Kill A Watt P4400 on sale

[PeterD]

On Sat, 05 Sep 2009 19:16:23 +0100, "Dave Plowman (News)"
<dave@davenoise.co.uk> wrote:

In article <h7u9lj$8i7$1@news.eternal-september.org>,
William Sommerwerck <grizzledgeezer@comcast.net> wrote:
Those can be fine, accuracy-wise. But of very limited use. After
all, it's not difficult to work out what most appliances cost to run.

When I get around to it, I'm going to put it on my fridge for a few
days. I want to see exactly how many kWh it draws over a week or so. You
can't do that with a clip-on, because refrigerators run intermittently.

That's true - but what action will you take? You can hardly switch it off
to save energy. Unlike heating and aircon. If it's old a new one will
almost certainly be more efficient. But may cost more than it saves.

My sister replaced her old (died) fridge this spring. The old was not
that old, about 6 years, IIRC. The new was a model considered energy
efficient. She did notice a drop in electrical consumption with the
new one, and figured that the new one would have paid for itself in
about 4 to 6 years.

 

[David Nebenzahl]

On 9/5/2009 6:23 AM PeterD spake thus:

On Fri, 04 Sep 2009 16:56:07 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

PeterD wrote:

On Fri, 4 Sep 2009 05:51:31 -0700, "William Sommerwerck"
grizzledgeezer@comcast.net> wrote:

www.superspammingstore.com has the "Kill A Watt" power/energy
meter on sale for less than $19, shipping included. I have two,
and I might buy another. Consumer Reports says it's accurate
within 2 or 3%.

Rush right out in a buying frenzy!

Piss off, spammer.

William isn't a spammer. A lot of techs use that product, or
something similar. You never seem to contribute to this newsgroup, so
why don't you 'piss off'?

Fine... So now spamming is acceptable. There is NO difference between
William's selling the 'Kill A Watt' meter, and that chinese ass who is
selling shoes, other than what the product is.

He's not *selling* it, you idiot.


--
Found--the gene that causes belief in genetic determinism

 

[Jeff Liebermann]

On Sat, 05 Sep 2009 13:11:29 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

It is an inline device:
http://www.p3international.com/products/special/P4400/P4400-CE.html

Some more...

Photo of the insides of the original and the later P4440 versions. The
P4440 is at the bottom:
<http://802.11junk.com/jeffl/pics/drivel/slides/kill-a-watt.html>
The original version has no memory (loses history if unplugged) and
has only 4 buttons on the front. The later version has 5 buttons and
retains usage history until the cap discharges. I don't have a P4460
(EZ) inside photo.

I have about 4 of them, some of which are permanently installed
monitoring the power consumption of various devices. I use 3 more for
distributing the electric power bill on a mountaintop radio site (with
poor weather protection). The main advantage is the low price.
However, the operation of the 5 buttons is not very obvious and I have
to keep a copy of the instructions nearby.

Costco has the P4460 for $27.

Recently, I've been considering alternatives, which seem to have some
advantages, like less button pushing. I have one of these on order:
<http://www.amazon.com/Energy-Meter-LCD-Display-EM100/dp/B000RKVK52>
Black and Decker also makes one, but it's overpriced at about $100.:
<http://www.blackanddecker.com/Energy/products.aspx>

As for accuracy, the P4400 models that I have seem fairly accurate,
even at low levels. I don't have an easy way to calibrate these,
especially with odd power factors. My mechanical disc power meter and
the numbers from a P4400 were quite close when I tested both in series
running only a refridgerator for a month.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Sat, 05 Sep 2009 10:25:47 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

A clamp on ammeter is fine for some uses. It doesn't log power
consumption. It is a tool intended for electricians, and most do not
give accurate readings on anything other than a pure resistive load.
Reading the actual load of a switch mode power supply requires a good
RMS converter in the meter. The same as the ones mate for the new
electronic watt hour meters. Its a poor worker who doesn't understand
his tools, yet defends bad work.

I use both clamp-on and inline meters. The clamp-on is best for
troubleshooting while the inline is best for monitoring. My no-name
Chinese clamp-on meter does accumulate usage (logging), but does not
have the power factor correction I need for dealing with inductive
loads (motors), or badly designed switchers. The inline can also do
cost calculations, which is something my customers can see and
understand.

However, the big advantage is that I can buy the inline meter for
about $27, do my song and dance for the customer, and then sell it to
him for about twice that. It also give the customer the impression
that I'm tryting to save him money by monitoring his electricity
usage. It's design makes it acceptable for leaving it in place for
monitoring, while a clamp-on meter plus inline cord splitter, would be
an ugly mess.

Note: I'm not an electrician. This week, I fix computahs. Computer
owners often want to know how much power their PC or monitor is
burning. Hmmm... I just bought myself a new desktop and forgot to
measure it.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[David Nebenzahl]

On 9/5/2009 11:50 AM Jeff Liebermann spake thus:

On Sat, 05 Sep 2009 13:11:29 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

It is an inline device:
http://www.p3international.com/products/special/P4400/P4400-CE.html

Some more...

Photo of the insides of the original and the later P4440 versions. The
P4440 is at the bottom:
http://802.11junk.com/jeffl/pics/drivel/slides/kill-a-watt.html

So how does this thing work?

It looks like the power just passes straight through from plug to socket
over there on the left. Is there a current transformer in there
somewhere? What about that half-loop thingy on top? And what's that
semicircular thing doing between the power prongs above the ground
connector?


--
Found--the gene that causes belief in genetic determinism

 

[William Sommerwerck]

When I get around to it, I'm going to put it on my fridge for a few
days. I want to see exactly how many kWh it draws over a week or so.
You can't do that with a clip-on, because refrigerators run
intermittently.

That's true - but what action will you take? You can hardly switch it off
to save energy. Unlike heating and aircon. If it's old a new one will
almost certainly be more efficient. But may cost more than it saves.

Correct. But I feel my electric bill is too high, and I need some evidence
to argue with the utility. I intend to measure everything in my condo.

 

[Jeff Liebermann]

On Sat, 05 Sep 2009 12:09:18 -0700, David Nebenzahl
<nobody@but.us.chickens> wrote:

On 9/5/2009 11:50 AM Jeff Liebermann spake thus:

On Sat, 05 Sep 2009 13:11:29 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

It is an inline device:
http://www.p3international.com/products/special/P4400/P4400-CE.html

Some more...

Photo of the insides of the original and the later P4440 versions. The
P4440 is at the bottom:
http://802.11junk.com/jeffl/pics/drivel/slides/kill-a-watt.html

So how does this thing work?

It works quite well.

The actual device is made by Prodigit in China:
<http://www.prodigit.com>
<http://www.prodigit.com/index.php?lang=en&op=product&pro_num=1051>
<http://www.prodigit.com/index.php?lang=en&op=product&pro_num=1052>

It looks like the power just passes straight through from plug to socket
over there on the left. Is there a current transformer in there
somewhere?

I haven't ripped it apart and traced out a schematic (yet). As near
as I can guess(tm), the big half loop near the power jack is a low
value series resistor. There's no current xformer inside. The big
green capacitor is probably AC line coupling for measuring the
voltage. The LM324/LM2902 is probably setup as input sections of an
instrumentation amplifier to float and isolate the AC line from the
rest of the circuitry:
<http://en.wikipedia.org/wiki/Instrumentation_amplifier>
The chip on the display (right) section is apparently a proprietary
ASIC and probably handles some of the analog circuitry, the A/D
converters, and display functions.

What about that half-loop thingy on top?

Series resistor.

And what's that
semicircular thing doing between the power prongs above the ground
connector?

It's part of the plastic case. My guess(tm) is that it's to align the
power jack connectors to the case. Since there are no mounting
screws, and the PCB is attached to the case with hot melt glue,
something like that is required. No clue why the strange shape as
some round holes would have done as well. My guess(tm) is that if one
of the brass power jacks became detached from the PCB, it would not
lean into the opposing connector as it is blocked by the plastic
thing.



--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Sat, 5 Sep 2009 11:11:09 -0700, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

Those can be fine, accuracy-wise. But of very limited use. After
all, it's not difficult to work out what most appliances cost to run.

When I get around to it, I'm going to put it on my fridge for a few days. I
want to see exactly how many kWh it draws over a week or so. You can't do
that with a clip-on, because refrigerators run intermittently.

Yes you can with the proper adapter.
<http://support.radioshack.com/support_meters/doc21/21584.htm>
The Radio Shock inline current sensor is the device on the right. It's
normally NOT sold seperately. It consists of 1 turn and 10 turn loops
inside a plastic case, wired in series with the AC line. The clamp-on
meter clips into either the 1 turn hole for fairly large currents, or
the 10 turn hole for a 10x current multiplier. You could easily build
one of these if you can't find one to buy.

However, there's a problem. Your fridge is an inductive load, which
will require power factor correction to obtain the same current as
measured by the typical disc type electric power meter. You can't do
that with a typical clamp-on ammeter. You can do that with a wall
mounted inline power meter.

Also, watch out for refrigerators that have self-defrosters. Some are
on demand, while others are on a timer. The defroster sucks LOTS of
power and will be a big part of the electric bill. Same with
on-demand ice cube makers.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[David Nebenzahl]

On 9/5/2009 12:37 PM Jeff Liebermann spake thus:

On Sat, 05 Sep 2009 12:09:18 -0700, David Nebenzahl
nobody@but.us.chickens> wrote:

So how does this thing work?

It looks like the power just passes straight through from plug to
socket over there on the left. Is there a current transformer in
there somewhere?

I haven't ripped it apart and traced out a schematic (yet). As near
as I can guess(tm), the big half loop near the power jack is a low
value series resistor.

Ah, so. So the loop must be connected on one side to the incoming hot
line, and on the other side to the outgoing hot line. Then the unit
measures the voltage across the loop (resistor) proportional to current.
Right?


--
Found--the gene that causes belief in genetic determinism

 

[Jeff Liebermann]

On Sat, 05 Sep 2009 19:16:23 +0100, "Dave Plowman (News)"
<dave@davenoise.co.uk> wrote:

That's true - but what action will you take? You can hardly switch it off
to save energy. Unlike heating and aircon. If it's old a new one will
almost certainly be more efficient. But may cost more than it saves.

"Saving energy when using refrigerators and freezers"
<http://www.energyrating.gov.au/rfuse.html>

What I did initially was:
1. Cleaned the crap out from behind and under the fridge so that the
radiator coils can efficiently radiate.
2. Moved the fridge away from the wall to improve air flow.
3. Disarmed the self-defrost timer and defrosted it manually (pull
the plug and chisle out the ice).

My guess(tm) is about a 20% decrease in energy costs, mostly because
it was running more efficiently.

The above fridge was sufficiently old that the compressor was starting
to make noises when running. So, I decided I could live with a much
smaller fridge and purchased a small "bar type" cheapo for $120. I
haven't bothered to calculate the savings, but I vaguely recall my
monthly electric bill at the time dropped about $20.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[whit3rd]

On Sep 5, 11:00 am, "Dave Plowman (News)" <d...@davenoise.co.uk>
wrote:

Ah - right. Those can be fine, accuracy wise. But of very limited use.
After all it's not difficult to work out what most appliances cost to run..

Don't think small! I've used power meters to do LOTS of tuning
operations.
Consider an AB power stage, where 50W peak is available; you might
allow 2W of quiescent power dissipation, and that means (under no-load
conditions) cranking the final stage bias fully down, powering up the
unit,
and watching the power meter while slowly tweaking up the
bias pot. When it gets to x + 2W, you're done.

RF output power is awkward to measure, too; tuning a power
oscillator with a power meter on the AC input is ... luxurious.
Look, ma! No more RF burns!

And that little kill-a-watt is a much nicer way to find out what the
(duty-cycle-according-to-humidistat) dehumidifier really costs to
run down in the basement, than an A/B comparison on 2006 and 2007
electric utility bills. I did the electric bill comparison first.
Wish
it was the other way around.

 

[Jeff Liebermann]

On Sat, 05 Sep 2009 13:18:10 -0700, David Nebenzahl
<nobody@but.us.chickens> wrote:

On 9/5/2009 12:37 PM Jeff Liebermann spake thus:

On Sat, 05 Sep 2009 12:09:18 -0700, David Nebenzahl
nobody@but.us.chickens> wrote:

So how does this thing work?

It looks like the power just passes straight through from plug to
socket over there on the left. Is there a current transformer in
there somewhere?

I haven't ripped it apart and traced out a schematic (yet). As near
as I can guess(tm), the big half loop near the power jack is a low
value series resistor.

Ah, so. So the loop must be connected on one side to the incoming hot
line, and on the other side to the outgoing hot line. Then the unit
measures the voltage across the loop (resistor) proportional to current.
Right?

Exactly. It's quite simple.

There's usually a patent on something like this. Digging....bingo:

"Electric adapter with display unit"
<http://www.google.com/patents?id=G3MDAAAAEBAJ&dq=6095850>
Nice explanation with a blockish diagram. My guess(tm) was wrong
about half the instrumentation amp. It's even cruder than I thought.

Some additional drivel on patent litigation:
<http://greenpatentblog.com/2008/12/24/smartlabs-enjoined-parties-smart-management-focuses-issues-in-energy-meter-litigation/>
I'm not sure of the final judgement in the case, but the infringing
UPM Marketing device is probably the one I have on order and are being
sold again by Smarthome:
<http://www.smarthome.com/_/Cable_Structured_Wiring/Tools/UPM_Marketing/_/v/1P9/1wN/nav.aspx>


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Dave Plowman (News)]

In article <h7ue92$cdu$1@news.eternal-september.org>,
William Sommerwerck <grizzledgeezer@comcast.net> wrote:

When I get around to it, I'm going to put it on my fridge for a few
days. I want to see exactly how many kWh it draws over a week or so.
You can't do that with a clip-on, because refrigerators run
intermittently.

That's true - but what action will you take? You can hardly switch it
off to save energy. Unlike heating and aircon. If it's old a new one
will almost certainly be more efficient. But may cost more than it
saves.

Correct. But I feel my electric bill is too high,

Know what you mean. ;-)

and I need some evidence to argue with the utility.

No method of getting them to check the meter accurately - IIRC in the UK
they fit a second one to check the first.

I intend to measure everything in my condo.

In my case I hadn't really noticed how much lighting load I had - and
leaving lights on - until the price doubled. My house and water heating
are gas.

--
*Why isn't there mouse-flavoured cat food?

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[William Sommerwerck]

Also, watch out for refrigerators that have self-defrosters.
Some are on demand, while others are on a timer. The
defroster sucks LOTS of power and will be a big part of
the electric bill.

I intend to measure the energy over a week or so. That should average out
things.

 

[David Nebenzahl]

On 9/4/2009 5:51 AM William Sommerwerck spake thus:

www.supermediastore.com has the "Kill A Watt" power/energy meter on sale for
less than $19, shipping included.

Not quite. Singly they're $21.99. $19.99 ea. for 3 or more.

http://www.supermediastore.com/kilwateldet1.html


--
Found--the gene that causes belief in genetic determinism

 

[William Sommerwerck]

www.supermediastore.com has the "Kill A Watt" power/energy
meter on sale for less than $19, shipping included.

Not quite. Singly they're $21.99. $19.99 ea. for 3 or more.
http://www.supermediastore.com/kilwateldet1.html

In an earlier post, I indicated that you need a code...

94EL15P

 

[CaltechPhD]

On Sep 5, 7:25 am, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

   It appears that you have very low reading comprehension.  Some places
want over $50 for the item. He found a good deal, and shared it.  I've
know William online for about ten years on another newsgroup.  We've had
some disagreements, but over all, he's a good guy.  He even rallied some
of the regulars in that group to help me when the VA refused some
medical care I needed, to survive.

Let's be real: any one of us would have no problems finding the
product if we wanted it, it was unnecessary to spam it.

   Lets get real:  You don't know what you are talking about.

So since so many of William's friends say to 'piss off' or otherwise
bugger off and go away, so be it. I'll not critize spammers again here
in this group.

   Spam is selling your goods, not telling others you found a good deal.
You, on the other hand are quickly becoming a troll. I haven't seen any
of William's friends telling him to piss off.  Just the groups usual
malcontents with another wild hair up their ass.

As to 'techs using the product' fine. I use a clamp-on amp meter,
works well for my needs.

   A clamp on ammeter is fine for some uses. It doesn't log power
consumption.  It is a tool intended for electricians, and most do not
give accurate readings on anything other than a pure resistive load.
Reading the actual load of a switch mode power supply requires a good
RMS converter in the meter.  The same as the ones mate for the new
electronic watt hour meters.  Its a poor worker who doesn't understand
his tools, yet defends bad work.

--
You can't have a sense of humor, if you have no sense!- Hide quoted text -

- Show quoted text -

 

[CaltechPhD]

On Sep 5, 7:25 am, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

 I've
know William online for about ten years on another newsgroup.
Wow! I claim that I first met him about 44 years ago.

 

[William Sommerwerck]

"CaltechPhD" <josephfeng@alumni.caltech.edu> wrote in message
news:d06ec50b-f059-49e3-855a-b5457b0faa2a@g1g2000pra.googlegroups.com...
On Sep 5, 7:25 am, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

I've know William online for about ten years on another newsgroup.

Wow! I claim that I first met him about 44 years ago.

It's possible. I attended Caltech briefly then (Fall, 1965). I was a total
shmuck then, and I apologize.

I apologize for not remembering your name, but it just doesn't ring a bell.

 

[Meat Plow]

On Sat, 5 Sep 2009 11:11:09 -0700, "William Sommerwerck"
<grizzledgeezer@comcast.net>wrote:

Those can be fine, accuracy-wise. But of very limited use. After
all, it's not difficult to work out what most appliances cost to run.

When I get around to it, I'm going to put it on my fridge for a few days. I
want to see exactly how many kWh it draws over a week or so. You can't do
that with a clip-on, because refrigerators run intermittently.

A refridgerator in a natural gas heated/hot water/cooking home is the
#1 watt bandit. My 10 something CUF fridge all of 3 years old consumes
30% of my total usage on a normal setting. Just two of us living here
so it's easy to gauge usage otherwise. Lighting is CFL. Only other
watt magnet is the big screen which is on 6 hours a day (rear
projector) and a P4 computer on 24/7. Plus security lighting outside
in the form of 3 100 watt CFLs for 10 hours a day. This equals about a
$65/mo bill.