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View Full Version : kill a watt power usage meters in NZ



utopian201
08-12-2008, 12:04 PM
Hi
Is anyone aware of any 'kill a watt' devices for the NZ market? They are basically a small watt meter that plugs into the mains power, and then you plug your device into the device. And LCD readout tells you how much power it is pulling from the socket.

I'd like to get one so I can find out how much power my PC, monitor and other appliances are really drawing.

pctek
08-12-2008, 12:46 PM
http://www.jaycar.co.nz/productView.asp?ID=MS6115&CATID=&keywords=power+meter&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=

qazwsxokmijn
08-12-2008, 01:04 PM
There's a bunch of others on Trademe that does basically the same stuff.

seltsam
08-12-2008, 01:46 PM
I've got an EMA-1 that looks like the Jaycar one but cost half the price from the local hardware shop. It gives unbelievably low wattage readings on the PC and monitor, which I suspect is due to their switch mode power supplies distorting the values somehow
On stuff like heaters it's OK.
Also, it won't register anything under 5 watts, so can't be used to check standby usage for many modern appliances.

rumpty
08-12-2008, 05:47 PM
I've got an EMA-1 that looks like the Jaycar one but cost half the price from the local hardware shop. It gives unbelievably low wattage readings on the PC and monitor, which I suspect is due to their switch mode power supplies distorting the values somehow
On stuff like heaters it's OK.
Also, it won't register anything under 5 watts, so can't be used to check standby usage for many modern appliances.

A decent wattmeter would have to do True RMS readings to give an accurate reading on a SM power supply. Do any of these cheapies specify they are True RMS?

qazwsxokmijn
08-12-2008, 06:05 PM
A decent wattmeter would have to do True RMS readings to give an accurate reading on a SM power supply. Do any of these cheapies specify they are True RMS?
Lol I just made a search on tm and this was the first compatible result:

http://www.trademe.co.nz/Business-farming-industry/Industrial/Electrical-equipment/auction-191606494.htm

Screw that! :D

Strommer
08-12-2008, 08:01 PM
I have one of these (http://www.dse.co.nz/dse.shop/493cc5b60279c7da2742c0a87f3b072b/Product/View/M7319) from DSE. $25. Works OK.

seltsam
08-12-2008, 08:34 PM
I have one of these (http://www.dse.co.nz/dse.shop/493cc5b60279c7da2742c0a87f3b072b/Product/View/M7319) from DSE. $25. Works OK.
Identical to mine.

qazwsxokmijn
08-12-2008, 08:56 PM
Identical to mine.
I'll drop by DSE tomorrow and pick one up then.

utopian201
09-12-2008, 09:44 AM
Are the $25 DSE ones the same as the Jaycar ones? They look externally similar, but I'm wondering is the accuracy the same?

qazwsxokmijn
09-12-2008, 03:17 PM
I just got one a few hours ago (the DSE one). My system is quoted at 167W idle, 250W full load. System specs on my signature.

utopian201
09-12-2008, 04:46 PM
Apparently they under report for things which use switching power supplies (computers, tvs, radios etc) and are only accurate for appliances with a resistive load (eg a kettle)

qaz: Do you know if it measures true RMS?

qazwsxokmijn
09-12-2008, 06:34 PM
qaz: Do you know if it measures true RMS?
No idea. :S

More or less it might report up to 30W under the real consumption, though, as after reading up others' and reviews of 4870-based systems, I found that I have about the same rating at idle, but less when loaded. Reviewers systems didn't have cases I think, so they don't have system fans and don't have any fancy lights which I do, which I predict would bump up power consumption by about 20-30W.

Still, I think I can safely say my PC consumes less than 300W at load and slightly less than 200W idle.

FYI, my fridge consumes 112W, and CRT TV 45W. Man I'm having fun with this thing! :p