Charger transformer plug-in's

[KE6DF]

I've often heard that one should unplug, when not in use, the little transformer plug in blocks that are used to charge cell phones and other battery powered devices.

I wondered how much power I was actually wasting leaving them plugged in.

I have one of these that came with my Kindle Fire tablet. It's output is a standard (small sized) USB connector so it can charge any USB type device.

I use it to charge my cell phone as well as the Kindle.

Anyway, I got out my trusty Kill-a-watt and plugged it in.

With nothing plugged into the charge block, I got zero watts used.

The current reading was 0.00.

So less that 10 ma. And less than 0.1 watt. (It read zero).

Plugging in the cell phone, I had about 3.5 watts drawn to charge the phone.

The power factor was about 0.6.

So, the bottom line is, at least for this transformer block, there is no reason to unplug it.

Perhaps they are designing these things better so the old recommendation to unplug them may not hold any more.

Dave

[N8ETQ]

Hey Dave,

  If they don't stay warm after recharging I don't usually mess
with them. I have noticed some stay pretty warm when idle
however. My drill charger is one that comes to mind.

/Dan   

[k4kyv]

Of course, if you unplug them when not in use, there is little chance that they will get zapped from a lightning surge coming in on the power lines. The same with TVs and other home entertainment gear.

Over the years I have lost more cordless phones and answering machines than I can count. I unplug the laptop and the main computer, modem and router, and pull the line from the cable jack whenever I am away from home, and overnight or immediately, whenever there is even a slight chance of thunderstorms.  I also pull the big switch in the shack and ground all the antennas.

The power lines here seem to attract lightning.  We would get destructive surges all the time, but rarely ever at work which was only 8 miles from here. We also get frequent power outages while outdoor lights are still visible in surrounding communities.

As a safety precaution, I run the TV, stereo and associated stuff through an Iso-Top isolation transformer, and adjust the tap for about 115 volts. My theory is that the transformer will saturate on peaks and limit the amplitude of power surges, without crapping out the way cheap surge protectors do.

Unlike devices that run on small wall-warts, bigger items like TVs and DVD players do draw substantial power when "off".  Something has to stay powered up to run the stand-by circuitry that keeps them responsive to the power on/off function on the remote.

[W4NEQ]

Dave,

You experiment illustrates the fallacy of much of the energy-savings edicts coming from the green Nazis.  

I'm all for genuine power savings, but too often the non-technical policy makers push misguided approaches - focusing way too much on reducing negligible loads while ignoring much larger inefficiencies.  OR saving pennies in electricity usage while compromising their primary business mission.   I recently spoke with an operator of a 1 kw am station in a reasonable market who was operating at 250 watts to save money on the power bill - having been persuaded by the energy Nazis.   When the math demonstrated he was saving about $1.50 per day, common sense prevailed.

At my former employer's buildings, there was a big push to darken unused areas when not constantly used, while running central a/c simultaneously with electric heat.

The push toward reducing incandescent lighting offers some genuine power savings, but the screw-in florescent replacements have reduced life in applications where, obeying the Nazis instructions, are switched on / off many times per day - and worsen disposal issues while costing much more than filament lamps.  LED fixtures will probably be the ultimate answer - eventually.

As far as wall-warts go, as previously advised, if it runs noticeably hot while idle, it MIGHT warrant unplugging.

Chris
 

    

[KB2WIG]

I'm more inclined to pull the plug, warts and all. To me, they are little thermite devices, waiting to go off.

I did get to catch my Mr Coffee michine in Charnoble mode. 1.2 kW of power on a 20 Ampere line. Fun times.


klc

[DMOD]

I recently spoke with an operator of a 1 kw am station in a reasonable market who was operating at 250 watts to save money on the power bill

He had a waiver from the FCC to do that?

Phil - AC0OB

[W4NEQ]

I recently spoke with an operator of a 1 kw am station in a reasonable market who was operating at 250 watts to save money on the power bill

He had a waiver from the FCC to do that?

Phil - AC0OB

No.  I reminded him of than minor fact as well.

[WQ9E]

In addition to Don's comments on lightning some of these little devices continue to create RF garbage even with no load.  My daughter has a Color Nook reader and when she left it plugged in (without the Nook attached) near my Grundig Sattelit 800 (that doubles as a kitchen radio) 780 AM out of Chicago was wiped out unless I hooked up my 80 meter loop to its external antenna port.    The crud falls off with frequency but it was still very evident on 3885.

Many of the older transformer type wall warts depended upon the transformer primary to act as a fuse if something went wrong, I have no idea how the modern switching type adapters are set up for protection but it seems like a good idea to keep them out of the wall when not in use, especially when you are away.

[W1RKW]

some of the wall warts are SMPSs and create RFI as opposed to simple linear PSs. Off they go when their done doing their duty.  My router uses a SMPS wall wart.  I had to put it in a metal box and ground the box to shut the thing up.  It produce noise beyond the 10m band. Also put it on a timer to shut it off during off hours. The combo uses 23watts.

Also, as someone mentioned, they're ticking time bombs waiting to go off.  Unplug them if not needed, no fires.

[Opcom]

Dave,

At my former employer's buildings, there was a big push to darken unused areas when not constantly used, while running central a/c simultaneously with electric heat.

Chris
 

If 300 wall warts each use 2 watts, that is a major waste. If they are ON for the 16 hours each day no one is using them, it is 9600 watt hours, and that could light sixteen of the office luminaires having a solid state ballast for one 8 hour day.

Not to mention the possible waste of 300 laptop power bricks being left on all the time. Who knows how much waste that would be.

It's not so much that at home we waste 10 watts or 30 watts on these things. All the neighbors do it too, 24x7, and it adds up.

My employer goes to great lengths to eliminate waste and has also cut back on major wasteful and polluting things like air conditioning to a great extent in order to reduce the carbon footprint. It is sometimes 76 degrees in my cubicle. I can only say that I agree with our goals.

[ke7trp]

Both of my USB cell chargers put hash on the ham bands when the phone is unplugged. The switcher goes high and puts a nasty signal on 10,12 and 15.  As a result, I just unplug them.   

An actual wall wart can and will pull power though.  My yaesu HT charger and my Cordless Drill charger both have heat in them just sitting there with no load.  Those are now on a power strip and just get turned off.

So power usage?  Minimal.  Potential, noise makers?  High. 



C

[k4kyv]

Many places do like our local school system, which has about two dozen individual campuses, but the HVAC in all buildings are centrally controlled, allegedly "to save energy". Problem is, they overcompensate. In hot weather the thermostat runs at 68°.  In winter they set it to about 78°.  When I used to work there, it was not unusual to see rooms with the outside door propped open with a chair or an old book -  in winter to cool it off, and in hot weather to warm it up.  Otherwise, you sometimes needed a sweater indoors when it was 90° outside, and it would be uncomfortable to wear more than a tee-shirt on days when outside temperature was below 40°.

I never understood why they couldn't just keep it at about 74° year-round.

[Opcom]

My favorite, beginning around this time of year, is restaurants that keep their dining area cold enough to hang meat. The hired help is keeping cool while the poor customers are freezing. A clear case of the inmates running the prison.

They need a manger with "management by objective" to reduce utility cost x% year over year linked to compensation. That's how they grind it down to the bone in the big world.