# Re: [EVDL] Curtis controller voltage questions



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Curtis controller voltage questions*

11:00 P.M EDT
Hi Markus;

> thanks a lot for the writeup. You are right I do not have the
> application notes for the 1221R. I managed to get a connection diagram
I can photocopy and mail, or scan and email, a copy to you if interested, 
when I could find time in a few days.

> Anyhow, this info is great. I yet have to find the place where the pots
> are. One end of my 1221R is just a piece of flat metal, with a sticker
The access holes to the pots are on the long sides, behind hole filling 
plugs that you unscrew for access through the hole, using a small 
screwdriver to adjust.

> The info you gave lets me feel more confident that I can try to up the
> voltage a bit. I will try it in 12V steps and hope the overvoltage
> protection kicks in before something breaks. I have been driving at 90V
I was trying to discourage you from doing this on my last email when I sent 
the boost diagram!
"You are right to be afraid. Don't use more than 1 12V battery. Let's not
be greedy and risk trouble!
Also, if you are using the regen capability of the 1221R, with a reversing
contactor installed, be careful that you don't bring the voltage up too high
and have the 1221R do an over-voltage shutdown which will open the reversing
contactor under load and damage the NC contacts. "
The controller likely has a 159V withstand rating and an over-voltage 
turn-off at around 105V. If you boost by 12V or less while under load, you 
will not likely exceed 105V total under that condition. If you boost by 24V 
you probably will exceed 105V sometimes and cause a shut-off under load 
which would open a regen reversing contactor - bad.

Best Regards,

Doug

----- Original Message ----- 
From: "Markus Lorch" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Monday, August 06, 2007 3:44 PM
Subject: Re: [EVDL] Curtis controller voltage questions


> Hi Doug,
>
> thanks a lot for the writeup. You are right I do not have the
> application notes for the 1221R. I managed to get a connection diagram
> from Carlos but thats all I got. Curtis was unable to provide me with
> any information last year when I talked to them on the phone etc.
>
> Anyhow, this info is great. I yet have to find the place where the pots
> are. One end of my 1221R is just a piece of flat metal, with a sticker
> indicating the technical specs, the other has the power lugs and an
> adapter for the pots (one throttle, one regen) and the control wires for
> the contactors and key switch. Mine is the 12V control side version.
> I have not yet removed the controller from the car. are the pots on the
> bottom of the controller where it is mounted to the heat sink?
>
>
> The info you gave lets me feel more confident that I can try to up the
> voltage a bit. I will try it in 12V steps and hope the overvoltage
> protection kicks in before something breaks. I have been driving at 90V
> nominal which is about 100V with full batteries and 104V during charging
> (I have old gel cells that I charge only to 2.31V/Cell instead of the
> 2.35 that is recommended for new batteries of this type.) It looks like
> my regen voltage is set to 105V as this is the peak I see when breaking
> at slightly higher speeds (up to 150A).
>
> I will let you know what I find out and if I end up blowing up my curtis
> or if it will work with 120V during accelleration and 90V during regular
> driving and breaking.
>
> Markus
>
> ------
>
> It sounds like you don't have the "Application notes" manual for the 1221R
> controller. According to the manual, there are 1221R models at 36, 48, 
> 60,
> 72, 84, 96, 108 and 120V, shown in a table of spec values. There are 
> made
> in 2 versions: 12V isolated and non-isolated that use the battery pack
> voltage for control and and contactor coils. The "overvoltage point" is
> listed as 159V for all the models from 84V to 120V, possibly because they
> all have 160V rated capacitors. It may be that the only difference 
> between
> 84V to 120V models is the fixed resistor value used to set the range of
> adjustment of the regen charging voltage. That charging range is shown as
> 92-105V for the 84V model.
>
> The 1221R has 4 externally adjustable pots: Charging voltage adjustment is
> on one side and the regen current, current limit and acceleration pots are
> on the other side. You can wire a remotely located pot for manual or 
> brake
> pedal activated control of the maximum regen current.
>
> >> >> 84v is an unusual nominal voltage; was your controller specially
> built
> >> >> for some OEM that wanted this voltage?
> 84V is a common fork lift battery pack voltage in Europe, and was used for
> the electric version of Skoda Favorit cars (that came with an SCR type
> regen
> controller).
>
> Best Regards,
>
> Doug
>
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