Basic KWh Power Meters?

[Jase Roberts]

I'm looking for a basic power meter that would allow me to measure how
much electricity my major home appliances use. I've already put
together a little adaptor that lets me insert my multimeter into the
circuit to do instantaneous readings on lower wattage things (e.g. my
computer). However, this will only work up to 10A, and the
instantaneous readings are really only useful for estimating power
consumption of things that have fairly constant draw.

What I'm hoping to find is something like a miniature version of the
electric meter you find outside your house. It would have a cord to
plug into the wall socket (both 110V & 220V would be ideal), and a
socket on the unit to plug in the appliance. You'd then leave it in
place for a month or so and see what the cumulative usage has been.
This would be ideal for checking consumption on appliances like a
refrigerator, microwave, washer, etc that have intermittant spikes of
high usage followed by periods of no draw.

Is it possible to buy a commercial version of a meter like this? If
not, any suggestions of what components one could use to build one?
What about buying a used household meter (big dials and all) and
wiring that up?

Thanks, Jase

 

[JW]

On 4 Aug 2004 11:45:52 -0700 usenet@jaseroberts.net (Jase Roberts) wrote
in Message id: <af54826d.0408041045.6dc17cbc@posting.google.com>:

I'm looking for a basic power meter that would allow me to measure how
much electricity my major home appliances use. I've already put
together a little adaptor that lets me insert my multimeter into the
circuit to do instantaneous readings on lower wattage things (e.g. my
computer). However, this will only work up to 10A, and the
instantaneous readings are really only useful for estimating power
consumption of things that have fairly constant draw.

What I'm hoping to find is something like a miniature version of the
electric meter you find outside your house. It would have a cord to
plug into the wall socket (both 110V & 220V would be ideal), and a
socket on the unit to plug in the appliance. You'd then leave it in
place for a month or so and see what the cumulative usage has been.
This would be ideal for checking consumption on appliances like a
refrigerator, microwave, washer, etc that have intermittant spikes of
high usage followed by periods of no draw.

Is it possible to buy a commercial version of a meter like this? If
not, any suggestions of what components one could use to build one?
What about buying a used household meter (big dials and all) and
wiring that up?

How about:
http://www.gaiam.com/retail/product.asp?product_id=25819

 

[JW]

On 4 Aug 2004 11:45:52 -0700 usenet@jaseroberts.net (Jase Roberts) wrote
in Message id: <af54826d.0408041045.6dc17cbc@posting.google.com>:

I'm looking for a basic power meter that would allow me to measure how
much electricity my major home appliances use. I've already put
together a little adaptor that lets me insert my multimeter into the
circuit to do instantaneous readings on lower wattage things (e.g. my
computer). However, this will only work up to 10A, and the
instantaneous readings are really only useful for estimating power
consumption of things that have fairly constant draw.

Or even
http://www.gaiam.com/retail/product.asp?catalog%5Fname=gai&category%5Fname=l3%5FMetersAdvanced&product%5Fid=25818

It's cheaper.

 

[Jase Roberts]

Just to make sure it's clear, my ultimate goal is to figure out how
much various items in my house contribute to my monthly electricity
bill. As I said, I've been able to make decent estimates on low
power, high use things (computer, fans, dehumidifier, etc). I want
something to measure the high power, low use items (refrigerator,
microwave, washer, etc.) over a reasonable period of time.

One interesting thing I've already noted is that I pay a few bucks a
month for things that are supposed to be "off". For example, a TV,
VCR, stereo, and anything with an AC->DC wall adapter all use some
amount of power even when you're not using them. Sure, it's only a
few bucks a month, but spending $30/year to power things that are
supposed to be "off". -Jase

 

[Jase Roberts]

Damn, Google is good! Basic searches before I posted didn't turn up
much (too many results with these common words), but targeted ads at
the top of the original posting via Google Groups
(http://groups.google.com/groups?th=527b3a626a758ffb) are spot on.

http://www.twacomm.com/Catalog/Model_P4400.htm seems to fit the bill,
although it's not clear to me if it does instantaneous readings and
extrapolates, or actually measures usage cumulatively.

http://www.theenergydetective.com/frameset.asp is similar, but clearly
more complex (and expensive).

Other suggestions? How about the idea a home-brew using an old
household meter?

 

[Roger Gt]

"Jase Roberts" <usenet@jaseroberts.net> wrote in message
news:af54826d.0408041045.6dc17cbc@posting.google.com...
: I'm looking for a basic power meter that would allow me to
measure how
: much electricity my major home appliances use.

<snip>

: Is it possible to buy a commercial version of a meter like this?
If
: not, any suggestions of what components one could use to build
one?
: What about buying a used household meter (big dials and all) and
: wiring that up? Thanks, Jase


Not with such Big dials. But try

http://shop.store.yahoo.com/supermediastore/kilwateldet1.html

$25 is a good price, I have two I use around the house for
auditing, they work very well!

Roger Gt

 

[normanstrong]

"JW" <none@dev.nul> wrote in message
news:78b4h0pfaopf1gh40hbuo6r8q7keba3m87@4ax.com...

On 4 Aug 2004 11:45:52 -0700 usenet@jaseroberts.net (Jase Roberts)
wrote
in Message id: <af54826d.0408041045.6dc17cbc@posting.google.com>:

I'm looking for a basic power meter that would allow me to measure
how
much electricity my major home appliances use. I've already put
together a little adaptor that lets me insert my multimeter into
the
circuit to do instantaneous readings on lower wattage things (e.g.
my
computer). However, this will only work up to 10A, and the
instantaneous readings are really only useful for estimating power
consumption of things that have fairly constant draw.

Or even

http://www.gaiam.com/retail/product.asp?catalog%5Fname=gai&category%5Fname=l3%5FMetersAdvanced&product%5Fid=25818

It's cheaper.

I have one of these units. It has a serious flaw. If the power fails
for even a second, it loses its memory, and your reading of
accumulated watthours is gone. There should be a battery in it to
maintain its memory.

Norm Strong