

Is it a sin to leave your cell phone plugged in overnight? - chwolfe
http://www.slate.com/toolbar.aspx?action=print&id=2232195

======
skolor
Correct me if I'm wrong, but the cell phone is going to be using about the
same power when its plugged in and fully charged as it does when it is
unplugged. The difference is only that the power is coming from the outlet,
rather than the battery in the phone. Without some calculations on how much
would be drawn from the battery, simply from having the phone on over night,
its hard to say what kind of power savings are available. I would guess its
next to nothing, even less than they make it out to be in the article.

------
mseebach
It says that an idle, but plugged in charger pulls around 2.3 watts. I always
thought that switching chargers (most modern celphones comes with those) were
able to switch themselves off (something with keeping a capacitor charged to
kick the circuit online once something starts drawing power).

~~~
electromagnetic
This is rather easy to tell. Leave your charger unplugged for an hour and feel
how cold the plastic gets, then plug it in to let it idle. If you have a
switching charger it should stay around roughly the same temperature as when
it was unplugged, if it feels like it gets warmer then that means it's in idle
and not switched off.

The flat-form transformers used in most cell chargers are rather inefficient,
so the temperature difference tends to be more than expected. However when
you're dealing with ~9W maximum, it's likely more energy efficient to produce
a less efficient transformer than consume extra time on the production line.

~~~
mseebach
Yeah -- and there also size (very small), weight (very light) and sound (coils
hum at 50/60 hz, the switching ones "whine").

But I wouldn't think the lack of heat that I can feel means that it doesn't
waste 2.3w?

~~~
moe
If by "whine" you refer to a very high pitched noise (akin to a TV tube) then
I'll take a non-switched one every day.

I have two such mosquito-infested powerbricks here, emitting a constant high-
pitched noise each, and it's _royally_ annoying. The charger for my DECT phone
emits it when the handset is not sitting on it and one of my two BenQ screens
(ironically both the exact same model!) emits it when turned off.

This may be an avoidable production bug but when it strikes it's plain out
horrible. I had to ban that DECT-charger from the living room because the
sound would drive us nuts...

(And yes I should have returned both items as defective but on the phone I was
too lazy and on the screen the noise only started after it was about 2 yrs
old)

~~~
mseebach
It is, and I've had some of the bad chargers as well. Usually, however, I have
to press my ear against the brick to hear it at all, and have really good
hearing.

------
ajb
I think we need a new unit, the 'hamsterpower', for levels of energy use which
are not worth thinking about. A hamster can generate about 0.15W, so rounding,
I guess we could define 1 hamsterpower = 0.1W.

<http://otherpower.com/hamster.html>

[http://en.allexperts.com/q/Science-Kids-3250/Hamster-
Power.h...](http://en.allexperts.com/q/Science-Kids-3250/Hamster-Power.htm))

------
edw519
_Would it better for me to charge my electronics during my morning commute, by
plugging them into the car charger?_

A commute long enough to charge your electronics is probably a bigger "sin"
than a cell phone plugged in overnight.

~~~
jrockway
Saving the environment is a task that's too difficult for one person to
understand, so anything that seems slightly inconvenient is good enough to
satisfy most people's "needs". Changing when you charge your cell phone is a
lot easier than planning your life to be lower-impact.

(I love all the SUVs filled with one grocery bag at Whole Foods. Do you really
think that buying some locally-grown organic carrots offsets the energy you
spent driving your military vehicle 3 blocks?)

~~~
bmj
Indeed.

"Forget Shorter Showers"
([http://www.orionmagazine.org/index.php/articles/article/4801...](http://www.orionmagazine.org/index.php/articles/article/4801/))
points out that perhaps we've duped to think that energy shortages/waste are
_our_ fault, when, in fact, it's industry, large-scale agriculture, and our
military that are the biggest abusers. Of course, this isn't an excuse to not
be lower impact ourselves (and perhaps not purchasing products that support
certain industries), but we can't be fooled into thinking that changing our
charging habit is going to save the environment.

~~~
maryrosecook
For more from the wonderful Jensen on how abusive our culture is, read A
Language Older Than Words ([http://www.amazon.com/Language-Older-Than-
Words/dp/189395603...](http://www.amazon.com/Language-Older-Than-
Words/dp/1893956032)). If you can look past the absurd stuff about talking to
animals, there is a lot to be learnt from it.

------
NathanKP
I recently got the Kill-a-Watt to test electricity usage by different devices.
My laptop uses a mere $13 worth of electricity per year (And that is assuming
that I leave it on constantly rather than closing the lid and letting it
hibernate). Modern computing devices have become so efficient that they make
little impact. If you want to save energy it is better to look at your
refrigerator, stove, AC, and the other major electricity burners.

~~~
zandorg
I have a home music production studio with 15 devices (mixers, synths,
processors, amp, laptop, ancient PC). I used a measuring device and even
though the PC is supposed to use 250 watts or so, the entire studio is only
468 watts! This is a cost of around 4.68 pence an hour (I think a kilowatt
here is 10 pence), which isn't bad when a commercial studio costs at least 10
pounds.

I'm not a US citizen but this helps you calculate (each value is the cost of a
kilowatt):

<http://www.eia.doe.gov/cneaf/electricity/epm/table5_6_b.html>

------
leviathant
I leave my phone plugged in overnight, and when I get to work, I have it
plugged into the USB drive on my computer. On the occasion where I'm driving,
I've got an Alpine stereo with an iPhone adapter, and a mount for my phone, so
I leave it plugged in there.

I haven't done any hard numbers, but my battery capacity doesn't seem like
it's worn down from when I got the phone over two years ago.

Nonetheless, there are definitely more important things to worry about whether
you're looking to cut back on your electric bill, or are trying to be more
'green.'

------
asciilifeform
1) conservation of energy - if the phone is switched on, it is drawing
current. If the latter is from the battery, you will pay for it (plus the
charger's and DC-DC converter's inefficiencies) later.

2) battery wear - how much energy does it take to manufacture a new Li-ion
pack?

------
ido
It seems like the phone 'knows' when it is fully charged, so why don't phone
manufacturers simply disable charging once it is full?

~~~
chrisb
They do.

But the switching power supply that regulates the mains voltage to 5v (or
whatever is required) is always on, and although they are extremely efficient
the loses do add up.

Arguably it should be possible for the phone to switch off the supply _before_
the switching power supply, but this will add complexity and cost to the
product. And because the power supply is normally seperate from the phone some
kind of signalling from phone to power supply would need to be implemented.
Again adding complexity and cost.

As mentioned in the article, <http://www.withouthotair.com/> is well worth the
read, and will help you understand what is actually worth doing to lower
energy use and carbon footprint. (The book is considerably better than the
appearance of the website would suggest!)

~~~
drothlis
I will second the recommendation of the "Sustainable Energy – without the hot
air" book, and mention that it is free to download from the above site. It
looks at the debate from a technical perspective, with extensive appendixes
containing the author's calculations.

One thought from the book that struck me is that all the batteries in the
(eventual) nationwide fleet of electric vehicles, could serve to smooth out
the fluctuations from renewable energy sources. The author envisions battery-
exchange stations as commonly-found as petrol stations are today.

------
tocomment
My iPhone stops charging when it's full. (I'm going to buy a killawatt and
prove it soon)

~~~
ovi256
This has nothing to do with the cell phone, nut with the charger. Even if the
phone stops drawing current, old-style transformer based chargers still draw
power from the grid. Newer switching power supplies do not - at all, as the
link above [1] showed.

[1] <http://www.inference.phy.cam.ac.uk/sustainable/charger/>

------
biohacker42
I expect the MSM to try and keep their audience entertained with this inane
_charging your electronic crap is killing the earth_ meme. But I would think
HN is the one place this meme would not be able to infect. Am I wrong?

~~~
invisible
I don't know whether to point out the article is arguing against that it's
killing the earth or question if you even opened the link before responding. I
thought hn was the one place the latter was avoided (and hey, why comment if
you disapprove of the thread's popularity?).

~~~
biohacker42
I did read the article, but already knew the meme is stupid and wrong and
thought the same of the HN readership, thus I'm surprised to see it in any
form, pro or against.

And I comment when I disapprove of a thread because the _flag and shut up_
mantra has never sat right with me. I prefer to explain why I dislike
something.

~~~
invisible
If all you did was explain why you disapproved of things you'd be giving undo
(reasonably) attention towards something you felt was stupid. Why waste the
time when you're not obliged? That's all I'm curious about - you could find
another topic more important and make that topic popular.

~~~
biohacker42
It's a (perhaps undo) attempt to purge non-HN type stories from HN. It's a
kind of not very useful or productive hobby.

------
gojomo
It's disheartening that the Slate analysis does not calculate the approximate
cost in dollars of alternate leaving-things-plugged-in strategies.

Even when prices are distorted by non-competitive markets, subsidies,
regulation, and so forth, they remain vaguely related to the actual
opportunity costs of a path of action.

According to this chart, the average retail price of a kilowatt-hour in the US
varies from about 8¢ (West Virginia) to 22¢ (Hawaii).

<http://www.eia.doe.gov/cneaf/electricity/epm/table5_6_a.html>

So given Slate's estimate that leaving a phone plugged in an unnecessary 8
hours every day for a year would use 6.5 kWh, we're talking about a cost over
the whole year of 54¢ to $1.43.

Is a full year of fussing with the charger to minimize hours-plugged-in worth
a savings of $1.43 in time or energy? If once, over many years of following
this strategy, it means your phone dies at an inopportune moment, was it worth
the years of savings?

We spend energy all the time for convenience, and $2/year for not having to
micromanage a device that's supposed to make life easier is a bargain.

