Panasonic Plasma TV standby power usage - ~90-fold higher than specified

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727 posts

Ultimate Geek

#584912 22-Feb-2012 01:57

Yeah - that's pretty much what I'm doing now with the in-line unit I have, and the result I'm getting is telling me something is up, and the suggestion is that it is the meter.

That brings up the question again of what brand of meter I should be trying to beg/borrow/hire. There's no point in me getting another one that people will just say "You can't believe that - it probably doesn't handle [something-or-other] properly."

(I believe that there are also clamp meters, that place a ring around a conductor and measure current by induction.)

merlinz

41 posts

Geek

#584919 22-Feb-2012 06:56

I did get myself (2nd hand on TM) a calibrated power meter of the type hung on meter boards by the power company - older style with the rotating disc. As I said it's a while ago so I can't be 100% sure but my recollection is that it was actually because I was so frustrated by the nonsense the Elto meter was putting out. Set it up on a little wooden stand as it had to be vertical or it would misbehave too (e.g. disc would drag). Anyway I believe I used it also to check the TV consumption and was still satisfied that the spec was credible. The big meter had to go again when we downsized so I can't repeat the test.

merlinz

41 posts

Geek

#584930 22-Feb-2012 07:50

With a new Panasonic plasma (GT30Z series) - nominal 0.4W standby - my Elto reports 21W. The true RMS current measurement on DMM shows .22A for a while after plug-in and then a relay clicks off and the meter then shows zero - presumbably below a min threshold on the 10A range. Unfortunately the mA range is only 200 max so I'll probably blow the fuse if I use that. Need someone better equipped...

TechSol

299 posts

Ultimate Geek

Technical Solutions Aust

#584956 22-Feb-2012 09:08

xarqi: The meter I have was indicating 100% power factor during my tests. Doesn't that mean the load was effectively resistive?

Right here is why I wouldn't trust that meter.... there is no way a TV set (on or on standby) would have a power factor of 1

hashbrown

463 posts

Ultimate Geek

#584979 22-Feb-2012 09:38

This may sound crude, but have you tried checking the temperature.

27W even distributed across a 50inch plasma should cause it to heat up. If you leave it on standby overnight and it feels cold to the touch in the morning, it's your meter that is faulty.

xarqi

727 posts

Ultimate Geek

#585027 22-Feb-2012 10:35

merlinz: With a new Panasonic plasma (GT30Z series) - nominal 0.4W standby - my Elto reports 21W. The true RMS current measurement on DMM shows .22A for a while after plug-in and then a relay clicks off and the meter then shows zero - presumbably below a min threshold on the 10A range. Unfortunately the mA range is only 200 max so I'll probably blow the fuse if I use that. Need someone better equipped...

I see something a bit similar, with the power consumption reported by my ELTO being about 36 W, dropping to 27 W after the relay trips.

Evilg:
xarqi: The meter I have was indicating 100% power factor during my tests. Doesn't that mean the load was effectively resistive?

Right here is why I wouldn't trust that meter.... there is no way a TV set (on or on standby) would have a power factor of 1

Is that based on theory or measurement with a reliable meter?

hashbrown: This may sound crude, but have you tried checking the temperature.

27W even distributed across a 50inch plasma should cause it to heat up. If you leave it on standby overnight and it feels cold to the touch in the morning, it's your meter that is faulty.

Yeah - good idea, but I think the only way it would be conclusive is if the TV were noticeably warm. In fact, it does seem by touch to be about ambient, but without an IR thermometer I couldn't say for sure. The mass is pretty large, and the ventilation good as it has to dissipate much more than that when operating, so I can't completely discount the possibility that it's running at 27 W. I'm trying to imagine how hot I'd expect it to be with 3 or 4 CFL lights running in there continuously, and yeah, my sense is that it would be warmer than I'm finding it to be.

So, another finger pointing at the meter.

No reply from Panasonic yet.

dolsen

1476 posts

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#585050 22-Feb-2012 11:11

gzt: There was a discussion here a while ago where a guy got a 69W standby figure for a microwave using the Elto. That was not rechecked with anything else but it seems unlikely.

That was me (thread is here)

From my findings, I believe the two button cell elto power meter is a load of junk and not to be trusted.

No, I still haven't rechecked using my fluke meter due to not being able to find a low priced fuse for it (FLU-11 / DMM-11A), but, I do beleive that that the issue is the power meter that can not correctly measure power...

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xarqi

727 posts

Ultimate Geek

#585058 22-Feb-2012 11:22

dolsen:
gzt: There was a discussion here a while ago where a guy got a 69W standby figure for a microwave using the Elto. That was not rechecked with anything else but it seems unlikely.

That was me (thread is here)

From my findings, I believe the two button cell elto power meter is a load of junk and not to be trusted.

No, I still haven't rechecked using my fluke meter due to not being able to find a low priced fuse for it (FLU-11 / DMM-11A), but, I do beleive that that the issue is the power meter that can not correctly measure power...

Hmmm - I think I read that thread at the time and had in mind that there was a bad ELTO model, but when I was in the Warehouse and saw a meter marked down to cheap I thought I'd take a punt.

I wonder if I still have my receipt. Armed with that and a copy of this thread maybe I could get my $14 back! ;)

So, can anyone recommend a reliable similar product, keeping in mind that it will need to be cheap or it is unlikely to pay for itself by identifying areas for power saving. Let's say under $50.

TechSol

299 posts

Ultimate Geek

Technical Solutions Aust

#585125 22-Feb-2012 12:29

xarqi:

Evilg:
xarqi: The meter I have was indicating 100% power factor during my tests. Doesn't that mean the load was effectively resistive?

Right here is why I wouldn't trust that meter.... there is no way a TV set (on or on standby) would have a power factor of 1

Is that based on theory or measurement with a reliable meter?

Based off many years of performing energy audits and testing equipment, using extremely expensive measuring and logging gear.

typically if you get above .96 power factor on a non-resistive load, you are doing really well.... but that is an aside.

clevedon

1059 posts

Uber Geek

#585129 22-Feb-2012 12:37

xarqi: 27 W for a TV seems unlikely too, and that is the cause of my concern. Something is amiss somewhere: the TV, the specification, or the measurement. My trilemma, I guess that's the word, is which.

At the moment, my money is on the specification.

My money is on the meter.

rumpty

66 posts

Master Geek

#585701 23-Feb-2012 13:42

Where do you live? I have a proper wattmeter here, off an old mains switchboard, that you could borrow. You can watch the disc go round for a few minutes and get a good idea of the consumption.

xarqi

727 posts

Ultimate Geek

#585890 23-Feb-2012 18:40

Thanks for the offer, Rumpty, but I think I'm just going to leave it for now.

I had a reply from Panasonic who assured me that it really was 0.4W, cross my heart, etc. and given the comments here and the probabilities of whose gear is shonky (Panasonic vs ELTO), I'll believe them.

If it was just to lay to rest the issue of the TV I may have taken you up on your kind offer, but that only came up as part of a bigger concern over an overall increase in my power consumption. If I'm going to get to the bottom of that, I think I'm going to need to get my own reliable meter and to take quite a bit of time over it, so I wouldn't want to impose on you.

The alternative of course is just for me to do what I've always done:read the labels and believe them, and turn off the energy hogs that I don't really need.

Jaxson

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#585897 23-Feb-2012 18:48

It's summer man, how bad are your power increases?
Do you have air con on for instance?

xarqi

727 posts

Ultimate Geek

#585911 23-Feb-2012 19:03

Jaxson: It's summer man, how bad are your power increases?
Do you have air con on for instance?

Well,historically, I was getting by on maybe 10-14 kWh/day, summer or winter as I don't use electrical heating, but I'm up to about 18. I added a dehumidifier a while back, and on the basis of my now suspect ELTO meter figured it to be good for about 2 kWh/day. I've since added the 50V20 mentioned (which should actually use less power than the 29" CRT it replaced), and an Onkyo 609 (probably under 1 kWh/day). Most recently, I've put in yet another dehumidifier (I live in a rain forest here), but that won't be being reflected in my bills yet.

All up, that's nearly a 50% jump over the last year, although my actual usage is probably quite low by most people's standards.
I guess the price of supply has gone up too, and maybe that's caused an increase in the bill size that finally impinged on my consciousness and made me wonder where all those joules are going.

Jaxson

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#585913 23-Feb-2012 19:07

2x dehumidifiers is probably not a good start there.

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