# GE EV100 regen braking



## Qer (May 7, 2008)

crazybry79 said:


> I can't remember where, but I thought that someone was saying that you can not use the regen feature on the DC conversions.


People say a lot so the odds that everything people say is the truth is, err... let's just say that it's not 100% accurate. 

Every motor can also work as a generator and there's definitely DC-motors that can be, and are, used for regen. One of the easiest motor types there are for doing regen is the SepEx, you can get it to reverse and regen rather easily by changing the direction of the field and since the field has a relatively low current this is a rather cheap feature to add to the controller. This is used in for example the old Renault Clio Electric which has a SepEx in direct drive.

The myth that DC can't regen seems to come from the fact that most DIY:ers use series wound motors that are advanced to survive a higher top voltage than they're made for. This is done by advancing the brushes but that also means that the voltage tolerance drops if you reverse the motor and that if you try to regen the motor you'll probably blow it up or at least wear down the brushes very rapidly.

With a neutrally timed motor a series wound motor can regen, but the question is if it's worth it. The regulation is a bit instable since the motor creates it's own magnetic field and thus the more the current goes up, the bigger the field gets which increases the current and enhance the field... Rinse, Repeat, Ragnarok. Therefore regen with a series wound motor means constant controller surveillance and compensation to avoid that the current goes out of hands. To make things worse you have to shift the field for it to work which means pretty expensive contactors since the field in a series wound motor is the full motor current.

So even if a series wound motor CAN regen, it doesn't quite seem worth the trouble and generally speaking regen seldom makes such an impact as many seem to think. To begin with you have all the losses in transmission, motor, controller and battery times two before you've converted movement to electricity and then back to movement again (which will leave you with a total efficiency of a whooping 25% or so) and then there's the question about the terrain too. If you live in a hilly area or do a lot of stop and go regen can contribute to the range, but if you mainly cruise it won't do a thing for you.

AC-motors and other brushless motor designs can always regen since the hardware is built in a way that allows regen for free (well, more or less at least). And that's probably why the myth still roams free that AC can but DC can't regen. All motors can regen, but depending on the type of motor it might not be worth it. For brushless motors it's pretty simple, it doesn't cost anything (a wee bit more software, but not too complicated), for SepEx it cost a bit more in hardware but not much, but for series wound motors it seems to be more of a problem than it's worth.

However, it's still a myth.


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## crazybry79 (Jun 15, 2010)

OK, I'm following you.....sort of...

Bear with me, as I am an electrical novice, 

Now, I understand (well, don't _understand_, but I belive you  ) about the current building, and enhancing the field, ect. With that in mind, I grasp the concept of the complexity of the controller.

What I'm not understanding (again, bear with me.....electrically simple minded) why the regen feature will not work with my set up.

In all reality, I am removing the entire system from a forklift - in its entirety. I am fundimemtally removing the forklift from the motor, and replacing it the forklift with a car. The whole time, fundimentally, the controller, wiring, and everything is still attached to the motor.....not changing anything......well, I am removing the pump motor and it's two wires.....no sence in that dragging allong behind, or dangling out of the hood! :

Before I "unbolted" the forklift, the regen worked in it's stock form. When I "replace" the forklift with a car, why wouldn't this regen feture still work? None of the contactors have changed, the circuitry is still the same.

I'm glad you brought up the brush advancement, as I never thought of that. I don't plan on advancing the motor, as I'm only running 48V. 

The only reason I'm pushing for this is due to my logistical situation. I live 1 mile from town (speed limit is half 55MPH, and half 35 - I plan on ignoring the 55MPH....I _know_ that will never happen on 48v!). So I will use a fairly decent amount of charge on the way into town. Once I get there, there is a long down hill. Everything is uphill from the center of town (town is shaped like a bowl, basically).
Yesterday, I went into town, did a good amount of running around, (more than usual) and put on 9 miles. -FWIW.

_*Not *_trying to dispute the thory, or anyone knowledge.....just trying to understand!

Thanx in advance!


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## major (Apr 4, 2008)

crazybry79 said:


> OK, I'm following you.....sort of...
> 
> Bear with me, as I am an electrical novice,
> 
> ...


Hi craz,

O.K. Theory is E=½Mv². As long as your system voltage, current and energy (E) are about the same, it should work  You get too far out of whack on any of those three parameters, and you could see Mr. Zorch stick his ugly head into your motor and ruin your day 

And the other thing which I am concerned about: Do you understand plugging vs regeneration? All these forklift controllers plugged. Few regenerated.

Regards,

major


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## crazybry79 (Jun 15, 2010)

Eww... I dunno who Mr. Zorch is....but he sounds like a mean bugger! 

Well, I am using a 24V GE 6.7" motor (all I know for now) with the original EV100 controller.

I am running a 48V system.

One thing I am not sure on, is if I need a new card for the EV 100 since I am going from 24V to 48V. According to the manual, I am good for 24V to 80V . "24-80VDC"

I do understand the difference between plugging and regen. As I was reading through the manual, there seems to be a direct corelation between the two.
IE: If the forklift is traveling, and the direction switch is reversed, plugging starts. The controller may be programmed to start regen at X amps, and will continue to regen until Y amps. X & Y = 65A - 630A.
Where I get lost (a bit....) the plug can be set to activate from A to B set points, and when B is exceeded, the the regen kicks in from the preset values of X to Y, depending on the throttle position. THAT much, I am slowly figuring out, with some assistance from some forklift techs....I guess I can turn the regen on to start as soon as the plug condition is met (basically using 100% regen, and 0% plug...if that makes sence)

http://www.fsip.biz/Documents/EV100ZX TECH.pdf
Specs are on page 12
Regen settings found on page 77 function 9 & 10
Plug settings found on page 78 Function 16


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