Posted on 04/06/2016 9:05:30 PM PDT by Swordmaker
Ever thought how much your iPhone (or Android smartphone) is costing you in power a year to charge? What about your tablet or laptop? Or your ebook reader? And do wall warts consume power when there's nothing connected to them?
If you're anything like me, you have a number of gadgets within arms reach that are either on charge right now, or will need charging at some point during the day. Maybe it's a smartphone or tablet, or a laptop, or a wearable. They all have one thing in common - they need power.
And that power costs you money. But how much money?
Over the years I've seen a lot of estimates as to how much power smartphones, tablets, laptops, and other devices consume, but it has always concerned me that these numbers either appear to be pulled out of the air, numbers copied off another website that pulled them out of the air, data derived from published battery capacity figures, or are figures derived from lab testing as opposed to real-world usage.
As regular readers will know, I'm a big fan of real-world testing. The only drawback of real-world testing is that my "real world" is going to be different to your "real world," which means that your mileage can, and probably will, vary. But, as long as a few variables are nailed down, these differences shouldn't be too great.
(Excerpt) Read more at zdnet.com ...
Watt difference, at this point, does it make?
“This is because when a “wall wart” has no load they use very few watts as measured by the watt meter but under no load many actually are using more than twice the amperage than what one would expect from the watt meter.”
I would like to hear your explanation for a device can use more amperage when there is no load. Use details. I will understand.
How did you get that wonderful low pricing?
Correct. It is the ratio of real power flowing to the load vs the apparent power it took to get that flow to the load. The difference between the two is what's used up in reactive loads (the imaginary part of the equation) with them being either a capacitive or inductive load. It still costs money to generate enough apparent power to get the real power delivered so managing the reactive load brings the power factor closer to 1.
When I worked in a pulp plant as an engineer, we generated a lot of our electricity from superheated steam powering turbines. The plant contained thousands of induction motors and we often had to bring in banks of big capacitors to balance out the reactive load - overall efficiency in real power production - cost savings.
Didn’t YOU see!!! This power consumption is related to the release of CARBON!!! Several ounces a year!!! Unplug those unused chargers. We CAN save this planet!!!
Best answer!
Gaffer gives a pretty good explanation in a following post. I have similar real world experience working in a lumber mill for nearly ten years as a millwright. But I am not an electrical engineer so you would be better off looking it up to get the best explanation.
But I will attempt to give a short and probably not a very good explanation: When we are first taught about electrical theory we learn about DC circuits with resistive loads. In that circumstance watts = amps x volts.
But with AC power it is more complicated, there are resistive loads, inductive loads and capacitive loads. Inductive and capacitive loads are known as reactive loads. They cancel each other out if they are in the same circuit, but if they are not cancelled they measure as additional AC volt amps added to your conventional resistive load. This is why AC power is measured in both Volt Amps and Watts. Power factor is the proportional difference between the two.
If inductive loads, most often from motors and transformers are not cancelled by using capacitance they can cause excessive amperage in the wires supplying the electricity. It is enough of a problem for utilities that businesses which traditionally use a lot of inductive load and have “poor power factors” have metering which measures power factor and penalizes them with higher electrical rates if they do not correct it with capacitors.
On a theoretical basis inductive loads impede the AC wave form and adding capacitive load corrects for it.
I am sure my attempt to explain has not really helped. If you read up on it from people who have a deep understanding, or take a college quarter of AC electrical theory then you will probably get it. Sorry for my incomplete explanation.
The overall mathematical upshot of it all is that to deliver 100% of the source to a load for maximum transfer of power (i.e., ideally ‘matched’) if there is a reactive component there has to be some accommodation for a modification to the circuit that creates a complex conjugate to bring the overall equation to only “real” terms (imaginary terms balanced out to zero).
I understand what you mean since I have had to deal with this in real life as you have; I think that many others might have a difficult time understanding the theory behind the explanation.
The right triangle. The hypotenuse is what you pay for. The X axis is what you get that does work. The Y access does no useful work. Adding complex conjugate zeros the Y axis.
Drive home is 1 hour, laptop, tablet and phone are plugged into truck chargers ..... get home, all charged. 4 maybe 5 hours of assorted use then to bed. Next morning go to work, charge gadgets on drive to work, then plug in as needed at work. Full recharge on truck chargers on way home.
Rinse, repeat , set on spin cycle and never spend your own money to charge your internet implements of death and destruction...........:o)
Now compute how much of a hit you take on your gas mileage from having to overwork that alternator every day.
So if I turn off my radio I get better mileage ???.......:o)
Typical non-switching power supply wall warts (the heavy copper coil transformer kind) use essentially the same power with load applied or not.
Use kill-a-watt etc with my inverter loads all the time.
Use switching power adapters whenever possible, of course.
Those positioned as such might just propel one down the road with the engine off....LOL !
Man I despise that stuff, crazy loud and ya feel it before ya hear it....... sort of like getting shot !
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.