# [EVDL] emeter voltage prescaler 0-500 vdc



## EVDL List (Jul 27, 2007)

Hello

I have on of those emeter "voltage prescaler 0-500 vdc"

Is there a way to test to make sure it works ok?

I seems only knock off about 10% of the voltage ...


thanks
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## EVDL List (Jul 27, 2007)

What emeter is it designed for?

A prescaler is a resistor that is exactly 9x the resistance of the meter its
intended to be used with.

The volt meter you used to test it with is perhaps 1/9th the resistance of
the prescaler?

Matt 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of m gol
Sent: Sunday, 15 February 2009 2:56 PM
To: Electric Vehicle Discussion List
Subject: [EVDL] emeter voltage prescaler 0-500 vdc

Hello

I have on of those emeter "voltage prescaler 0-500 vdc"

Is there a way to test to make sure it works ok?

I seems only knock off about 10% of the voltage ...


thanks
_______________________________________________
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http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev



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6:29 PM


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## EVDL List (Jul 27, 2007)

link 10 emeter...

I would think it would take the voltage down more than 10%?



> matt <[email protected]> wrote:
> 
> > What emeter is it designed for?
> >
> ...


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## EVDL List (Jul 27, 2007)

How did you connect it and if you can,
please measure the resistance of the
pre-scaler (it is really only 1 resistor) 

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of m gol
Sent: Sunday, February 15, 2009 2:50 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] emeter voltage prescaler 0-500 vdc

link 10 emeter...

I would think it would take the voltage down more than 10%?



> matt <[email protected]> wrote:
> 
> > What emeter is it designed for?
> >
> ...


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## EVDL List (Jul 27, 2007)

Do you mean by this that it reads only 10% of the pack voltage? You will 
need to ignore the decimal point, if it is a Link-10 (used to be E-meter); 
that is, as I recall, the only downside to using it.

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [email protected]


----- Original Message ----- 
From: "m gol" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Saturday, February 14, 2009 9:56 PM
Subject: [EVDL] emeter voltage prescaler 0-500 vdc


> Hello
>
> I have on of those emeter "voltage prescaler 0-500 vdc"
>
> Is there a way to test to make sure it works ok?
>
> I seems only knock off about 10% of the voltage ...
>
>
> thanks
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>


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## EVDL List (Jul 27, 2007)

> m gol wrote:
> 
> > I would think it would take the voltage down more than 10%?
> 
> ...


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## EVDL List (Jul 27, 2007)

> Joe wrote:
> 
> > Do you mean by this that it reads only 10% of the pack
> > voltage? You will need to ignore the decimal point, if it is
> ...


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## EVDL List (Jul 27, 2007)

I meant DMM.

Is there a way to test the voltage drop on the prescaler before hooking it
up with the emeter.



> Jeff Shanab <[email protected]> wrote:
> 
> > > Hello
> > >
> ...


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## EVDL List (Jul 27, 2007)

With a multimeter you can measure the resistance
of the Emeter's voltage sense input (pack voltage) 
and the resistance of the prescaler resistor.

For example, if the Emeter has 100 kOhm resistance
then the prescaler must be exactly 9 times higher or
900 kOhm so that the total resistance of Emeter +
prescaler equals 1 MOhm (1 million Ohms) and the
current through the Emeter at 10x the input voltage
is equal to the current without prescaler at 1/10
of the voltage now.
In other words: the decimal point has shifted a position.
For example with a 288V pack, the Emeter sees 28.8 Volts.
The software has been adapted to multiply the input by 10.

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of m gol
Sent: Monday, February 16, 2009 10:36 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] emeter voltage prescaler 0-500 vdc

I meant DMM.

Is there a way to test the voltage drop on the prescaler before hooking
it
up with the emeter.

On Mon, Feb 16, 2009 at 7:16 AM, Jeff Shanab <[email protected]>


> wrote:
> 
> > > Hello
> > >
> ...


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