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mossige

Posted: Mar 18, 2012 - 09:23 PM

Joined: May 23, 2003
Posts: 544
Location: NAERBOE, Norway

I have bought an electric car, and I wish to mesure the power the charger draws from the power line, 230V AC, 10A (+/-), 50 Hz.

I have read AVR465, but I think that is to complicate for me, and too accurate for my need. +/- 5% are OK for me.

All I need are a pulse each KWh or WH to feed a PLC.

I think it might be build of a voltage and a current xformer, some, op.amp., may be a log. one.

I am thinking of to use two current xformrt in serial, 1:34 + 1:34, making one 1:1000. This way I will be able to experiment with the neede turns.

I have tried to google, but did not find any use able.

I ask anyone to guide me to an app. note or some thing else use full.

For the current xformers, what core will be appropriate(read: easy available.)

HM

Sad

bobgardner

Posted: Mar 18, 2012 - 09:31 PM

Joined: Sep 04, 2002
Posts: 21257
Location: Orlando Florida

http://search.digikey.com/us/en/product ... ND/2362753

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John_A_Brown

Posted: Mar 19, 2012 - 09:05 AM

Joined: Sep 20, 2003
Posts: 4074
Location: Surrey, England

You can buy something that will do this for about £10, or you could the last time I bought one.
Of course, you may actually want to build it yourself, in which case ignore this post.
http://www.maplin.co.uk/plug-in-electricity-cost-and-usage-calculator-223573

Brutte

Posted: Mar 19, 2012 - 10:58 AM

Joined: Oct 05, 2006
Posts: 2244
Location: Poland

Quote:

I have bought an electric car

Can you (after the measurements) report us how much energy per km your car uses annually? That is:
"This year my electric car has made 12345km using only 4789kWh, in Norway."?

You can buy a regular power meter (16A/230V)with opto-isolated output(opto-transistor, 100Wh/imp) for ~25$. Do not try to reinvent the wheel - just buy one.

Mongooose

Posted: Mar 19, 2012 - 11:29 AM

Joined: Sep 25, 2008
Posts: 112
Location: Alabama Gulf Coast

I would also be very interested in hearing what kind of km per kWh you get.

mossige

Posted: Mar 19, 2012 - 12:40 PM

Joined: May 23, 2003
Posts: 544
Location: NAERBOE, Norway

John_A_Brown wrote:

Yes, but with the lack of pulses to my PLC.

HM

TPE

Posted: Mar 19, 2012 - 02:18 PM

Joined: May 02, 2006
Posts: 319
Location: Norway

Hi.
all meter has "S0" output ( in norway) can you use it to read form your PLC.
a meter is cheap.
Thierry

John_A_Brown

Posted: Mar 19, 2012 - 02:36 PM

Joined: Sep 20, 2003
Posts: 4074
Location: Surrey, England

mossige wrote:

John_A_Brown wrote:

Yes, but with the lack of pulses to my PLC.

HM

Indeed.
But you didn't say what you wanted to do with the PLC, so I thought maybe you just wanted the PLC to count the pulses and display figures.

If you want to do something else, then you should have taken my second piece of advice and ignored the post - and the paradox of simultaneously ignoring the post whilst following advice contained in the post.

LDEVRIES

Posted: Mar 19, 2012 - 08:52 PM

Joined: May 04, 2007
Posts: 3529
Location: Geelong Australia, Home of the "Cats"

mossige wrote:

John_A_Brown wrote:

Yes, but with the lack of pulses to my PLC.

HM

ALDI regularly have 240V 10 Amp power meters for sale for about $15AUS. It will have all the interface electronics in a nice safe enclosure already & you should be able to shoe-horn a MCU & a Bluetooth TRX into it.

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mossige

Posted: Mar 19, 2012 - 11:39 PM

Joined: May 23, 2003
Posts: 544
Location: NAERBOE, Norway

LDEVRIES wrote:

mossige wrote:

John_A_Brown wrote:

Yes, but with the lack of pulses to my PLC.

HM

Sure.
Google: aldi + "power meter" + 230V + 10A

I am not sure this are helpfull.

HM

mossige

Posted: Mar 20, 2012 - 12:31 AM

Joined: May 23, 2003
Posts: 544
Location: NAERBOE, Norway

I wonder why it is so difficult to answer the questione I ask.

I know, it is wiser to buy something ready build, - if I find something satisfying my needs for an reasonable price volum.

For now, I have not found anything, and I do not find your advices use full either. Therefore, I am thinking of building something my self.

HM

KitCarlson

Posted: Mar 20, 2012 - 01:06 AM

Joined: Feb 06, 2009
Posts: 834
Location: TN

There are many prior posts on this subject. You might get some ideas by searching those. The best advise is buy one, it will save you both time and $.

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mossige

Posted: Mar 20, 2012 - 01:15 AM

Joined: May 23, 2003
Posts: 544
Location: NAERBOE, Norway

LDEVRIES wrote:

mossige wrote:

John_A_Brown wrote:

Yes, but with the lack of pulses to my PLC.

HM

Do you have any pointer to one?

HM

LDEVRIES

Posted: Mar 20, 2012 - 01:19 AM

Joined: May 04, 2007
Posts: 3529
Location: Geelong Australia, Home of the "Cats"

Quote:

I am not sure this are helpfull.

ALDI - Where
power meter - What
230V + 10A - Specs
What is not helpful about that?

Quote:

Therefore, I am thinking of building something my self.

Good! Please don't ask for any further suggestions on how to do it, so that we won't be be wasting your precious time again.
Just waste your own time!

bobgardner

Posted: Mar 20, 2012 - 01:42 AM

Joined: Sep 04, 2002
Posts: 21257
Location: Orlando Florida

Did you think I picked out a good current transformer from digikey? That gives you current. Two resistors gives you volts. One line of c gives you watts. I'd output it to a text lcd.

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Last edited by bobgardner on Mar 28, 2012 - 03:25 PM; edited 1 time in total

John_A_Brown

Posted: Mar 20, 2012 - 07:49 AM

Joined: Sep 20, 2003
Posts: 4074
Location: Surrey, England

bobgardner wrote:

Did you think I picked out a good current transformer from digikey? That gives you current. Two resistors gives you volts. One line of c gives you watts. I'd output it a text lcd.

He wants it to feed pulses to a PLC, although we don't know why. I'm sure that if he wanted it on an LCD he would buy one for £10.

Brutte

Posted: Mar 20, 2012 - 11:57 AM

Joined: Oct 05, 2006
Posts: 2244
Location: Poland

John_A_Brown wrote:

He wants it to feed pulses to a PLC

Building a power meter from the scratch is challenging. I do not think those from LIDL guarantee 5% power measurements of switching devices. And since this is going to power a DC/DC for sure, I think such DC/DC is resisitive (with Groetz at input) but not linear, so the higher frequencies influence the measurements.

mossige wrote:

+/- 5% are OK for me.

Mind a 5% accuracy fuel consumption meter is a totally useless device. You will learn nothing from it when it tells you your millage is for example somewhere in between 5 and 5,5 liters of fuel per 100km because you already know it is somewhere in between those values, just listening to the rpm, usually.

LDEVRIES

Posted: Mar 20, 2012 - 12:02 PM

Joined: May 04, 2007
Posts: 3529
Location: Geelong Australia, Home of the "Cats"

Quote:

I think such DC/DC is resisitive (with Groetz at input)

In English that would be a bridge rectifier at the input?

Graetz=Bridge rectifier??

Brutte

Posted: Mar 20, 2012 - 01:33 PM

Joined: Oct 05, 2006
Posts: 2244
Location: Poland

Quote:

In English that would be a bridge rectifier at the input?

http://en.wikipedia.org/wiki/Diode_bridge
Yes, you are right, it is "Graetz", not "Groetz". A diode bridge rectifier.

I think these 230V chargers are powered with a simple 4x Si diode rectifiers, a 1,5V voltage drop will degrade performance only under 1,5/230= 0,65% so it is not worth investing in a more clever rectifier.. But I am not sure about that - I think a 2kW nonlinear DC/DC charger or two could shake all the network in a neighborhood.

mossige

Posted: Mar 20, 2012 - 02:02 PM

Joined: May 23, 2003
Posts: 544
Location: NAERBOE, Norway

Brutte wrote:

Quote:

In English that would be a bridge rectifier at the input?

You are wrong. The charger for my car are a zivan, NG3 - 72V:

http://www.zivanusa.com/NG3BatteryCharger.htm

HM

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