# [EVDL] Curtis 1231C-86xx @ 168V



## EVDL List (Jul 27, 2007)

Greetings,
We are currently running a 144V pack with a Curtis 1231C-86xx (96-144V spec)
and ADC Motor and "all systems are go". We would like to increase our range
by adding 2 more Optima D31's in series, thereby increasing the nominal pack
voltage to 168V. Is anyone out there running the same controller beyond the
specified input voltage? Will it handle the increased potential? Any
insight is greatly appreciated.

Martin Emde
Seabury Hall
www.seaburyhall.org/engineering
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## EVDL List (Jul 27, 2007)

> On 10 Oct 2007 at 14:26, martin emde wrote:
> 
> > We are currently running a 144V pack with a Curtis 1231C-86xx (96-144V spec)
> > and ADC Motor and "all systems are go". We would like to increase our range
> ...


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## EVDL List (Jul 27, 2007)

> martin emde wrote:
> > Greetings, We are currently running a 144V pack with a Curtis
> > 1231C-86xx (96-144V spec) and ADC Motor and "all systems are go". We
> > would like to increase our range by adding 2 more Optima D31's in
> ...


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## EVDL List (Jul 27, 2007)

Martin and All,
I had written the response below earlier today, but decided to wait for others to
chime in. Unlike Lee's Halloween voice, I'll be that other dark voice that says, "it is OK", but:

I'm thinking that this should not be a problem, IF you have a contactor on both sides of the battery pack to remove the controller while charging, which you should have anyway. A charger for a 144V pack could peek at 194V (2.7 VPC), so they use 200V components in the controller, and label it as 144V maximum pack voltage. A charger for a 168V pack could peak at 227V, which could injure the controller! Also, just after charging, you must make sure that the pack voltage has dropped below 200 volts before precharging the controller! 
Hope this helps...
Suck Amps,
BB

>Date: Wed, 10 Oct 2007 14:26:24 -1000
>From: "martin emde" <[email protected]>
>Subject: [EVDL] Curtis 1231C-86xx @ 168V
>To: [email protected]
>Message-ID:
>	<[email protected]>
>Content-Type: text/plain; charset=ISO-8859-1
>
>Greetings,
>We are currently running a 144V pack with a Curtis 1231C-86xx (96-144V spec)
>and ADC Motor and "all systems are go". We would like to increase our range
>by adding 2 more Optima D31's in series, thereby increasing the nominal pack
>voltage to 168V. Is anyone out there running the same controller beyond the
>specified input voltage? Will it handle the increased potential? Any
>insight is greatly appreciated.
>
>Martin Emde
>Seabury Hall
>www.seaburyhall.org/engineering
>
>

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## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

Let me try to explain why 144V pack is really the absolute max
you want to run this controller at, in case someone may be
tempted to try adding one more battery to get to 156V:

After charging a 144V pack, even after waiting several hours,
the batteries can still be at 13.25V each, total 186V for the
pack.
The internal component for the Curtis are very likely the
standard 200V type, which would leave 14V of headroom or
so it seems - enough to add another battery?
I recommend you find a high-speed memory oscilloscope and
hook it up to the motor output, preferably hooking it up
right at the pins coming out of the FETs, then try a tiny 
bit of trottle and see what the voltage does.
The theory says that you should see a square wave output to
the motor, switching from pack voltage to ground many times
per second. But that is theory.
What you see in practice, is that the voltage across the FET
rises not to pack voltage but many volts higher (overshoot),
then quickly comes back and levels out at pack voltage.
The reason it does that is because the supply and the load
have inductance, causing the current to flow a little longer
after the voltage has disappeared.
Dependent on how short or how long the wires between the FET
and the nearest capacitor is, dependent on how good this
capacitor is, dependent on how fast the current switches and
dependent on how large the current is - that overshoot can be
easily be up to 10% of the switching voltage.
Now add that to the pack voltage of a freshly charged pack:
186 + 19 = 205V.
Do you see that the Curtis is already in the danger done from
breaking down its FETs in a large ball of smoke, simply from
the overshoot spikes every time the FETs turn off (many
thousand times per second) on a 144V pack, so they do not 
need you to push them over the edge by adding another battery
and peaking them to 220V on a 200V part...

Hope this clarifies,

Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Dave (Battery Boy) Hawkins
Sent: Thursday, October 11, 2007 4:02 PM
To: [email protected]
Subject: Re: [EVDL] Curtis 1231C-86xx @ 168V

Martin and All,
I had written the response below earlier today, but decided to wait for others to chime in. Unlike Lee's Halloween voice, I'll be that other dark voice that says, "it is OK", but:

I'm thinking that this should not be a problem, IF you have a contactor on both sides of the battery pack to remove the controller while charging, which you should have anyway. A charger for a 144V pack could peek at 194V (2.7 VPC), so they use 200V components in the controller, and label it as 144V maximum pack voltage. A charger for a 168V pack could peak at 227V, which could injure the controller! Also, just after charging, you must make sure that the pack voltage has dropped below 200 volts before precharging the controller! 
Hope this helps...
Suck Amps,
BB

>Date: Wed, 10 Oct 2007 14:26:24 -1000
>From: "martin emde" <[email protected]>
>Subject: [EVDL] Curtis 1231C-86xx @ 168V
>To: [email protected]
>Message-ID:
>	<[email protected]>
>Content-Type: text/plain; charset=ISO-8859-1
>
>Greetings,
>We are currently running a 144V pack with a Curtis 1231C-86xx (96-144V 
>spec) and ADC Motor and "all systems are go". We would like to 
>increase our range by adding 2 more Optima D31's in series, thereby 
>increasing the nominal pack voltage to 168V. Is anyone out there 
>running the same controller beyond the specified input voltage? Will 
>it handle the increased potential? Any insight is greatly appreciated.
>
>Martin Emde
>Seabury Hall
>www.seaburyhall.org/engineering
>
>

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http://lists.sjsu.edu/mailman/listinfo/ev

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## EVDL List (Jul 27, 2007)

Cor, could you re-look at your math here? 13.25 * 12 = 159V for a 144V 
pack. 186V is 13.25 for a 168V (14-battery) pack. 

Bill Dennis

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## EVDL List (Jul 27, 2007)

From: Bill Dennis
> Cor, could you re-look at your math here? 13.25 * 12 = 159V for a
> 144V pack. 186V is 13.25 for a 168V (14-battery) pack.

A better way to look at it is that your charger will take each 12v battery up to about 15v at the end of a charge cycle. 12 x 15v = 180v. If you leave your controller connected while charging, it is exposed to this full voltage. Even if your controller is disconnected while charging, when you stop charging and start to drive, the battery voltage won't have had time to fall much, so the controller still gets hit with most of this.

--
"Excellence does not require perfection." -- Henry James
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net

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