Do "wall warts" use up much power?

Run_to_da_hills

Looking around the house there is a heap of wall warts i.e. phone chargers, radio system chargers, telephones, printers, cameras, battery Chargers, game consols, GPS & PDA's, Computer Speaker Systems etc. They are all over the place, do these use up much power? Some need to be left in, others can be plugged out when not in use.

blackbox

If you want to know the answer, read the manual that came with them. If it's not stated there, put a meter on them.

You'll probably find they use very little power.

Alun

It's unlikely that any manual will tell you the no-load power consumption of something like this, and the power ratings printed on the devices themselves are pretty irrelevant when considering the no-load consumption as well.

Real life measurements carried out only minutes ago by yours truly on a bewildering array of different 'wall warts' in my possession indicates that most of them consume something like 20mA when nothing is connected to them. It's up to you as to whether you consider this significant or not.

EDIT: correction - I was measuring current not power .. my plug-in power meter has a pretty difficult to read display and I got confused. However that didn't translate into what I was expecting on the power display (i.e. 0.02*230=4.5W) in fact the power display hardly registered at all some times briefly showing 1W for a second (it has a resolution of 1W), but then I noticed that the power factor displayed was only around 0.25 (see http://en.wikipedia.org/wiki/Power_factor) which would explain it.

McSandwich

Interesting article on this:

http://www.pcpro.co.uk/columns/163650/technolog.html

McSandwich

Alun wrote: »

0.02*230=4.5W

Assuming that the psu outputs 12v, this should be 0.020*12=0.24 watts

Alun

McSandwich wrote: »

Assuming that the psu outputs 12v, this should be 0.020*12=0.24 watts

I was measuring the 0.02A on the AC side I've got one of those plug-in power meters that reads volts, frequency, watts, kWh and can even be programmed with the cost per kWh and output the actual cost of the usage over a time period.

McSandwich

Alun wrote: »

I was measuring the 0.02A on the AC side I've got one of those plug-in power meters that reads volts, frequency, watts, kWh and can even be programmed with the cost per kWh and output the actual cost of the usage over a time period.

Ah, that makes sense, especially in relation to the power factor! What brand is your power meter? I've been thinking about getting one of those for a while..

Alun

McSandwich wrote: »

Ah, that makes sense, especially in relation to the power factor! What brand is your power meter? I've been thinking about getting one of those for a while..

I got it in Lidl a couple of years ago. No sign of an actual manufacturer's name on it apart from some company Called Paget trading in the UK who seem to be the importer/wholesaler. I believe you can get something similar in Maplin though.

AngryHippie

Switch the socket off at the wall if you're not going to be using it for a day or two, Plug out your phone charger when the phone is charged and switch off your tv from standby at night, same for PC's. After that you can sleep easy....

blackbox

AngryHippie wrote: »

Switch the socket off at the wall if you're not going to be using it for a day or two, Plug out your phone charger when the phone is charged and switch off your tv from standby at night, same for PC's. After that you can sleep easy....

You've got to keep things in perspective. You will save more energy by unplugging your electric heater 5 minutes earlier or boiling the kettle one time less per day (not to mention avoiding use of a tumble drier if you can air-dry your clothes).

Every little helps, but if you want to seriously save energy you need to focus on the heavy consumption items.