eABS three wire connection

[ptr66]

I have recently brought a Wuxi SL-QX041KZ controller, which came with an S866 display panel. Going through the connections, the facility for eABS caught my eye, and I started to do some research into it. Obviously, it's not the same as 'real' ABS found on a car, but looks like it provides some measure of electrically assisted braking by dumping the waste energy as heat in the controller and motor windings. Whilst I appreciate this could potentially be a problem if there was excessive heat build up, I'm interested to find out if it actually works.
The question is how is it connected? My unit has three coloured wires going to a plug. The included diagram lists these as being red +5V positive, black ground (so far, fair enough) and a brown wire labelled 'Electronic brake signal'. So what are you supposed to make of that?
Does it go to an eBrake switch, taking it high or low depending on if the brake lever is pulled? Should it go to some linear hall effect sensor built into the brake lever to provide proportional e-braking, according to the force of the pull? Or perhaps it should go to a thumb throttle, that again could provide a level of proportional braking depending on its position?
There seems to be no solid information on this area, so any help or feedback from personal experience would be much appreciated......

​

 

[amberwolf]

Most people just call it "regen braking".

Terminology used by sellers varies depending on what words they copied from someone else, how well or poorly that was originally translated into whatever language is used in the ad, what they actually understand / know about what they sell (almost nothing, most of the time), and whether they lie about stuff to sell more things (whcih happens a lot, so sometimes the lie isn't by the seller you buy from but the one that they copied their ad from).

Most controllers, especially cheaper ones, only have on/off regen, which activates at the full amount of whatever level it is designed and/or factory-setup with.

This is usually just controled bya switch in the brake lever (or activated by activating the mechanical brakes in some way).


Almost no controllers support variable regen. Most of the ones that do are FOC types (VESC, Phaserunner, Lebowski, maybe Lishui, etc). Some Sabvotons, Votols, Fardriver, others I don't recall the names of. Some non-FOC types do, like the old Grinfineons (no longer available). Don't recall if any Kellys do.

This can be activated in a number of ways. Some use a switch to turn the mode on (same as above), and a separate analog control of whatever type, which may be dedicated to braking, or it may just be the throttle itself--while brake is engaged, it's a brake control, while not, it'a throttle. Some use just the analog input. Some use the throttle input only, and when the voltage is above some limit it's a throttle, and below that it's a brake. Etc.


The way either type works depends on the specific controller design, and can be different for different controller firmware versions. Some brake ahrder as you get slower, some brake less as you get slower, some only start braking *below* a certain speed, and/or *above* some other speed. There's no single way it's implemented, and documentation on behavioral specifics is nonexistent even in the best-documented ones, so you'll only find out how yours works once you have a controller wired up, programmed, and go ride to test it.


Most of the FOC types are programmable so can be setup by the user for some of the braking options as well.

Most of the non-foc types even when programmable don't have braking options--they just do what they do.


Most regen braking is done by creating a voltage higher than the battery presently is at, so it forces current back intot he batter, laoding down the system and creating drag ont he motor. This makes some heat but some energy recharges the battery. There are situations wehre this is a problem (a thread from earlier this week that I posted in has details on that).

Some use plug braking, basically shorting the motor windings with the controller FETs. This turns all the braking into heat inside the motor, controller, and wires between them.



There are advantages and disadvantages to each version of each of these things, so which one is better suited to you depends on your specific system and how you wish to use it, and whether you want to learn new control methods with your hands/etc to do braking, or you want to keep the safest possible control method which is whatever you already learned (normally that's using a brake lever for a brake, and not any other type of control).

 

[amberwolf]

The question is how is it connected? My unit has three coloured wires going to a plug. The included diagram lists these as being red +5V positive, black ground (so far, fair enough) and a brown wire labelled 'Electronic brake signal'. So what are you supposed to make of that?

You'd need to know whether the controller has variable braking or on/off braking, for what signal it expects.

On/off most of the time expects you to ground the signal line to activate.

Variable most of the time expects the same votlage range as a hall throttle--whatever range the controller you have in hand expects, since that's a different range for each controller. This usually requires three wires, 5v, ground, and signal, but there are some that use a pot rather than hall control, so those can use just two wires, signal and ground.

Some controllers (like the ancient Lishui the Fusin kits came with) came with brake levers that used hall sensor switches (just like in a motor) so they used three wire cables, for 5v, ground, and signal. But they would also work with regular switches, and two wire cables, just signal and ground. Neither one did variable braking, just on/off.

 

[amberwolf]

Personally, on my SB Cruiser 2WD cargo trike, I use the Phaserunners right now, which offer programmable variable braking.

The versions I have use just the throttle input to choose whether braking or accelerating, and by how much. the actual switchpoint is programmable. I think mine is setup for 0.8v and below to brake, and above that it's acceleration.

The force is also programmable. But the curve it uses, and how it behaves, is not programmable and not described anywhere.

Because I actually use the pedals to control acceleration, and the left brake lever to control both rear motors' braking force (right lever controls front mechanical brake), I use the Cycle Analyst v3 to translate the pedals into a throttle signal, and to "mix" the brake lever and throttle into a single signal for both controllers.

The CA is also only designed with a single throttle input...so I use a relay setup to switch between an actual throttle used as a throttle (which I don't use much but sometimes require for startups from a stop). and a cable-operated throttle pulled by a typical ebrake lever that has a switch built in. So the switch in the lever engages the relay that disconnects the throttle from the CA's throttle input, and then connects the braking COT to it instead (antoher relay engages a brake light), *and* uses the CA's ebrake input to tell the CA that the voltage it's getting on the throttle input is now for braking, so the CA sends a *decreasing* voltage below 0.8v on it's throttle output now, until the brake lever is released.

If that sounds complicated, it is, but it was the only way I could make my system do what I needed, when it was built. :/

There are some potentially simpler ways I could do it now, but what I have works reliably and well, so I leave it alone.

 

[ptr66]

I have recently brought a Wuxi SL-QX041KZ controller, which came with an S866 display panel. Going through the connections, the facility for eABS caught my eye, and I started to do some research into it. Obviously, it's not the same as 'real' ABS found on a car, but looks like it provides some measure of electrically assisted braking by dumping the waste energy as heat in the controller and motor windings. Whilst I appreciate this could potentially be a problem if there was excessive heat build up, I'm interested to find out if it actually works.
The question is how is it connected? My unit has three coloured wires going to a plug. The included diagram lists these as being red +5V positive, black ground (so far, fair enough) and a brown wire labelled 'Electronic brake signal'. So what are you supposed to make of that?
Does it go to an eBrake switch, taking it high or low depending on if the brake lever is pulled? Should it go to some linear hall effect sensor built into the brake lever to provide proportional e-braking, according to the force of the pull? Or perhaps it should go to a thumb throttle, that again could provide a level of proportional braking depending on its position?
There seems to be no solid information on this area, so any help or feedback from personal experience would be much appreciated......

​

I should have said in the original post, the controller does have the usual pair (F&R) of 2 wire brake connectors, that switch off motor drive as soon as the brake lever switches operate. This looks like the eABS is an additional feature, so as one contributor suggested, maybe a relay will be needed so that the brake switches are disabled when eABS is in operation (if I read it right?). Anyway, thankyou to all those who have contributed so far, as they are very helpful in this respect....