on and off, plus they would handle the wattage better, but the mosfet is a one way switch isn't it?

User avatar
Alan B
100 GW
100 GW
Posts: 7027
Joined: Sep 11, 2010 7:43 am
Location: San Francisco Bay Area, USA
Contact:

Re: E braking. How do i use it?

Post by Alan B » Oct 29, 2017 11:09 am

MOSFets are two way (like low value controlled resistor when on), however they have an inherent diode across them. So to make a bidirectional switch two FETs are used in series with the diodes opposing to avoid that current path when the FETs are open.

User avatar
amberwolf
100 GW
100 GW
Posts: 23963
Joined: Aug 17, 2009 6:43 am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: E braking. How do i use it?

Post by amberwolf » Oct 29, 2017 5:05 pm

You can look up some of the threads about Ideal Diodes made from FETs to get an idea of what to do to build such a switch. Methods also has a thread somewhere about something like that, and Fechter may also have one. AFAICR they are all about making a battery switch, but the same thing applies for what you want.


However, you still have the same problem--anything that fails in a way that shorts the phase wires while the controller is connected and powered on can blow up the controller.



Also, if the plug braking is sudden and strong enough it can lock up the wheel and cause loss of control. Shorting only two phases gives less braking than all three.

User avatar
Alan B
100 GW
100 GW
Posts: 7027
Joined: Sep 11, 2010 7:43 am
Location: San Francisco Bay Area, USA
Contact:

Re: E braking. How do i use it?

Post by Alan B » Oct 29, 2017 7:59 pm

One way to make Regen is to pulse a short across the motor leads for a brief time (PWM), this generates current in the motor and deceleration. Then the short is released (at some rate like 10 khz) and the energy in the motor's inductance generates a voltage pulse which rises until it finds a path to follow. The FETs in the controller have inherent body diodes in them that form a three phase rectifier back to the battery, so the regen energy goes back into the battery (providing the BMS provides a path for it) (perhaps via the inherent body diodes in it's own FETs).

Motor controllers generally have an option to do this themselves, but an external set of FETs should do as well. In building such a circuit one would want to disable the controller either via pulling the throttle to zero electronically or generating an ebrake signal to the controller so it does not attempt to provide power to the motor while it is braking in this way. Sequencing the signals with appropriate time delays should protect the controller against driving power into the shorting FETs.

Cieszyn
1 µW
1 µW
Posts: 3
Joined: Oct 21, 2012 4:22 pm

Re: E braking. How do i use it?

Post by Cieszyn » Oct 31, 2017 6:53 am

Alan B wrote: In building such a circuit one would want to disable the controller either via pulling the throttle to zero electronically or generating an ebrake signal to the controller so it does not attempt to provide power to the motor while it is braking in this way. Sequencing the signals with appropriate time delays should protect the controller against driving power into the shorting FETs.
If I understand correctly, I could use standard brake low signal to dis able acceleration, and without disconnecting the controller, as long as it is not giving power to the motor, I could short the motor phases? Without damage?
What does the brake low/ brake high do? Does it cut out the throttle or mosfets?

User avatar
amberwolf
100 GW
100 GW
Posts: 23963
Joined: Aug 17, 2009 6:43 am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: E braking. How do i use it?

Post by amberwolf » Oct 31, 2017 2:40 pm

Cieszyn wrote:What does the brake low/ brake high do? Does it cut out the throttle or mosfets?
Depends on the controller. some of them just turn off the FET outputs. Some of them engage a form of braking that modulates the FETs. Some of them engage a form of braking that actively outputs power from the FETs to force the motor to slow down faster.

You'd have to check your controller specs or test it to see which it does.

Post Reply