I'm finally getting around to thinking about replacing a plasma TV (not
full HD, only SD tuner) if it is too power hungry.

To do that I need to estimate the power drain over 24 hours (or even a
week) and guestimate how much it is costing per year in electricity. A
cost of around £100 per year (say) would be a strong case for a modern LCD
screen. However as the whole house bill is around £1,000 a year this may
be unlikely.

Amazon seems to have some meters around the £10-£20 mark.

https://www.amazon.co.uk/Power-Energ...lectricity/dp/
B00E4H0L40

or

https://www.amazon.co.uk/Energenie-429-856UK-Power-Meter/dp/B003ELLGDC

so will these be reasonably accurate?

Any recommendations?

I can reuse to measure various other pieces of kit, mainly computers.

Cheers




Dave R


--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On 26/04/18 12:54, David wrote:
I'm finally getting around to thinking about replacing a plasma TV (not
full HD, only SD tuner) if it is too power hungry.

To do that I need to estimate the power drain over 24 hours (or even a
week) and guestimate how much it is costing per year in electricity. A
cost of around £100 per year (say) would be a strong case for a modern LCD
screen. However as the whole house bill is around £1,000 a year this may
be unlikely.

Amazon seems to have some meters around the £10-£20 mark.

https://www.amazon.co.uk/Power-Energ...lectricity/dp/
B00E4H0L40

or

https://www.amazon.co.uk/Energenie-429-856UK-Power-Meter/dp/B003ELLGDC

so will these be reasonably accurate?

Any recommendations?

I can reuse to measure various other pieces of kit, mainly computers.

Cheers



trouble wih almost all 'power meters' is that they dont measure RMS
power, they tend to measure VA or some approximation to RMS that falls
down badly when faced with a switched mode power supply

Unless you know how they are measuring the power, be careful.


Dave R




--
"If you dont read the news paper, you are un-informed. If you read the
news paper, you are mis-informed."

Mark Twain

"The Natural Philosopher" wrote in message
news
trouble wih almost all 'power meters' is that they dont measure RMS power,
they tend to measure VA or some approximation to RMS that falls down badly
when faced with a switched mode power supply

Unless you know how they are measuring the power, be careful.

The one I have (somewhere!) can be switched between power in W and power in
VA, and gives the same result for a lightbulb (being resistive) but
different results for anything with a switched mode power supply. That was a
bog-standard meter from Maplin (RIP). It also had a setting that calculated
total energy used (ie power integrated over time) in kWhr.

On Thursday, 26 April 2018 12:58:10 UTC+1, The Natural Philosopher wrote:
On 26/04/18 12:54, David wrote:
I'm finally getting around to thinking about replacing a plasma TV (not
full HD, only SD tuner) if it is too power hungry.

To do that I need to estimate the power drain over 24 hours (or even a
week) and guestimate how much it is costing per year in electricity. A
cost of around £100 per year (say) would be a strong case for a modern LCD
screen. However as the whole house bill is around £1,000 a year this may
be unlikely.

Amazon seems to have some meters around the £10-£20 mark.

https://www.amazon.co.uk/Power-Energ...lectricity/dp/
B00E4H0L40

or

https://www.amazon.co.uk/Energenie-429-856UK-Power-Meter/dp/B003ELLGDC

so will these be reasonably accurate?

Any recommendations?

I can reuse to measure various other pieces of kit, mainly computers.

Cheers



trouble wih almost all 'power meters' is that they dont measure RMS
power, they tend to measure VA or some approximation to RMS that falls
down badly when faced with a switched mode power supply

Unless you know how they are measuring the power, be careful.

Does that realy matter that much unless you want better than 5% accuracy and even them you might not know how they measure your power usage does your energy supplier use RMS or average how much to they account for the phase shift caused by SMPS in computers and TVs and most devices now.
I'm not sure whether or not it matters whether it's RMS or average at this scale.

I have maplin versions at home and at work, they have always been OK for such things and pretty much given me the info I needed.

whisky-dave wrote:

I have maplin versions at home and at work, they have always been OK
for such things and pretty much given me the info I needed.

I have a Maplin one, I don't think it claims to measure true RMS, but it
does allow toggling between W and VA, it's measuring my PC's consumption
now at 35W and 58VA.

n.b. that isn't on direct mains, it's between the PC and a UPS which is
running in buck mode at the moment, so not likely the sineyist of sine
waves.

On Thursday, 26 April 2018 14:13:56 UTC+1, Andy Burns wrote:
whisky-dave wrote:

I have maplin versions at home and at work, they have always been OK
for such things and pretty much given me the info I needed.

I have a Maplin one, I don't think it claims to measure true RMS, but it
does allow toggling between W and VA, it's measuring my PC's consumption
now at 35W and 58VA.

So how much would you say your electric company charges you to have the PC on for say 10 hours is they charge 20p per KWh ?

As I tried to imply the accuracy isnt that important and I assume whether yuo measure true RMS, RMS, average, peak, or pk-pk a TV that measures 50W or 50VA will cost you less to run than a TV measuring 80W or 80VA.


n.b. that isn't on direct mains, it's between the PC and a UPS which is
running in buck mode at the moment, so not likely the sineyist of sine
waves.

but you can elimante these problems by using teh same test equipment and variables.

whisky-dave wrote:

Andy Burns wrote:

measuring my PC's consumption now at 35W and 58VA.

So how much would you say your electric company charges you to have
the PC on for say 10 hours is they charge 20p per KWh ?
Domestic electricity meters all measure Watts rather than VA, so 7p at
that price.

between the PC and a UPS which is running in buck mode at the
moment, so not likely the sineyist of sine waves.

but you can elimante these problems by using teh same test equipment and variables.

I'd have to reboot the PC to plug it into the mains, measure and then
reboot again to put it back onto the UPS ... not convenient at the moment.

In article ,
whisky-dave scribeth thus
On Thursday, 26 April 2018 14:13:56 UTC+1, Andy Burns wrote:
whisky-dave wrote:

I have maplin versions at home and at work, they have always been OK
for such things and pretty much given me the info I needed.

I have a Maplin one, I don't think it claims to measure true RMS, but it
does allow toggling between W and VA, it's measuring my PC's consumption
now at 35W and 58VA.

So how much would you say your electric company charges you to have the PC on
for say 10 hours is they charge 20p per KWh ?

Feck them at that price, thats what I'd say;!...


--
Tony Sayer

On Thu, 26 Apr 2018 14:13:53 +0100, Andy Burns wrote:

whisky-dave wrote:

I have maplin versions at home and at work, they have always been OK
for such things and pretty much given me the info I needed.

I have a Maplin one, I don't think it claims to measure true RMS, but it
does allow toggling between W and VA, it's measuring my PC's consumption
now at 35W and 58VA.

n.b. that isn't on direct mains, it's between the PC and a UPS which is
running in buck mode at the moment, so not likely the sineyist of sine
waves.

That's enough ******** between Martin Brown's claim that recent plug in
energy monitors are inaccurate on small sub 10W loads and only read to
the nearest watt +/- 10W (true of the very first sub ten quid Machinemart/
Netto/Aldi units from over a decade ago), and this business you've just
mentioned of a line interactive UPS somehow magically distorting the
mains voltage waveform just by selecting a lower voltage tap on its mains
transformer to restore the mains voltage back to 240v[1], so I'd like to
dispel these myths.

As mentioned, it's been a good decade since useless plug in energy
monitors were last miss-sold to the general public. Any current plug in
energy monitors sold during the past 6 or 7 years (maybe longer) have
proven to be remarkably accurate to within +/-3% of VA and Wattage
readings (and, therefore of necessity, to within +/-1.5% of voltage and
current readings).

They all display readings to a tenth of a watt resolution (although one
model I have only does this for readings above 1W) and display to a
maximum of 3120W or so (I noticed a 5 quid model on Amazon claiming it
would only read to a maximum of 2998W before cutting out).

These "Plug in Energy Monitors"(aka fancy digital watt meters) have
improved beyond all recognition since such devices first appeared some 15
years back. IOW, they're quite a useful measuring tool to have for
checking the consumption of IT kit such as modem/routers, ethernet
switches and PCs (as well as the standby power of TV sets and USB
chargers).

As for your assumption, Andy, regarding the power feed to your PC not
being the "sineyist of sine waves", well you're right (up to a point) but
not on account of the line interactive UPS bucking the voltage with its
transformer. The lack of sine wave purity originates with the mains
supply itself which can best be described as a sine wave that's had its
peaks neatly sliced off with the flat tops showing a slight down slope on
the positive peaks and vice-versa for the negative peaks.

If you can observe the mains waveform on a proper oscilloscope (or audio
captured using an audio recording app that will let you zoom in on the
recorded waveform (CoolEdit Pro or Audacity) from the output of a 5 to
15vac output wallwart transformer attenuated with a resistor network down
to half a volt rms or less to avoid overloading the line input of your
sound card), you will be able to observe this for yourself.

If you remove the mains input from the UPS whilst observing/recording
the waveform on the protected side as I've just described, you will
either see a horribly shaped squareish wave or else see a perfect sine
wave replace the slightly distorted mains voltage waveform, depending on
the quality of your UPS.

If for example, you have an APC SmartUPS, expect the quality of the
"mains waveform" to improve (I believe all APC models of "SmartUPS"
provide sine wave outputs). :-)

[1] Or 230v if you believe that our UK mains supply has actually been
adjusted to conform to the notional 230v rating of electrical goods sold/
manufactured throughout the whole of the EC rather than left exactly as
it always has been except for the change in the voltage tolerances
mandated by new regulations catering for the notional 230v ratings of new
appliances.

--
Johnny B Good

Johnny B Good wrote:

As for your assumption, Andy, regarding the power feed to your PC not
being the "sineyist of sine waves", well you're right (up to a point)

The main reason I mentioned that the kill-a-watt was monitoring between
UPS and PC was that I was quite surprised the power factor was under 60
and thought someone might query it being that low. The PC has a 550W
PSU and was more or less idling at the time, maybe not ideal for
efficiency or power factor.

Might try CPC then, in the absence of Maplin any more, or look at reviews on
Amazon.
Brian

--
----- -
This newsgroup posting comes to you directly from...
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Blind user, so no pictures please!
"whisky-dave" wrote in message
...
On Thursday, 26 April 2018 12:58:10 UTC+1, The Natural Philosopher wrote:
On 26/04/18 12:54, David wrote:
I'm finally getting around to thinking about replacing a plasma TV (not
full HD, only SD tuner) if it is too power hungry.

To do that I need to estimate the power drain over 24 hours (or even a
week) and guestimate how much it is costing per year in electricity. A
cost of around £100 per year (say) would be a strong case for a modern
LCD
screen. However as the whole house bill is around £1,000 a year this may
be unlikely.

Amazon seems to have some meters around the £10-£20 mark.

https://www.amazon.co.uk/Power-Energ...lectricity/dp/
B00E4H0L40

or

https://www.amazon.co.uk/Energenie-429-856UK-Power-Meter/dp/B003ELLGDC

so will these be reasonably accurate?

Any recommendations?

I can reuse to measure various other pieces of kit, mainly computers.

Cheers



trouble wih almost all 'power meters' is that they dont measure RMS
power, they tend to measure VA or some approximation to RMS that falls
down badly when faced with a switched mode power supply

Unless you know how they are measuring the power, be careful.

Does that realy matter that much unless you want better than 5% accuracy and
even them you might not know how they measure your power usage does your
energy supplier use RMS or average how much to they account for the phase
shift caused by SMPS in computers and TVs and most devices now.
I'm not sure whether or not it matters whether it's RMS or average at this
scale.

I have maplin versions at home and at work, they have always been OK for
such things and pretty much given me the info I needed.

Yes they used to be wrong on old telies that only rectified on one mains
half cycle of course too.

Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"The Natural Philosopher" wrote in message
news
On 26/04/18 12:54, David wrote:
I'm finally getting around to thinking about replacing a plasma TV (not
full HD, only SD tuner) if it is too power hungry.

To do that I need to estimate the power drain over 24 hours (or even a
week) and guestimate how much it is costing per year in electricity. A
cost of around £100 per year (say) would be a strong case for a modern
LCD
screen. However as the whole house bill is around £1,000 a year this may
be unlikely.

Amazon seems to have some meters around the £10-£20 mark.

https://www.amazon.co.uk/Power-Energ...lectricity/dp/
B00E4H0L40

or

https://www.amazon.co.uk/Energenie-429-856UK-Power-Meter/dp/B003ELLGDC

so will these be reasonably accurate?

Any recommendations?

I can reuse to measure various other pieces of kit, mainly computers.

Cheers



trouble wih almost all 'power meters' is that they dont measure RMS power,
they tend to measure VA or some approximation to RMS that falls down badly
when faced with a switched mode power supply

Unless you know how they are measuring the power, be careful.


Dave R




--
"If you don't read the news paper, you are un-informed. If you read the
news paper, you are mis-informed."

Mark Twain

In article ,
David wrote:
I'm finally getting around to thinking about replacing a plasma TV (not
full HD, only SD tuner) if it is too power hungry.

To do that I need to estimate the power drain over 24 hours (or even a
week) and guestimate how much it is costing per year in electricity. A
cost of around £100 per year (say) would be a strong case for a modern LCD
screen. However as the whole house bill is around £1,000 a year this may
be unlikely.

Amazon seems to have some meters around the £10-£20 mark.


Every appliance like this has the power consumption marked on it somewhere
visible.

If you Google, the average power consumption for a plasma is 140 watts.
Average for a modern LCD 90 watts. Both will depend on screen size.

Unless you're TV is on 24/7, I doubt you'll notice the difference in
running costs.

Also, a modern smart TV which is online all the time - even in standby -
may actually use more electricity in standby than an older set.

--
*I used to be a banker, but then I lost interest.*

Dave Plowman London SW
To e-mail, change noise into sound.

On 26/04/2018 12:54, David wrote:
I'm finally getting around to thinking about replacing a plasma TV (not
full HD, only SD tuner) if it is too power hungry.

To do that I need to estimate the power drain over 24 hours (or even a
week) and guestimate how much it is costing per year in electricity. A
cost of around £100 per year (say) would be a strong case for a modern LCD
screen. However as the whole house bill is around £1,000 a year this may
be unlikely.

You may be able to just look up the manual online and see what it says
are the standby (hibernate) and active power consumptions.

If it is an older model then it may well default to powering the digital
tuner continuously so it is worth probing the menus carefully and
disabling that feature. My LCD TV went down from 20W to 1W.

Amazon seems to have some meters around the £10-£20 mark.

https://www.amazon.co.uk/Power-Energ...lectricity/dp/
B00E4H0L40

or

https://www.amazon.co.uk/Energenie-429-856UK-Power-Meter/dp/B003ELLGDC

so will these be reasonably accurate?

Good enough to show you one or two significant figures. They are a bit
flaky on low power devices and switch mode PSUs but better than nothing.

Even so you will find some devices that consume unreasonable amounts of
power when they are supposed to be "off". My PC sound system consumes as
much when switched off as it does when on. The on/off switch merely
disconnects the inputs to the power amplifier and the on LED!

Offending items are now powered from smart sockets that switch
everything off when the PC is either in standby or off.

Worth taking a quick look in Maplin to see if they have any at 30% off.

Any recommendations?

I can reuse to measure various other pieces of kit, mainly computers.

It is probably worthwhile having a whole house monitor with realtime
display if you want to shave ~10% off your electricity bill. Reducing
your 24/7 base load to under 100W will help save money.

I have the Owl (other brands available some free from your electricity
company if you chose the right supplier and tariff).

https://www.amazon.co.uk/CM160-Elect...dp/B004BDNR84/

If the TV is really bad it will easily show up on that when you switch
if on. Resolution is to nearest W but accuracy is more like +/- 10W or
5% (whichever is larger). I installed one in the Village Hall to stop
people from leaving heaters on when they leave.

--
Regards,
Martin Brown

Martin Brown wrote:

Reducing your 24/7 base load to under 100W will [...]

.... be bloody difficult, the lowest I generally see mine overnight is
140W as measured by the smart meter itself, it probably dips to 120 when
I'm actually in bed and all lights are off.

On 26/04/2018 14:18, Andy Burns wrote:
Martin Brown wrote:

Reducing your 24/7 base load to under 100W will [...]

... be bloody difficult, the lowest I generally see mine overnight is
140W as measured by the smart meter itself, it probably dips to 120 when
I'm actually in bed and all lights are off.

It is about what mine is. Router, alarm, emergency lights, cooker and a
host of gadgets in standby/sleep mode. I could get lower if I found a
router that would go to sleep when there was no internet/wifi traffic.

It is worth poking around to see what else is drawing power.

--
Regards,
Martin Brown

On Thursday, 26 April 2018 15:02:38 UTC+1, Martin Brown wrote:
On 26/04/2018 14:18, Andy Burns wrote:
Martin Brown wrote:

Reducing your 24/7 base load to under 100W will [...]

... be bloody difficult, the lowest I generally see mine overnight is
140W as measured by the smart meter itself, it probably dips to 120 when
I'm actually in bed and all lights are off.

It is about what mine is. Router, alarm, emergency lights, cooker and a
host of gadgets in standby/sleep mode. I could get lower if I found a
router that would go to sleep when there was no internet/wifi traffic.

It is worth poking around to see what else is drawing power.

I'd say check anything with an older none SMPS plugin PSU

--
Regards,
Martin Brown

whisky-dave wrote:

I'd say check anything with an older none SMPS plugin PSU
AFAIK, that's just the DAB radio which is 2A@9V and runs at about 45°C
day and night (11W on, 9W standby)

Martin Brown wrote:

Andy Burns wrote:

Martin Brown wrote:

Reducing your 24/7 base load to under 100W will [...]

... be bloody difficult

It is worth poking around to see what else is drawing power.

UPS (probably the largest constant draw, it's warm)
fridge-freezer (periodic rather than 24x7)
toothbrush and clippers charging in bathroom cabinet
oven and microwave flashing "12:00"
router/firewall/access point
DECT basestation + 2 phones in charging cradles
alarm
3xPIRs for outdoor lights
loft amplifier
2x TVs on standby
HTPC on standby
3x USB chargers on standby
DAB radio (non-SMPSU hot even when on standby)
power tool charger
C/H programmer
UFH programmer
3x non-maintained emergency lights
tablet and powered bluetooth speakers used as internet radio

If I leave a PC or laptop running overnight, can't get below 150W

On 26/04/2018 15:24, Andy Burns wrote:
Martin Brown wrote:

Andy Burns wrote:

Martin Brown wrote:

Reducing your 24/7 base load to under 100W will [...]

... be bloody difficult

It is worth poking around to see what else is drawing power.

UPS (probably the largest constant draw, it's warm)
fridge-freezer (periodic rather than 24x7)
toothbrush and clippers charging in bathroom cabinet
oven and microwave flashing "12:00"
router/firewall/access point
DECT basestation + 2 phones in charging cradles
alarm
3xPIRs for outdoor lights
loft amplifier
2x TVs on standby
HTPC on standby
3x USB chargers on standby
DAB radio (non-SMPSU hot even when on standby)
power tool charger
C/H programmer
UFH programmer
3x non-maintained emergency lights
tablet and powered bluetooth speakers used as internet radio

Chances are just a couple of those are responsible for much of it. Older
TVs seem particularly bad about standby. Modern stuff is mostly 1W.

I bet the DAB radio is a power wasting hog on or off.

If I leave a PC or laptop running overnight, can't get below 150W

A PC running and all bets are off. Mine is quite frugal when idle.

--
Regards,
Martin Brown

On Thu, 26 Apr 2018 14:18:47 +0100, Andy Burns wrote:

Reducing your 24/7 base load to under 100W will [...]

.... be bloody difficult, the lowest I generally see mine overnight is
140W as measured by the smart meter itself, it probably dips to 120 when
I'm actually in bed and all lights are off.

Ditto, night time base load minimum is nearer 400 W here.

--
Cheers
Dave.

On 26/04/2018 16:46, Dave Liquorice wrote:
On Thu, 26 Apr 2018 14:18:47 +0100, Andy Burns wrote:

Reducing your 24/7 base load to under 100W will [...]

.... be bloody difficult, the lowest I generally see mine overnight is
140W as measured by the smart meter itself, it probably dips to 120 when
I'm actually in bed and all lights are off.

Ditto, night time base load minimum is nearer 400 W here.

Are you bitcoin mining or something?

--
Regards,
Martin Brown

On 26/04/2018 16:50, Martin Brown wrote:
On 26/04/2018 16:46, Dave Liquorice wrote:
On Thu, 26 Apr 2018 14:18:47 +0100, Andy Burns wrote:

Reducing your 24/7 base load to under 100W will [...]

.... be bloody difficult, the lowest I generally see mine overnight is
140W as measured by the smart meter itself, it probably dips to 120 when
I'm actually in bed and all lights are off.

Ditto, night time base load minimum is nearer 400 W here.

Are you bitcoin mining or something?


Probably similar to me..

three NAS boxes
router
TV recorder
trickle fan in bathroom
several chargers
alarm
fridge
freezer
PIRs
lamp on drive
CCTV recorder and cameras
Aquarium
an echo or two

On Thu, 26 Apr 2018 16:50:01 +0100, Martin Brown wrote:

Ditto, night time base load minimum is nearer 400 W here.

Are you bitcoin mining or something?

400 W might just keep one GPU card mining. B-)

Lets see:
UPS, HP Micro Server, 16 Port unmanaged Giga bit switch, 8 port
managed PoE Gigabit switch, Load balancing router, ADSL modem,
VOIP/POTS/DECT base, 3 handset chargers, 2 AP's, weather station,
blitzortung (PoE), webcam (PoE), CH/HW system (Two programmers, two
Wireless Stat Rx, solar controller, stove controller (two, Raspberry
Pi Zero based one in development), half a dozen mains interlinked
smokes(*), two emergency lights(*), dozen or more wall warts plugged
in powered up but attached kit off or standby (mostly SMPSU's),
couple of lights, freezer, fridge/freezer, aquarium, TV and BD in
standby, microwave with flashing colon, E7 immersion controller, Pi
running XMBC (screws up the CEC if you turn it off),

(*) I suspect the smokes and emergency lights account for the bext
part of 100 W of that 400 Wminimum base load.

--
Cheers
Dave.