Anybody familiar with them? Is the "EZ" (model P4460) worth an
extra $15 over model P4400?

I want to see how much electricity my freezers, TV sets, computers,
etc are *really* using, plus check the frequency stability of my
portable generator and that little inverter than I mounted in my truck.

Thanks,
Bob

"zxcvbob" wrote in message
...
Anybody familiar with them? Is the "EZ" (model P4460) worth an extra $15
over model P4400?

I want to see how much electricity my freezers, TV sets, computers, etc
are *really* using, plus check the frequency stability of my portable
generator and that little inverter than I mounted in my truck.

Thanks,
Bob

You may want to get on the Lee Valley mailing list. They had that model as
a special last week (now sold out) for $20.
www.leevalley.com

zxcvbob wrote:
Anybody familiar with them? Is the "EZ" (model P4460) worth an
extra $15 over model P4400?

I want to see how much electricity my freezers, TV sets, computers,
etc are *really* using, plus check the frequency stability of my
portable generator and that little inverter than I mounted in my
truck.

The "EZ" has two enhanced features over the basic model:

1. You can enter your KWH rate and it will tell you how much - in dollars
and cents - the reading cost, and
2. Has a battery backup so it doesn't reset when the power goes off.

If you don't know how to multiply, or do not have access to a calculator, #1
may be necessary. If you want to accumulate readings over a power outage
situation, #2 might be a help.

Neither "enhancement" seems useful for the needs you have.

On Oct 25, 6:47*am, "HeyBub" wrote:
zxcvbob wrote:
Anybody familiar with them? *Is the "EZ" (model P4460) worth an
extra $15 over model P4400?

I want to see how much electricity my freezers, TV sets, computers,
etc are *really* using, plus check the frequency stability of my
portable generator and that little inverter than I mounted in my
truck.

The "EZ" has two enhanced features over the basic model:

1. You can enter your KWH rate and it will tell you how much - in dollars
and cents - the reading cost, and
2. Has a battery backup so it doesn't reset when the power goes off.

If you don't know how to multiply, or do not have access to a calculator, #1
may be necessary. If you want to accumulate readings over a power outage
situation, #2 might be a help.

Neither "enhancement" seems useful for the needs you have.

I guess I'm missing something here. They give you some data, but
other than curiosity, what usefullness does that data serve. Plug a
refrig into one and learn it uses x kw and costs x $ per month. But
there ain't a darn thing you can do about it except buy a new frig.
Ditto for all the other appliances you have in your home. Yeah, I can
see figuring what loads you can put on a generator, but other than
that, what 'useful' data do they provide?

KC

On Tue, 27 Oct 2009 20:19:23 -0700 (PDT), KC wrote:

:I guess I'm missing something here. They give you some data, but
ther than curiosity, what usefullness does that data serve. Plug a
:refrig into one and learn it uses x kw and costs x $ per month. But
:there ain't a darn thing you can do about it except buy a new frig.
itto for all the other appliances you have in your home. Yeah, I can
:see figuring what loads you can put on a generator, but other than
:that, what 'useful' data do they provide?
:
:KC

Depends how deep your pockets are. Some people don't give a damn about
20 watts. Others do. 20 watts costs me about $20/year when drawn
24/7/365. Personally, I want to know.

Dan


Email: dmusicant at pacbell dot net

In , D. Musicant wrote in part:

Depends how deep your pockets are. Some people don't give a damn about
20 watts. Others do. 20 watts costs me about $20/year when drawn
24/7/365. Personally, I want to know.

20 watts 24/7/365 costs me $26 per year, in the Pennsylvania
portion of the Philadelphia metro area. Chicago and NYC are similar.

Philadelphia regular residential rate has a surcharge for using more
than 500 KWH per month during air conditioning season - so an
eliminatable 20 watt continuous load may cost more like $30 annually.

There is a looming threat for this to increase substantially in 14
months, when a rate regulation affecting me ends. My power company is
advertizing this on radio, advising their customers to get into
conservation.

- Don Klipstein )

Here on Long Island that's $37 per year.

Bernie

"Don Klipstein" wrote in message
...
In , D. Musicant wrote in
part:

Depends how deep your pockets are. Some people don't give a damn about
20 watts. Others do. 20 watts costs me about $20/year when drawn
24/7/365. Personally, I want to know.

20 watts 24/7/365 costs me $26 per year, in the Pennsylvania
portion of the Philadelphia metro area. Chicago and NYC are similar.

Philadelphia regular residential rate has a surcharge for using more
than 500 KWH per month during air conditioning season - so an
eliminatable 20 watt continuous load may cost more like $30 annually.

There is a looming threat for this to increase substantially in 14
months, when a rate regulation affecting me ends. My power company is
advertizing this on radio, advising their customers to get into
conservation.

- Don Klipstein )

zxcvbob wrote:

Anybody familiar with them?

Yes! They are the cat's whiskers.

Is the "EZ" (model P4460) worth an
extra $15 over model P4400?

If you need sizzle with your steak, I suppose so. It appears that
the EZ has a built in calculator so you can plug in your electric cost
& 'predict' annual costs.

Amazon has the basic P4400 for $20.62 [buy something else for $5 & the
shipping is free]. The 4600 is $34. I wouldn't spend the
extra, myself. I like the KISS principle-- If I need to
calculate cost or future usage I'll do the math in my head or on a $2
calculator. . . or maybe even dig out a pencil.

Jim

Jim Elbrecht wrote:
zxcvbob wrote:

Anybody familiar with them?

Yes! They are the cat's whiskers.

Is the "EZ" (model P4460) worth an
extra $15 over model P4400?

If you need sizzle with your steak, I suppose so. It appears that
the EZ has a built in calculator so you can plug in your electric cost
& 'predict' annual costs.

Amazon has the basic P4400 for $20.62 [buy something else for $5 & the
shipping is free]. The 4600 is $34. I wouldn't spend the
extra, myself. I like the KISS principle-- If I need to
calculate cost or future usage I'll do the math in my head or on a $2
calculator. . . or maybe even dig out a pencil.

Jim

Frys periodically has the P4400 on sale for $14.99. If you
use 120vac devices, you should have at least one. I use
them to size battery requirements for UPS.

On Sat, 24 Oct 2009 23:16:31 -0500, zxcvbob
wrote:

Anybody familiar with them? Is the "EZ" (model P4460) worth an
extra $15 over model P4400?

I want to see how much electricity my freezers, TV sets, computers,
etc are *really* using, plus check the frequency stability of my
portable generator and that little inverter than I mounted in my truck.

Thanks,
Bob

It may not work on a freezer. It has built in over current protection
that kills power to the device and a freezer may be too much to
handle. I know I cant get a reading off my fridge because the
compressor start up current is over this limit.

On Oct 25, 9:36*am, homer wrote:
On Sat, 24 Oct 2009 23:16:31 -0500, zxcvbob
wrote:

Anybody familiar with them? *Is the "EZ" (model P4460) worth an
extra $15 over model P4400?

I want to see how much electricity my freezers, TV sets, computers,
etc are *really* using, plus check the frequency stability of my
portable generator and that little inverter than I mounted in my truck.

Thanks,
Bob

It may not work on a freezer. *It has built in over current protection
that kills power to the device and a freezer may be too much to
handle. *I know I cant get a reading off my fridge because the
compressor start up current is over this limit.

I'd definitely get the EZ model. It's worth the small addional cost.
You can enter the cost of electricity per KWh and it then will
directly display how much it costs to run the load per day, week,
month or year. You can just leave it up on the display and watch it
update, glance at it during the day, etc. Much better than just
seeing XX Kwh and having to manually do the translation.

Good news is Costco has them for $27.

Bad news is that about 6 months ago I bought one and it was bad. One
push button did not work at all. Took it back and got another one.
That one, a different button didn't work at all. So, I waited
hoping the crap ones would clear out. Bought one last week and it's
working perfectly, at least so far.....

I've put one on two refrigerators, a 24 year old one and a new one.
It worked on both.

On Oct 25, 11:11*am, wrote:
On Sun, 25 Oct 2009 07:30:37 -0700 (PDT), wrote:
On Oct 25, 9:36*am, homer wrote:
On Sat, 24 Oct 2009 23:16:31 -0500, zxcvbob
wrote:

Anybody familiar with them? *Is the "EZ" (model P4460) worth an
extra $15 over model P4400?

I want to see how much electricity my freezers, TV sets, computers,
etc are *really* using, plus check the frequency stability of my
portable generator and that little inverter than I mounted in my truck.

Thanks,
Bob

It may not work on a freezer. *It has built in over current protection
that kills power to the device and a freezer may be too much to
handle. *I know I cant get a reading off my fridge because the
compressor start up current is over this limit.

I'd definitely get the EZ model. *It's worth the small addional cost.
You can enter the cost of electricity per KWh and it then will
directly display how much it costs to run the load per day, week,
month or year. * *You can just leave it up on the display and watch it
update, glance at it during the day, etc. * Much better than just
seeing XX Kwh and having to manually do the translation.

Good news is Costco has them for $27.

Bad news is that about 6 months ago I bought one and it was bad. * One
push button did not work at all. * Took it back and got another one.
That one, a different button didn't work at all. * *So, I waited
hoping the crap ones would clear out. * Bought one last week and it's
working perfectly, at least so far.....

I've put one on two refrigerators, a 24 year old one and a new one.
It worked on both.

The first eye opener for most people is just how little power a fridge
actually uses. It is certainly not the power hog most people think it
is. (a new one).
My side by side, ice in the door Whirlpool used 120KWH in 61.2 days
(August September) and it was outside in the Florida summer heat in
the pool bar. If it was in the house I would expect a lower number but
the difference might show up in the A/C bill..

Depends on the age of the fridge. I bought my kill-a-watt to build a
case for buying a new one. Our refrigerator dated to the 1960s and
after monitoring for a few weeks with the kill a watt meter, looked
like annual usage would be around 2400 KWH, about four times what the
new ones use. So the meter was a good investment of $20, we save
almost that much every month on electricity with the new fridge. -- H

On Oct 24, 10:16 pm, zxcvbob wrote:
Anybody familiar with them? Is the "EZ" (model P4460) worth an
extra $15 over model P4400?

I want to see how much electricity my freezers, TV sets, computers,
etc are *really* using, plus check the frequency stability of my
portable generator and that little inverter than I mounted in my truck.

Thanks,
Bob

Andy comments:

I'd like to suggest an alternative.

You can get a "clip on" multimeter from harborfreight.com (free
catalog) for about
$10.00 and measure the current consumed by the device by simply
clipping around
one of the wires (usually the black one) going to the device, and it
will work for any
device that works on 60 cycle AC. The current, times 120, is the kva
in watts.
A simple calc yields the cost per hour to run it.

For frequency of your generator, just plug in one of those $5 electric
clocks and
compare the time to that of your watch. The longer the run time, the
better. If the
frequency is lower, the time on the electric clock will be less than
the time on
your watch, by the same proportion.

Neither of these alternatives are as easy as what you have proposed,
but use
instruments that can be used for other things.

Just a suggestion.

Andy in Eureka, Texas

Andy wrote:

-snip-
I'd like to suggest an alternative.

You can get a "clip on" multimeter from harborfreight.com (free
catalog) for about
$10.00 and measure the current consumed by the device by simply
clipping around
one of the wires (usually the black one) going to the device, and it
will work for any
device that works on 60 cycle AC. The current, times 120, is the kva
in watts.
A simple calc yields the cost per hour to run it.

Not exactly the same as a Kil-o-watt meter.. That gives the cost
*for that hour*. There are a lot of variables over the course of a
24hr day. Defrost cycles, number of refrigeration cycles, etc.


For frequency of your generator, just plug in one of those $5 electric
clocks and
compare the time to that of your watch. The longer the run time, the
better. If the
frequency is lower, the time on the electric clock will be less than
the time on
your watch, by the same proportion.

Neither of these alternatives are as easy as what you have proposed,
but use
instruments that can be used for other things.

I can't imagine a household that won't get $25 worth of use from a
Kill-o-watt meter in a few years. It is one of those things that
once you have it, you find more and more occasions to plug it in.

Jim

On Wed, 28 Oct 2009 08:01:34 -0400, Jim Elbrecht
wrote:

There are a lot of variables over the course of a
24hr day. Defrost cycles, number of refrigeration cycles, etc.

BTW, this Sunday has 25 hours (at least in the US where the mess of
Damn Stupid Time intrudes on reality).
--
58 days until the winter solstice celebration

Mark Lloyd
http://notstupid.us

"How could you ask me to believe in God when there's
absolutely no evidence that I can see?" -- Jodie Foster

Mark Lloyd wrote:
On Wed, 28 Oct 2009 08:01:34 -0400, Jim Elbrecht
wrote:

There are a lot of variables over the course of a
24hr day. Defrost cycles, number of refrigeration cycles, etc.

BTW, this Sunday has 25 hours (at least in the US where the mess of
Damn Stupid Time intrudes on reality).

I wouldn't mind if we stayed on DST all year. The worst part of it is
in the fall when we go back to standard time. My internal clock doesn't
like waking up earlier.

On Oct 29, 9:46*am, Tony wrote:
Mark Lloyd wrote:
On Wed, 28 Oct 2009 08:01:34 -0400, Jim Elbrecht
wrote:

There are a lot of variables over the course of a
24hr day. *Defrost cycles, number of refrigeration cycles, etc.

BTW, this Sunday has 25 hours (at least in the US where the mess of
Damn Stupid Time intrudes on reality).

I wouldn't mind if we stayed on DST all year. *The worst part of it is
in the fall when we go back to standard time. *My internal clock doesn't
like waking up earlier.

um, that's the spring. and I hate it too...

nate

On Thu, 29 Oct 2009 09:46:29 -0400, Tony
wrote:

Mark Lloyd wrote:
On Wed, 28 Oct 2009 08:01:34 -0400, Jim Elbrecht
wrote:

There are a lot of variables over the course of a
24hr day. Defrost cycles, number of refrigeration cycles, etc.

BTW, this Sunday has 25 hours (at least in the US where the mess of
Damn Stupid Time intrudes on reality).

I wouldn't mind if we stayed on DST all year.

That would be fine. The problems are when you keep CHANGING it.

Maybe you realize that DST all the time is the same as no DST at all.
Clocks are an hour different, but we'd adapt to that. There'd just be
no changes to keep messing things up.

The worst part of it is
in the fall when we go back to standard time. My internal clock doesn't
like waking up earlier.

I think that's common. The natural thing is waking up later.

I'm working on a web page that calculates countdowns. DST has really
made that a lot more complicated (as one little example, most
locations change the offset from UTC by 1 hour for DST. However, there
is one exception: Lord Howe Island, where it's .5 hour).
--
56 days until the winter solstice celebration

Mark Lloyd
http://notstupid.us

"How could you ask me to believe in God when there's
absolutely no evidence that I can see?" -- Jodie Foster

You can get a "clip on" multimeter from harborfreight.com *(free
catalog) for about
$10.00 and measure the current consumed by the device by simply
clipping around
one of the wires (usually the black one) going to the device, and it
will work for any
device that works on 60 cycle AC. *The current, times 120, is the kva
in watts.


In an AC circuit, Volt x Amps are not exactly the same thing as Watts
due to power factor.

For loads like incandesenct light bulbs and resistance heaters, the
power facotr is very close to one so there is little error but for
reactive loads like motors, there can be a significant difference.

Mark

Andy wrote:
On Oct 24, 10:16 pm, zxcvbob wrote:
Anybody familiar with them? Is the "EZ" (model P4460) worth an
extra $15 over model P4400?

I want to see how much electricity my freezers, TV sets, computers,
etc are *really* using, plus check the frequency stability of my
portable generator and that little inverter than I mounted in my truck.

Thanks,
Bob

Andy comments:

I'd like to suggest an alternative.

You can get a "clip on" multimeter from harborfreight.com (free
catalog) for about
$10.00 and measure the current consumed by the device by simply
clipping around
one of the wires (usually the black one) going to the device, and it
will work for any
device that works on 60 cycle AC. The current, times 120, is the kva
in watts.

You will get the VA, not the watts. They are not the same except for a
pure resistance load like a light bulb. They are not the same because of
"power factor". If you want the cost of using anything with a motor you
need to know the watts.

"Andy" wrote in message
I'd like to suggest an alternative.

You can get a "clip on" multimeter from harborfreight.com (free
catalog) for about
$10.00 and measure the current consumed by the device by simply
clipping around
one of the wires (usually the black one) going to the device, and it
will work for any
device that works on 60 cycle AC. The current, times 120, is the kva
in watts.
A simple calc yields the cost per hour to run it.

The advantage of a Kill a Watt meter is that it records over time. It takes
fluctuating load into consideration, especially important on refrigerators
and freezers that have a varying load over time, from nothing to full power
with compressor and defrost equipment in use. A spot check will not give
the complete story. Also, no splitting of the cord is required.

Your system works well with simple load that are constant when on.

On Sat, 24 Oct 2009 23:16:31 -0500, zxcvbob wrote:

:Anybody familiar with them? Is the "EZ" (model P4460) worth an
:extra $15 over model P4400?
:
:I want to see how much electricity my freezers, TV sets, computers,
:etc are *really* using, plus check the frequency stability of my
ortable generator and that little inverter than I mounted in my truck.
:
:Thanks,
:Bob

Two things:

I.

I bought the P4400 in February of 2008. I left it plugged into a power
strip and plugged my desktop computer's power strip (and etc.) plugged
into the Kill-a-Watt meter, measuring power draw (watts), for an
indefinite time. It stopped working. It came back to life, don't
remember the details, but leaving it off and unplugged for a while, it
started working somehow. Someone said they thought that the meters
aren't designed to be used in this way, so I stopped doing it.

II.

I've found that the P4400 (don't know about the other(s)) doesn't
measure low power draw at all accurately. IOW, if your device is drawing
3-4 watts, say, the P4400 doesn't give you anything like an accurate
reading. I only know this because I have a far more accurate way of
measuring power draw, which I have used for years. The P4400 is a lot
easier to use, but my system is much more accurate and I feel I can
depend on it more. It's a simple thing I put together for next to
nothing:

1. I already had a decent digital multimeter that measures AC amps,
easily converted into watts (amps x 120 volts = watts). It cost me
around $100 in the early 1990's.

2. I bought a couple of banana plugs that will fit in the multimeter's
input jacks and attached them to a length of AC two conductor cord,
around 6 feet long. The other end of this ~6 foot length of cord is
soldered (both leads) to either end of a cut wire in a short extension
cord. IOW, I cut one wire in the middle of that extension cord and
connected the cut ends to the cord, the other end of which has the
banana plugs. Plugging the banana plugs into the multimeter first
(ALWAYS do it this way or you will likely cause a dangerous short !), I
THEN plug the extension cord into a power outlet and then a device into
the female end of the extension cord. The multimeter gives me the
current draw and simple arithmetic gives me the watts. Amps x 120 =
watts.

Using this system I determined that the P4400 is useless for low draw
measurement. I don't remember the cutoff where the P4400 starts being
useful. I assume that this holds true for all of them and that I don't
have a lemon here.

Dan


Email: dmusicant at pacbell dot net

Dan Musicant wrote:
On Sat, 24 Oct 2009 23:16:31 -0500, zxcvbob wrote:

:Anybody familiar with them? Is the "EZ" (model P4460) worth an
:extra $15 over model P4400?
:
:I want to see how much electricity my freezers, TV sets, computers,
:etc are *really* using, plus check the frequency stability of my
ortable generator and that little inverter than I mounted in my truck.
:
:Thanks,
:Bob

Two things:

I.

I bought the P4400 in February of 2008. I left it plugged into a power
strip and plugged my desktop computer's power strip (and etc.) plugged
into the Kill-a-Watt meter, measuring power draw (watts), for an
indefinite time. It stopped working. It came back to life, don't
remember the details, but leaving it off and unplugged for a while, it
started working somehow. Someone said they thought that the meters
aren't designed to be used in this way, so I stopped doing it.

II.

I've found that the P4400 (don't know about the other(s)) doesn't
measure low power draw at all accurately. IOW, if your device is drawing
3-4 watts, say, the P4400 doesn't give you anything like an accurate
reading. I only know this because I have a far more accurate way of
measuring power draw, which I have used for years. The P4400 is a lot
easier to use, but my system is much more accurate and I feel I can
depend on it more. It's a simple thing I put together for next to
nothing:

1. I already had a decent digital multimeter that measures AC amps,
easily converted into watts (amps x 120 volts = watts). It cost me
around $100 in the early 1990's.

2. I bought a couple of banana plugs that will fit in the multimeter's
input jacks and attached them to a length of AC two conductor cord,
around 6 feet long. The other end of this ~6 foot length of cord is
soldered (both leads) to either end of a cut wire in a short extension
cord. IOW, I cut one wire in the middle of that extension cord and
connected the cut ends to the cord, the other end of which has the
banana plugs. Plugging the banana plugs into the multimeter first
(ALWAYS do it this way or you will likely cause a dangerous short !), I
THEN plug the extension cord into a power outlet and then a device into
the female end of the extension cord. The multimeter gives me the
current draw and simple arithmetic gives me the watts. Amps x 120 =
watts.

Using this system I determined that the P4400 is useless for low draw
measurement. I don't remember the cutoff where the P4400 starts being
useful. I assume that this holds true for all of them and that I don't
have a lemon here.

Dan


Email: dmusicant at pacbell dot net

Your "accurate" system measures VA, not Watts. Read up on power factor,
the effect of an out-of-phase relationship between volts and amps.

On Sun, 01 Nov 2009 15:28:15 -0600, cjt
wrote:

an Musicant wrote:
: On Sat, 24 Oct 2009 23:16:31 -0500, zxcvbob wrote:
:
: :Anybody familiar with them? Is the "EZ" (model P4460) worth an
: :extra $15 over model P4400?
: :
: :I want to see how much electricity my freezers, TV sets, computers,
: :etc are *really* using, plus check the frequency stability of my
: ortable generator and that little inverter than I mounted in my truck.
: :
: :Thanks,
: :Bob
:
: Two things:
:
: I.
:
: I bought the P4400 in February of 2008. I left it plugged into a power
: strip and plugged my desktop computer's power strip (and etc.) plugged
: into the Kill-a-Watt meter, measuring power draw (watts), for an
: indefinite time. It stopped working. It came back to life, don't
: remember the details, but leaving it off and unplugged for a while, it
: started working somehow. Someone said they thought that the meters
: aren't designed to be used in this way, so I stopped doing it.
:
: II.
:
: I've found that the P4400 (don't know about the other(s)) doesn't
: measure low power draw at all accurately. IOW, if your device is drawing
: 3-4 watts, say, the P4400 doesn't give you anything like an accurate
: reading. I only know this because I have a far more accurate way of
: measuring power draw, which I have used for years. The P4400 is a lot
: easier to use, but my system is much more accurate and I feel I can
: depend on it more. It's a simple thing I put together for next to
: nothing:
:
: 1. I already had a decent digital multimeter that measures AC amps,
: easily converted into watts (amps x 120 volts = watts). It cost me
: around $100 in the early 1990's.
:
: 2. I bought a couple of banana plugs that will fit in the multimeter's
: input jacks and attached them to a length of AC two conductor cord,
: around 6 feet long. The other end of this ~6 foot length of cord is
: soldered (both leads) to either end of a cut wire in a short extension
: cord. IOW, I cut one wire in the middle of that extension cord and
: connected the cut ends to the cord, the other end of which has the
: banana plugs. Plugging the banana plugs into the multimeter first
: (ALWAYS do it this way or you will likely cause a dangerous short !), I
: THEN plug the extension cord into a power outlet and then a device into
: the female end of the extension cord. The multimeter gives me the
: current draw and simple arithmetic gives me the watts. Amps x 120 =
: watts.
:
: Using this system I determined that the P4400 is useless for low draw
: measurement. I don't remember the cutoff where the P4400 starts being
: useful. I assume that this holds true for all of them and that I don't
: have a lemon here.
:
: Dan
:
:
: Email: dmusicant at pacbell dot net
:
:Your "accurate" system measures VA, not Watts. Read up on power factor,
:the effect of an out-of-phase relationship between volts and amps.

Could you explain further? I'm measuring amps on 120v AC. My
understanding is AC amps x AC volts = Watts. Not so? Why?

Dan

PS What's VA?


Email: dmusicant at pacbell dot net

Dan Musicant wrote:
On Sun, 01 Nov 2009 15:28:15 -0600, cjt
wrote:

an Musicant wrote:
: On Sat, 24 Oct 2009 23:16:31 -0500, zxcvbob wrote:
:
: :Anybody familiar with them? Is the "EZ" (model P4460) worth an
: :extra $15 over model P4400?
: :
: :I want to see how much electricity my freezers, TV sets, computers,
: :etc are *really* using, plus check the frequency stability of my
: ortable generator and that little inverter than I mounted in my truck.
: :
: :Thanks,
: :Bob
:
: Two things:
:
: I.
:
: I bought the P4400 in February of 2008. I left it plugged into a power
: strip and plugged my desktop computer's power strip (and etc.) plugged
: into the Kill-a-Watt meter, measuring power draw (watts), for an
: indefinite time. It stopped working. It came back to life, don't
: remember the details, but leaving it off and unplugged for a while, it
: started working somehow. Someone said they thought that the meters
: aren't designed to be used in this way, so I stopped doing it.
:
: II.
:
: I've found that the P4400 (don't know about the other(s)) doesn't
: measure low power draw at all accurately. IOW, if your device is drawing
: 3-4 watts, say, the P4400 doesn't give you anything like an accurate
: reading. I only know this because I have a far more accurate way of
: measuring power draw, which I have used for years. The P4400 is a lot
: easier to use, but my system is much more accurate and I feel I can
: depend on it more. It's a simple thing I put together for next to
: nothing:
:
: 1. I already had a decent digital multimeter that measures AC amps,
: easily converted into watts (amps x 120 volts = watts). It cost me
: around $100 in the early 1990's.
:
: 2. I bought a couple of banana plugs that will fit in the multimeter's
: input jacks and attached them to a length of AC two conductor cord,
: around 6 feet long. The other end of this ~6 foot length of cord is
: soldered (both leads) to either end of a cut wire in a short extension
: cord. IOW, I cut one wire in the middle of that extension cord and
: connected the cut ends to the cord, the other end of which has the
: banana plugs. Plugging the banana plugs into the multimeter first
: (ALWAYS do it this way or you will likely cause a dangerous short !), I
: THEN plug the extension cord into a power outlet and then a device into
: the female end of the extension cord. The multimeter gives me the
: current draw and simple arithmetic gives me the watts. Amps x 120 =
: watts.
:
: Using this system I determined that the P4400 is useless for low draw
: measurement. I don't remember the cutoff where the P4400 starts being
: useful. I assume that this holds true for all of them and that I don't
: have a lemon here.
:
: Dan
:
:
: Email: dmusicant at pacbell dot net
:
:Your "accurate" system measures VA, not Watts. Read up on power factor,
:the effect of an out-of-phase relationship between volts and amps.

Could you explain further? I'm measuring amps on 120v AC. My
understanding is AC amps x AC volts = Watts. Not so? Why?

Dan

PS What's VA?


Email: dmusicant at pacbell dot net

Amps times volts equal watts when the current and voltage are in
phase (i.e. a purely resistive load). When they are out of phase,
there's an additional "power factor" applied to convert what is
then volt-amps (VA) to watts (W). It all goes back to the true
definition of AC watts, which is an integral (as in calculus) over
time of instantaneous voltage times instantaneous current. If you
actually do the calculus, you should be able to determine power
factor as a function of phase angle. I bet the folks in Wikipedia
(or your favorite source on the Internet, whatever it might be)
have an even clearer explanation. :-)