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Whatever you call it, the humble AC adapter, external power supply, plug pack, plug-in adapter, domestic mains adapter, line power adapter, wall wart, or power brick is due for significant changes next month.
The U.S. Level VI energy-efficiency regulation, aimed at energy savings in external power supplies, goes into force on February 10, 2016, and will impact all OEMs selling into the U.S. market. The European Union (EU) also is expected to harmonize with the new efficiency standard.
This article includes a quote (& pun) from one power supply vendor,
"It's a two-pronged approach," said Johnson. "The regulation addresses active mode when the adapter is powered up and supplying power to the end product. Under the regulation, efficiency is increased by roughly five percent."
But the big change is at no load when the adapter is plugged into the wall – like a cell phone charger – and nothing is connected to it, Johnson added. "Power consumption at Level IV was .5 watt and at Level VI it's decreasing to .1 watt, which when you talk about the millions of adapters in the market it's significant in power savings."
Another article can be found at http://www.metlabs.com/blog/energy-star-2/external-power-supplies-must-meet-level-vi-energy-efficiency-requirements-for-u-s-doe-by-february-2016/
US Department of Energy has an information page with several linked documents
https://www1.eere.energy.gov/buildings/appliance_standards/rulemaking.aspx/ruleid/28
"Rulemaking for Battery Chargers and External Power Supplies Energy Conservation Standard"
(Score: 0) by Anonymous Coward on Saturday January 02 2016, @01:02PM
wow, i didn't know that.
i always thought that A/C-2-DC wallwarts don't use any electricity if no device is connected on the DC side!
so wouldn't it have been better to put the converter straight into the device itself ... then it would become
obvious that it doesn't draw any electricity if not connected to the wall-socket?
kindda like unscrewing a light-bulb if you want to turn it off ^_^
or .. damn ... just a little on-off button/switch on the wallwart (with a 'lil lamp that sayz it's on)?
(Score: 0) by Anonymous Coward on Saturday January 02 2016, @01:09PM
> so wouldn't it have been better to put the converter straight into the device itself
And double the weight of your phone. And increase the chance of the device failing.
> or .. damn ... just a little on-off button/switch on the wallwart (with a 'lil lamp that sayz it's on)?
Lots of wallwarts are squirreled away out of sight out of mind or at least a PITA to get access to. Automating them to do the right thing fixes the problem in all cases because people are lazy.
(Score: 0) by Anonymous Coward on Saturday January 02 2016, @02:41PM
There's two types of wall-warts.
The first one uses a big 60Hz transformer to reduce voltage, then whatever rectifier and possibly voltage regulator seem appropriate to the application. These have rather high power consumption when unloaded, and relatively poor efficiency when loaded, too. Of course, they're practically unheard of the past decade or more.
The second type is a switch-mode power supply, which are not only smaller, cheaper, and more efficient at the same design load, but also can easily have very low power consumption when unloaded. Even designs where unloaded power consumption isn't a design criteria are typically still much better than any transformer-type wall-wart.
Your belief of zero no-load consumption can be a practically correct approximation, but it is an approximation, and its usefulness depends not only on actual no-load power consumption, but also on duty cycle. Consider a SMPS with no-load consumption equal to 5% of rated load. For a device that functions 8 hours a day, and is left plugged in the other 16 hours, neglecting the unloaded consumption only gives about a 10% error, but for a device used 30 minutes a week, the unloaded consumption is an order of magnitude higher than the in-use consumption. (Even if we go to 1%, as for a 10W power supply complying with the new 0.1W standard, no-load for 167.5 hours is over 3x in-use for 0.5 hours.)
(Score: 2) by gnuman on Saturday January 02 2016, @05:07PM
The first one uses a big 60Hz transformer to reduce voltage, then whatever rectifier and possibly voltage regulator seem appropriate to the application. These have rather high power consumption when unloaded, and relatively poor efficiency when loaded, too. Of course, they're practically unheard of the past decade or more.
https://en.wikipedia.org/wiki/Switched-mode_power_supply [wikipedia.org]
It seems that transformers remain. A SMPS does not remove the need for a transformer. On the contrary, transformer is a requirement to have an isolated circuit.
(Score: 0) by Anonymous Coward on Saturday January 02 2016, @07:40PM
Of course. That's why I said the non-switch-mode type has "a big 60Hz transformer", as opposed to the little >kHz transformer in a SMPS.
(Score: 0) by Anonymous Coward on Saturday January 02 2016, @04:58PM
Simple way to tell if a wall wart is drawing/wasting more than a watt or two of power (with no load connected) -- see if it's warm. The older transformer types were always warm if left on (load or no load). Also, transformer types are heavier -- the transformer is iron with copper windings.
(Score: 3, Informative) by sjames on Saturday January 02 2016, @06:41PM
Many electronics manufacturers just buy the wall warts and have no in-house people who even know how to get something UL listed.
(Score: 2) by Hyperturtle on Saturday January 02 2016, @09:04PM
Whoa -- where have you been for the past 20 years.
You need to unplug those or put them on a power strip or something. Those things generate heat, and depending on conditions, even make noises as they sizzle internally... you don't seem the type to have a killawatt reader.
I can assure you that there is a good reason why wallwarts are called vampires.