
Phone chargers - the truth - nickb
http://www.inference.phy.cam.ac.uk/sustainable/charger/
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huhtenberg
I am not a physicist, but this rant sounds pretty clueless to me.

If I recall high school physics correctly, plugging an _idle_ transformer into
an AC outlet _reduces available power_ of the current. This is because it
affects a shift between I and U and thus causes the wattage (which is I x U
integral over their period) to go down. It may also _consume_ the energy if
its assembly of a poor quality.

This applies only to the traditional transformers, those with a coil inside. I
am not sure what a modern phone charger has inside.

~~~
jwilliams
This is generally called the power factor - if you have a purely inductive
(your coil example) or capacitive load have a pf approaching 0. A purely
resistive load is 1.

Phone chargers and similar usually have pretty bad pf - but not because of the
above, but because they are designed to take energy in short pulses (they call
this a non-linear load).

Energy isn't really consumed by this, but it does affect the way the
distribution system is designed and operates (which may involve downstream
energy waste).

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jwilliams
Every little bit helps. 0.01% of energy is still a lot of energy... Besides,
what it does indicate is a culture around energy.

Another problem is a proliferation of chargers. Instead of having one plugging
in, people have two, or three, or a dozen.

If there were better standards, you could have fewer, bigger, more efficient
chargers.

I'm not sure if this is addressed in USB3.0 (I'm pretty sure it's not), but
there is an opportunity there to bring in a universal charger - that is smart
and efficient at the same time.

~~~
bestes
It creates a culture of nonsense. How can a message based on facts get through
this noise?

~~~
jwilliams
What's factually incorrect? When you have a charger plugged in with nothing
connected, then 100% of the energy consumed goes to no useful work.

Did you see the original BBC article? It also doesn't claim that chargers are
a massive sink of energy - it says that it's an indication of a culture that's
not energy-aware.

[http://www.inference.phy.cam.ac.uk/sustainable/images/Britai...](http://www.inference.phy.cam.ac.uk/sustainable/images/BritainStandby.png)
_Leaving mobile phone chargers plugged in and lights on were the most common
energy-wasting habits_.

