On Jun 13, 4:51 pm, "Zephyr" an address @ some place .com wrote:
Hey folks,

I'm curious about power consumption of things like the power supply for my
dell laptop
its and AC/DC adaptor, and when the unit is charging my laptop it gets quite
warm.
from that I infer that its using a fair amount of power.

now, if I leave it plugged into the wall, but remove the laptop, it does
not heat up, but.
there is a little light on it that indicates it is receiving power.
aside from that little light, is it using any significant amount of power?
The label on the unit says the input is 1.5a

same question goes for my cell phone chargers 0.2a

I understand that some of these things do use power constantly, but... how
much?

I found this link but it doesn't get into the Nitti gritty I was looking
for

http://gizmodo.com/gadgets/gadgets/c...mpire-slayer-a...

Dave

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Dave: There is not really enough info/numbers in the original posted
question to calculate; but here is an attempt.

Answer: Very little.

Here's an assumption. If it use 100 watts while lap-top charging it
probably uses less than 10% of that while not charging. That is less
than 10 watts. And 10 watts is probably a bit of an overestimation any
way.

Any more than that the charger alone would get slightly warm all the
time! Something like the amount of heat from one of those on-all-the
time night lights which IIRC are often 7.5 watts.

10 watts for one hour is one, one hundredth of a kilowatt hour. Using
my cost of electricity (yours may be more or less) of about 9 cents
(all charges included) per kilowatt hour, it will cost about 0.09
cents for every hour that it is plugged in but not charging anything.

Make that say one tenth of a cent; in other words it will cost around
2 to 2.5 cents per 24 hour day that it is plugged in and not charging.
Hardly worth bothering about?

A 100 watt light bulb left on for the same 24 hours would cost about
20 to 25 cents. Again depending on you electricity cost.

In regard to the cell phone charger.

You do not specify if the 0.2 amps is the input or the output.
Assuming it is the input:
Approx 120 x 0.2 = 24 watts. But again that would while charging.
That's probably less than one quarter of what the laptop charger
needs, cell phone is much smaller isn't it? While not charging; again
it probably uses less than one cent per 24 hour day.

This sort of question by those who are ignorant of electricity,
although the info. is usually on the label somewhere, and most of us
'did it in science class in school?"; reminds one of the little old
lady who used to go round plugging up her electric outlets "To stop
the electricity from leaking out"!

One item that doesn't seem to be realized with all this saving energy/
conservation business is that any lost heat from using less efficient
devices helps heat the house. We live in a cool area of North America
where every month of the year requires some heating, in our case
electric heating. We don't need or use air conditioning at all. So the
lost heat from much cheaper (about 25 cents each) non CFL light bulbs
etc. merely reduces electric heating! Our bathroom, for example, is
heated almost entirely by the six 40 watt bulbs above the vanity. Only
in coldest winter does the 500 watt baseboard electric heater operate!