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

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xarqi

709 posts

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Reply # 585916 23-Feb-2012 19:14
Jaxson: 2x dehumidifiers is probably not a good start there. Agreed. I just have to weigh the costs against the benefits. It's a struggle to keep the RH below about 65% even with them running. It'll go over 75% with them off.

merlinz

36 posts

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Reply # 585918 23-Feb-2012 19:27
This review of the 3D model of the same vintage (VT20) claims to have measured actual consumption - reported as 1W but they are rounding power to nearest integer so I think that just means something between 0 and 1W. Their reviews are unusually thorough. I see no reason why standby current would be different between 3D and 2D models. Not wanting to stir up another hornet's nest, but I did hook my (fairly cheap, ostensibly true RMS) DMM up to my GT30Z and it showed 99mA = 23W. But I simply don't believe it, I think both it and the Elto are being fooled by the (presumably) inductive load of a relay and have no ability to deal with the true power factor at this level. I would actually trust Panasonic far more.

xarqi

709 posts

Ultimate Geek

Reply # 585925 23-Feb-2012 19:42
merlinz: This review of the 3D model of the same vintage (VT20) claims to have measured actual consumption - reported as 1W but they are rounding power to nearest integer so I think that just means something between 0 and 1W. Their reviews are unusually thorough. I see no reason why standby current would be different between 3D and 2D models. Yup - I'm going to file it as an anomaly, but not worth pursuing. Thanks for your input. Not wanting to stir up another hornet's nest, but I did hook my (fairly cheap, ostensibly true RMS) DMM up to my GT30Z and it showed 99mA = 23W. But I simply don't believe it, I think both it and the Elto are being fooled by the (presumably) inductive load of a relay and have no ability to deal with the true power factor at this level. I would actually trust Panasonic far more. Well, you know what they say: "A man with one watch knows what time it is, but a man with two is never sure." There is a doubt, but I'm happy to give the benefit of that to Panasonic. If other GZers had said "Yeah - that's happening with me too using my super-duper, gold standard, positron powered, Higg's boson filtered watt-hour meter", then maybe there'd be a case to answer.

Skolink

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Reply # 594016 12-Mar-2012 11:47
merlinz: Not wanting to stir up another hornet's nest, but I did hook my (fairly cheap, ostensibly true RMS) DMM up to my GT30Z and it showed 99mA = 23W. But I simply don't believe it, I think both it and the Elto are being fooled by the (presumably) inductive load of a relay and have no ability to deal with the true power factor at this level. It's probably not inductive load that's the problem, but 'non-linear' loads that do not draw sinusoidal current (whether in phase or out of phase with the voltage). A rectifier will typically draw a pulse or spike of current only at the peak of the voltage waveform, worse (sharper spike) when lightly loaded (say when a device is in standby). A cheap meter might measure the peak and assume it represented the level of sinusoidal current draw. My $20 plug-in meter does display power factor, so I would trust it on an AC motor, but I'm not so trusting when it comes to electronics or small loads.

merlinz

36 posts

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Reply # 594160 12-Mar-2012 14:29
Skolink: merlinz: Not wanting to stir up another hornet's nest, but I did hook my (fairly cheap, ostensibly true RMS) DMM up to my GT30Z and it showed 99mA = 23W. But I simply don't believe it, I think both it and the Elto are being fooled by the (presumably) inductive load of a relay and have no ability to deal with the true power factor at this level. It's probably not inductive load that's the problem, but 'non-linear' loads that do not draw sinusoidal current (whether in phase or out of phase with the voltage). A rectifier will typically draw a pulse or spike of current only at the peak of the voltage waveform, worse (sharper spike) when lightly loaded (say when a device is in standby). A cheap meter might measure the peak and assume it represented the level of sinusoidal current draw. My $20 plug-in meter does display power factor, so I would trust it on an AC motor, but I'm not so trusting when it comes to electronics or small loads. I confess I realised straight after posting that was rather shallow thinking about the relay, and I was half expecting to be corrected. Good explanation, thanks.

Skolink

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Reply # 594351 12-Mar-2012 21:58
merlinz: Skolink: merlinz: Not wanting to stir up another hornet's nest, but I did hook my (fairly cheap, ostensibly true RMS) DMM up to my GT30Z and it showed 99mA = 23W. But I simply don't believe it, I think both it and the Elto are being fooled by the (presumably) inductive load of a relay and have no ability to deal with the true power factor at this level. It's probably not inductive load that's the problem, but 'non-linear' loads that do not draw sinusoidal current (whether in phase or out of phase with the voltage). A rectifier will typically draw a pulse or spike of current only at the peak of the voltage waveform, worse (sharper spike) when lightly loaded (say when a device is in standby). A cheap meter might measure the peak and assume it represented the level of sinusoidal current draw. My $20 plug-in meter does display power factor, so I would trust it on an AC motor, but I'm not so trusting when it comes to electronics or small loads. I confess I realised straight after posting that was rather shallow thinking about the relay, and I was half expecting to be corrected. Good explanation, thanks. As an aside, some relays do draw significant current (just to energize the coil). I helped someone troubleshoot excessive current draw on a vehicle while it was off. Turns out someone reconnected a relay round the wrong way, so it was always on drawing current, and the 'control' line just passed straight through the contacts.

stuzzo

512 posts

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Reply # 648942 1-Jul-2012 10:59
Sorry to bring up an old thread but came across it when I noticed the same phenomenon. I think the reason the OP measured high standby power was that when powered down the Panasonic TVs seem to turn off the screen but stay in a high power mode for about 5 mins or so and then power down to their stated standby level. Noticed this on a number of new Panasonics. Not sure of the reason. Housekeeping, checking updates perhaps?

xarqi

709 posts

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Reply # 648984 1-Jul-2012 12:06
Nope. It wasn't that. There was a drop in current a short time after turning off, coinciding with a relay click, but the current draw after that was anomalously high. In the end I decided that the issue was probably instrumentation, and that it really wasn't worth the effort of pursuing.

kiwitrc

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Reply # 648985 1-Jul-2012 12:19
xarqi: Nope. It wasn't that. There was a drop in current a short time after turning off, coinciding with a relay click, but the current draw after that was anomalously high. In the end I decided that the issue was probably instrumentation, and that it really wasn't worth the effort of pursuing. PM me if you like as I can check your meter against a calibrated standard.

stuzzo

512 posts

Ultimate Geek

Reply # 648990 1-Jul-2012 12:27
xarqi: Nope. It wasn't that. There was a drop in current a short time after turning off, coinciding with a relay click, but the current draw after that was anomalously high. In the end I decided that the issue was probably instrumentation, and that it really wasn't worth the effort of pursuing. Yes, I see it was high even when you pushed the power button, sorry. Still, quite a strange result I thought. Even the rival "Smart" TVs like Samsung go to standby power pretty quickly.

xarqi

709 posts

Ultimate Geek

Reply # 649044 1-Jul-2012 13:54
kiwitrc: xarqi: Nope. It wasn't that. There was a drop in current a short time after turning off, coinciding with a relay click, but the current draw after that was anomalously high. In the end I decided that the issue was probably instrumentation, and that it really wasn't worth the effort of pursuing. PM me if you like as I can check your meter against a calibrated standard. Thanks for the offer, but the "meter" I used was a $14 ELTO jobbie from The Warehouse, and the problem is likely to be that it just doesn't handle anything at all tricky (reactive loads, complex waveforms, whatever the terms are) too well. With nobody else reporting problems (and having better test gear), and with a suspect meter, I'm content that there isn't really an issue here.

kiwitrc

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Reply # 649055 1-Jul-2012 14:08
Yeah there is cheap test gear and good test gear, but rarely good cheap test gear.

merlinz

36 posts

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Reply # 680233 1-Sep-2012 22:03
Excuse my waking up this old thread but I just bought one of Belkin's "Conserve Insight" power meters and am finding that it is giving readings that seem quite believable (i.e. generally consistent with expectations which are largely based on published specs of the various gadgets I've tried it on). It shows our Panasonic plasma (GT30) is drawing less than 0.5W once it goes into standby (i.e. after the relay clicks off). NB the meter doesn't give you accumulated KWH readings, just instantaneous or average consumption rate.

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