# Independent Regenerative Control



## meanderingthemaze (Jan 25, 2010)

Does anyone know what is required to implement a separate lever that would, independent of throttle and brake, control the regen amount?

Would it require a special connection point on the controller? Would the manufacturer have to be convinced that it was worthwhile to add that feature?

Or are people already doing it?

Thanks


----------



## Amberwolf (May 29, 2009)

I'm sure you could add such a control, but I am not sure I see the point of it, since you will be braking by doing regen by definition. 
________
Herbalaire Vaporizer Temperature


----------



## meanderingthemaze (Jan 25, 2010)

Hey Amberwolf,

Do you know how? I'm guessing it would be different depending on the controller. 

With the motor/controller I'm planning to use (Curtis)m the amount of regen can only be adjusted through the use of software (with a computer), but as I understand not on the fly. 

The reason one would like this feature would be to control on the fly the amount of regen you need in any given driving circumstance which is too lengthy to list here. Rainy conditions versus snowy versus dry. Street versus freeway just to name a few. Also it would be a lot closer to the way a "normal" brake works, ie: the amount of brake you need can be adjusted by the difference in the pedal lever.


----------



## Amberwolf (May 29, 2009)

meanderingthemaze said:


> The reason one would like this feature would be to control on the fly the amount of regen you need in any given driving circumstance which is too lengthy to list here. Rainy conditions versus snowy versus dry. Street versus freeway just to name a few. Also it would be a lot closer to the way a "normal" brake works, ie: the amount of brake you need can be adjusted by the difference in the pedal lever.


Ah; I misunderstood what you were asking for--I thought you were looking for a separate control to *engage* regen in different amounts, not to change the amount you get out of it when you do use it. 

In that case what I would recommend is using a PWM circuit controlled by the brake lever/pedal so that the harder you press the pedal the higher the dutycycle is. That PWM signal would be fed to the brake input of the controller. Then the brake would be pulsed and only regen as much as you like. The controller would be set for a max regen of whatever max you normally want to have, and left that way.

The device would basically be like a very small motor controller but with no power-output stage. You could in fact use a small 12V scooter controller for this, and simply remove it's power output stage, tapping directly onto the gate output signal from it's control chip to provide the braking output PWM. The brake pedal's pot or hall would go to the throttle input of the scooter controller. Any of the zillion other types of DIY PWM controllers would also work, just leaving off any power stage, and using something to buffer the PWM output signal to ensure it is within the voltage range of the brake input on your motor controller. 

This would probably be safer than trying to control a separate regen amount control while in the process of braking, especially if you needed to brake hard and fast but you had last set the regen amount to something really small, and were depending on the regen to help you stop. 

It would not affect your mechanical brakes, which would still engage the same way they used to.

Just setup the hall or pot you use to control the amount of regen so that it engages regen before engaging the mechanical brakes, so most of your deceleration is always going into regen rather than wasted as heat in the discs/drums, but when you slam the brakes on you'll still get full regen as well as full mechanical braking. 

How well this would work depends on how well your controller can handle pulsing the brake line. If it has any kind of integration/ramping on it's brake input, this will probably not work, or at least not well. 


The only other ways I can think of require modifying the controller electronics and/or firmware. 

Well, if the controller does not have to be rebooted after programming, or be in a special mode to be programmed (meaning it can be done while driving) then you could get ambitious and build an MCU setup that takes a brake controller (hall or pot) input and translates that into a value to be programmed to the controller, then continuously programs the controller with the new input. Or use a control on the dash instead of on the brake, if you only wish to change it occasionally. But I doubt the controllers can be programmed during use--it seems a dangerous thing to allow in at least some cases. 
________
Live Sex Webshows


----------



## meanderingthemaze (Jan 25, 2010)

Cool, that's interesting. My only concern in that setup is that there would not be enough play in the brake pedal before they actually engaged to have much control. Which is why I thought to put a separate lever.

And if I follow you, why couldn't you connect the PWM to a separate lever if it's just working off a pot?

I have also considered installing a "car-puter" such that I can tap into the controller at any time I'm in the car, but you may be right that messing with it while driving could be dangerous.

Finally, I have always been curious about the normal setup of regen, ie: being attached to the throttle. It somehow seems ineffient to me because when you release the throttle you may not always want to have it engage. But I guess you could always disengage the motor with the clutch. I guess once I'm driving it it will become more evident what I should do.

Thanks!


----------



## Guest (Apr 10, 2010)

The controller can control the amount just fine with the pot connected to the pedal. I assume you are going to be either doing AC or SepEX DC. Series DC won't work at speeds that the car can go. SepEx can and so can AC.


----------



## Amberwolf (May 29, 2009)

meanderingthemaze said:


> Cool, that's interesting. My only concern in that setup is that there would not be enough play in the brake pedal before they actually engaged to have much control. Which is why I thought to put a separate lever.


That entirely depends on your existing brakes, and whether or not you can adjust them for more play. 



> And if I follow you, why couldn't you connect the PWM to a separate lever if it's just working off a pot?


You *could*, it's just that in my view, it's not as safe. What happens if you are trying to stop and something blows up preventing regen from working at all, and it takes you an extra split second to realize it's not working and then start pressing the regular brake? 

If you use a dash- or steering wheel-mounted regen engage control, then at least your foot is easily able to find the mechanical brake pedal while your hands are otherwise occupied, in such a situation. If you use a separate pedal then you also have to move your foot to the mech brake conciously, another delay. 

But also if you are using a dash/wheel-mounted control, it's one more thing to remember to use to stop, instead of the regular pedal, so you have to retrain yourself. 

I'm currently working on getting regen working on my ebike, and will be using an experimental version of this type of thing there, using a linear hall sensor to replace the switching one in the "ebrake" handle I have for it, or a linear sensor attached to my regular braking system/handle. 




> I have also considered installing a "car-puter" such that I can tap into the controller at any time I'm in the car, but you may be right that messing with it while driving could be dangerous.


And likely not even possible.  I'd bet that most of them must be either disconnected from the programmer cable to run, or must be rebooted after programming in order to accept the changes, or other similar designs preventing programming while driving. The Soliton1 might be different, based on what little I read of it's web interface stuff here on the forum, some time ago. So you'd need to park first, in most cases, most likely. 




> Finally, I have always been curious about the normal setup of regen, ie: being attached to the throttle. It somehow seems ineffient to me because when you release the throttle you may not always want to have it engage. But I guess you could always disengage the motor with the clutch. I guess once I'm driving it it will become more evident what I should do.


It depends also on how your controller works. If it works as a "demand-speed" controller, like my 2QD and some other golf-cart controllers, it is tied into the throttle because it is trying to keep you at the speed you set. So if you lower throttle input, it assumes you meant to slow down, and it's design causes it to start regen braking to get you down to the new speed.

If the controller simply provides acceleration all the time the throttle is active, up to the point where current flow into the motor meets the throttle's setpoint, and then simply does not do anything once the throttle is let off, then it would do what you want it to do. That's how most ebike controllers seem to work (since it's normal to want to coast for long periods once at speed, without using power to maintain that). Then regen is activated once the brake input goes active. But most ebike controllers only have an on/off type brake input, so they have no idea how MUCH regen you want, and just go whole-hog trying to stop you.  I don't know if that's also true of larger types of EV controllers. 


Oh, one other issue you could have with regen in a car is that most of the conversions and such I have read about use advanced timing on the motor to optimize for higher voltage input. That means that if you try to use regen braking on such a motor, it could destroy itself. You'd need to leave it at neutral timing to deal with that. That's as much as I know on the motor end of things, though, so you'd have to search the forums for the rest of it. 
________
MANUELATIN live


----------



## GerhardRP (Nov 17, 2009)

Amberwolf said:


> You *could*, it's just that in my view, it's not as safe. What happens if you are trying to stop and something blows up preventing regen from working at all, and it takes you an extra .split second to realize it's not working and then start pressing the regular brake?


I strongly endorse this remark.. It is doubly important when you loan the car to someone.. operation should be as close to ICE behavior as possible.
I would control regen with a pressure sensitive resistor attop the brake pedal which would behave like a well adjusted "normal" system
Gerhard


----------



## Olaf-Lampe (Feb 24, 2010)

Why use a PWM circuit to adjust regen when you already have a analog potmeter on the brake?
Just add another potmeter in line to the brake-potmeter and reduce the regen current to anything you like.
If your system only has a brake switch to enable regen ( without motorbrake input from the acc-pedal ) you can not do much.
I highly doubt that a PWM controller of a scooter could be useful ( eg. gate voltage must fit controller input voltage, switching frequency has to be just right ). Especially when the controller has a ramp function behind the brake switch input, which is most common.

Give us the modelnumber of the curtis controller and we'll see what can be done. There is no common solution for every drive system.

-Olaf


----------



## JRP3 (Mar 7, 2008)

meanderingthemaze said:


> Finally, I have always been curious about the normal setup of regen, ie: being attached to the throttle. It somehow seems ineffient to me because when you release the throttle you may not always want to have it engage.


I think you'll find a pedal position that allows coasting without regen, just don't lift off the pedal all the way. Regen dependent on throttle position makes good sense, it's the way engine braking has always worked on ICE's with manual transmissions. You could actively modulate regen intensity by throttle position with the right foot while braking with the left if you were actually in a situation where you wanted to stop with less regen for some reason, ice or snow or something.


----------



## Duncan (Dec 8, 2008)

Hi Meandering

Try this link

http://www.metricmind.com/audi/main.htm

I don't think it is finished yet but his modified shift lever may be what you need


----------



## meanderingthemaze (Jan 25, 2010)

Hey Guys, 

Read all the replies and understand the concern. I am familiar with the concept of attaching to the braking pedal and the throttle pedal. 

In fact, I got a chance to drive the Mini-E over the weekend and that is configured to the throttle, but in a more complicated way than I understand most conversions are setup. With the Mini-E, when you take your foot off the throttle, there is a delay of about 3/4 seconds before the regen kicks in. And then when it does, it isn't a constant amount of regen, but rather is a function of the pedal position. So in the throttle up position you get full regen, but if only release the pedal half way, then it gives regen but less powerful. 

It seems like it is setup to kick in regen when your pedal is on the up motion, and if the pedal is on the down motion it thinks you want to accelerate and doesn't engage regen. There is definitely some calculating by the car trying to figure out if you want to slow down or maintain your current speed.

It is strange at first, but something you can definitely get used to. And I didn't need to use the brakes once, although I wasn't in traffic. 

That said, I thought it would be interesting to have a regen control on the shifter like this:









As to what controller I'm using, it's a Curtis, but I don't which one, guessing the AC 1238. I'm waiting to hear back from the seller. Maybe some of you are already familiar with the motor/controller from High Performance EVs, here's a link to the motor I'm using...
http://hpevs.com/drive-systems/ac-50

My question really has to do with whether or not I would have to do any modifications to the controller or if it's already setup to attach the regen control to anything I want. From what I understand, the variables for regen have to be modified via software. If I can achieve this via a PWM, or something similar, it would be good to know if it's possible.

Thanks


----------



## JRP3 (Mar 7, 2008)

You have to buy either their hand held programmer or their programming software to adjust anything on those Curtis controllers, around $500 I think  They are not setup for adjustable regen from the factory.

You can find the manual for the Curtis 1238-75 that comes with the AC50
here http://www.curtisinstruments.com/index.cfm?fuseaction=cdatasheets.dspListDS&CatID=1&siteID=1


----------

