AV system standby power eliminator

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timmmay

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#1735097 12-Mar-2017 09:15

I measured the standby usage today. 230V approx, 0.105A (105ma), and 4W. With the sub and fans on that rises to 16W. Not worth worrying about if that's accurate, just want to get the fans to turn off.

The thing that confused me is I thought watts = volts * amps. 235V * 0.1A = 23.5W, not the 4W the device was reading. What's incorrect, my understanding or the device? It looks like the attached picture.

richms

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#1735104 12-Mar-2017 10:13

Volts times amps is VA, which matters when sizing transformers etc, the real power is the multiplication of the 2 waves, which not many power meters do very well. They will give you a power factor which really just shows the difference between the VA and the actually wattage.

But ontop of powerfactor, when the current waveform is not a sine wave - so with anything that has active electronics pretty much there is way more to it than just a simple power factor number, so even the fudges that these meters do isnt going to be totally accurate. I have had PCs that show more power on the cheap meters when off and just powering the 5v standby than when actually on and idle. Just because of the terrible waveform of the smaller of the 2 power supplies in the PC.

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timmmay

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#1735107 12-Mar-2017 10:20

Any idea how much power the AV system is actually using in standby? Or is it impossible to say from this information? My older meter gave me quite different results.

richms

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#1735108 12-Mar-2017 10:26

You need some seriously pro kit to get a real reading, but its down in the who cares territory so I wouldnt bother.

When a friend was wanting to deploy some wifi kit into other peoples places an eternity ago we tried consumer meters on them and had stupidly varied results often less than measured on the DC side of the power supply. Rented a crazy priced HP analyzer and it gave results right on with what was expected with the DC side of the power supply plus a bit for inefficiancy of the supply, stable and not jumping all over the place like the cheap meters were.

If you want to see an "appliance" that wastes a crapload of power for very little gain then look at an aquarium.

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Jase2985

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#1735164 12-Mar-2017 11:59

either way the 16w or 24w is along way from the 100w you mentioned earlier. how are the fans still going if the unit is in standby? never seen this before

timmmay

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#1735216 12-Mar-2017 12:33

Yeah, not sure why it's so different from my last measurements. Different meter, it shouldn't be that different.

Fans are something I added myself to prevent the receive and cabinet overheating. Three 12V case fans, two in the back of the entertainment system, one sitting direct on top of the Onkyo receiver to draw air through. Powered by a simple 12V PSU.

richms

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#1735218 12-Mar-2017 12:35

perhaps grab one of those "eco" power strips that cut power to the other outlets when the load on the main one goes low enough, put the amp on the main outlet and the fans and other crap on the switched outlets?

Richard rich.ms

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timmmay

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#1735233 12-Mar-2017 13:09

I built a little black box with a solid state relay that takes the USB from the TV, cutting off power to the fans when the TV goes off. The sub has an auto power off option, it's just a bit rubbish at coming back on. Given the load now looks quite low I'm not sure if it's worth the cost. If I see one of those boxes cheap I might grab one.

It might've been that I measured the load back when I had a cable box, Telstra or Sky or something. Those things are notorious power hogs, even when off.

Maxcat

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#1756110 4-Apr-2017 09:13

timmmay:

I built a little black box with a solid state relay that takes the USB from the TV, cutting off power to the fans when the TV goes off. The sub has an auto power off option, it's just a bit rubbish at coming back on. Given the load now looks quite low I'm not sure if it's worth the cost. If I see one of those boxes cheap I might grab one.

It might've been that I measured the load back when I had a cable box, Telstra or Sky or something. Those things are notorious power hogs, even when off.

I do it automatically with one of these. Turn off the master and the slave sockets turn off also. Turn on and they come on.

In my system main amp/receiver turns on outboard processors (not equipped with 12v triggers). It also turns off other devices that are on standby and only used when this system is on.

It is a JACKSON 6 way Energy Saving Power Board - $21 delivered.

Arlec also makes one:

timmmay

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#1756114 4-Apr-2017 09:25

Maxcat:

I do it automatically with one of these. Turn off the master and the slave sockets turn off also. Turn on and they come on.

In my system main amp/receiver turns on outboard processors (not equipped with 12v triggers). It also turns off other devices that are on standby and only used when this system is on.

It is a JACKSON 6 way Energy Saving Power Board - $21 delivered.

Arlec also makes one

Interesting, thanks. I guess that means one device stays on all the time, so you choose the device with the lowest standby power.

We're using a basic switch (eco switch) I had for something else, manually turning it on and off. It's a little bit annoying though.

Save Barn doesn't have that product right now, but has the Arlec for $45. PB has the Jackson for $30 plus shipping, none in stores.

Maxcat

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#1756117 4-Apr-2017 09:32

timmmay:

Maxcat:

I do it automatically with one of these. Turn off the master and the slave sockets turn off also. Turn on and they come on.

In my system main amp/receiver turns on outboard processors (not equipped with 12v triggers). It also turns off other devices that are on standby and only used when this system is on.

It is a JACKSON 6 way Energy Saving Power Board - $21 delivered.

Arlec also makes one

Interesting, thanks. I guess that means one device stays on all the time, so you choose the device with the lowest standby power.

We're using a basic switch (eco switch) I had for something else, manually turning it on and off. It's a little bit annoying though.

Save Barn doesn't have that product right now, but has the Arlec for $45. PB has the Jackson for $30 plus shipping, none in stores.

One device can stay on (Freeview set top) and the rest on/off 'on-demand'.

Go to Elive.co.nz

https://www.elive.co.nz/jackson-6-way-power-board-cd1424.php

timmmay

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#1756118 4-Apr-2017 09:37

Good link, thanks. I'll check plug count tonight, and whether they'll fit into that closely spaced board :)

Maxcat

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#1756123 4-Apr-2017 09:43

Great! Hope it works at your place. I t really sorted things out at mine.

I'm going to try the Arlec as well for main TV room due to the two 'always on' sockets.

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