On 11/5/2019 12:26 PM, John McGaw wrote:
<snip>
> Very simplistic test: if the wall wart is heavy (i.e. has a big iron
> transformer inside like the ancient Netgear 12V units) and/or is warm to
> the touch when there is no load (again, like the ancient Netgear 12V
> units) then it it is using power inefficiently. Most of the lightweight
> warts using switching supplies are relatively efficient when there is no
> load. If the unit is warm when unloaded that is a dead giveaway of power
> waste since heat has to come from somewhere.
Read page 68 of
<
http://www.inference.org.uk/sustainable/book/tex/sewtha.pdf>
--------------------------------------------------
"The truth about chargers
Modern phone chargers, when left plugged in with no phone attached, use
about half a watt. In our preferred units, this is a power consumption
of about 0.01 kWh per day. For anyone whose consumption stack is over
100 kWh per day, the BBC’s advice, always unplug the phone charger,
could potentially reduce their energy consumption by one hundredth of
one percent (if only they would do it). Every little helps!
I don’t think so. Obsessively switching off the phone-charger is like
bailing the Titanic with a teaspoon. Do switch it off, but please be
aware how tiny a gesture it is."
--------------------------------------------------
There are power strips with individual switches for those really
obsessive about that 0.01KWH per day, i.e.
<
https://www.aliexpress.com/item/32884477960.html>.
Also consider that in cold weather that 0.01KWH is not really wasted,
it's heating your home, but in hot weather your air-conditioner is
working harder (except in the U.K. where they have not yet discovered
air-conditioning).
Also read <
https://michaelbluejay.com/electricity/vampire.html>
He mentions set-top boxes. I decided to measure my Comcast set-top box
vampire power. Indeed he is correct. My set-top box (no DVR) draws 11.3W
when off, and 11.9W when on. That's 1KWH every four days or so, or
about 100KWH/year. At 25¢/KWH that's $25 per year.
Plugging in phone charges to measure standby power is difficult. While
that book mentions 0.5W standby, my Ubio inductive charger draws 0.0W on
standby, about 6.5W when charging my iPhone with its Qi case (my iPhone
doesn't have built-in inductive charging). Obviously it's drawing
something when the phone isn't being charged, but my "Kill A Watt"
device only measures down to 1/10 of a watt.
> My biggest gripe is the vast number of different voltage/connector
> combinations in the wild. I've got at least four different sorts which
> have multi-pin connectors, all incompatible either physically or by
> voltage ratings, which I've got in a box in the closet of computer shame
> in the basement. When I do need one of them to power an old external
> drive, for example, it can take a half hour to find the right unit and
> even then it is sometimes guesswork. Of course with the rest of them it
> is a matter of voltage/current/inside diameter/outside diameter...
When I take new device out of the box I immediately attach a tag
indicating what it's for.
We have another issue in California now. Because solar has become so
popular, at peak production time houses are feeding more power back onto
the grid than the grid can handle plus there's no good way to store the
vast amounts of excess electricity being generated. The grid was not
designed for two-way transmission of electricity, nor was it designed
for storage. The utilities are changing the payment structure, moving
the peak payments you get for solar to discourage too much power from
being fed back onto the grid at peak production time.
It used to be that it was really stupid to have batteries like a Tesla
Powerwall if you had solar because you didn't want to be using your
valuable KWH to charge a battery, you wanted to be selling them back to
the utility (in California we get the RETAIL value of KWH as credit, not
the wholesale value). But now it's beginning to make sense to have
batteries for financial reasons, as well as to deal with the PSPS
(Public Safety Power Shutoffs). What you're not allowed to do is to
charge your batteries with solar during peak solar production time then
feed that electricity back onto the grid during peak value time.