modern vs old wall wart (aka cell phone, ipod, etc. chargers)

Daox · 07-03-12, 12:56 PM

This past week I took some time to do some testing with the newfangled wall warts that come with all our modern gizmos (cell phones, tablets, i-pods, etc.) to charge them up. I checked the house and saw that I typically have 5 of these things plugged in 24/7/365. Now, I know with old brick type wall warts, those would be pulling at least a few watts constantly and acting as constant small heaters (you can feel that they're warm). However, I've been told that these new 'switching type' wall warts are much better on power.

So, I decided to test how much better these new devices were. I grabbed all 5 of the wall warts that I have plugged in all the time and plugged them into a power strip. I then plugged that power strip into my kill a watt and plugged that into the wall. With the old type wall warts I'd expect to see 10-20W being pulled. However, to my pleasant surprised my kill a watt registered absolutely nothing, 0W. That is all 5 of them running together. In the past, I had been a stickler about unplugging these things, but thanks to the wonders of new technology this is no longer needed.

Now, I actually lied, I do have a 6th wall wart out in the garage powering my dog's invisible fence. I believe I have yet to test that out to see what king of power it is using. However, I believe I should be able to convert that over to a switching type power supply due to the overabundance of extra wall warts that I do have laying about the house from old devices I no longer use. I'll make sure to post back with the findings there.

Anyway, how do you know if your power supply is a new or old type? Well, really the most simple way to check it out is to just touch the thing. If its warm, its the old type that wastes energy. If its the new type it won't be warm. The new type also tend to be smaller where as the old type are very square/rectangular in shape.

New type:

Old type:

I'll probably be writing a blog post on this in the near future. If you guys think I missed anything or should add some additional info I'm all ears.

strider3700 · 07-03-12, 01:27 PM

I noticed the new ones are really good a few years ago, what I haven't been able to figure out is if there is a limit to the wattage on the new ones. I've only tested things like you did, cell phone, ipod,.. all very low wattage devices.

Piwoslaw · 07-03-12, 02:03 PM

I'd like to see how efficient they are at actually charging something. How about a test: Charge the same device with an old and a new wall wart, record watt-hours consumed in both cases. You might need to do a few (5-15 with each) tries and average them, since each time the batteries may be discharged to a different level.

Daox · 07-03-12, 02:19 PM

That would be interesting. I might be able to do something like that... I should be able to measure current draw with a multi-meter and just plug say a light into an old type, then into the new type.

MN Renovator · 07-03-12, 02:44 PM

Regarding efficiency while powering a load, it depends on the unit, some have an 'Efficiency level' with a roman numeral after it which rates what the efficiency is at under load.

Looking at some power supply spreadsheets on the Meanwell site, it looks like high 80's and into the low 90's is probably fairly normal efficiencies to expect. Some power gets lost in the capacitors, some to switching losses, etc on the way to DC.

Not sure how that compares to old linear power supplies, I just looked around my house at all the power supplies I use and can't find anything that's not a switch-mode supply.

MaxHedrm · 07-04-12, 01:02 PM

Uh, why would you waste the money on a switching power supply for something like your dog fence (or an alarm system, or clock) that is always on? A higher efficiency one, perhaps, but the switching would buy you nothing.

Daox · 07-04-12, 02:14 PM

Who said anything about wasting money?

Quote:

However, I believe I should be able to convert that over to a switching type power supply due to the overabundance of extra wall warts that I do have laying about the house from old devices I no longer use.

I would disagree that switching to a new power supply will save me nothing, especially based on what MN Renovator has posted.

MaxHedrm · 07-04-12, 02:39 PM

Well, true, and I was speaking in general, not just for your fence, but for people that would go out & replace everything. It seems that unless it's a 20 year old power supply your gains will be minimal if at all. And if it's a 20 year old power supply, I would be amazed it still worked anyway. :-D

Clev · 07-04-12, 03:37 PM

Depends on the power supply. I had an old set of Boston Acoustics computer speakers with a massive "old" power supply. It drew 40W continuously, whether it was plugged into speakers or not.

In that case, I had other sets of computer speakers laying around, so I just gave those away, but I could see checking online to see if I could replace that with a more efficient switchmode.

Ryland · 07-05-12, 01:47 AM

I did the same test a few years back only I did it with my Fluke multi meter set to amps and found it drew a fraction of an amp, figured leaving it plugged in would cost me just under 2 cents per year... yep.

As far as losses when they are doing work like charging, I've heard that they can be as good as 98% efficient and as low as 92%, mine don't tend to even feel warm after they have been charging something for a while.

07-03-12, 12:56 PM	#1
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	modern vs old wall wart (aka cell phone, ipod, etc. chargers) This past week I took some time to do some testing with the newfangled wall warts that come with all our modern gizmos (cell phones, tablets, i-pods, etc.) to charge them up. I checked the house and saw that I typically have 5 of these things plugged in 24/7/365. Now, I know with old brick type wall warts, those would be pulling at least a few watts constantly and acting as constant small heaters (you can feel that they're warm). However, I've been told that these new 'switching type' wall warts are much better on power. So, I decided to test how much better these new devices were. I grabbed all 5 of the wall warts that I have plugged in all the time and plugged them into a power strip. I then plugged that power strip into my kill a watt and plugged that into the wall. With the old type wall warts I'd expect to see 10-20W being pulled. However, to my pleasant surprised my kill a watt registered absolutely nothing, 0W. That is all 5 of them running together. In the past, I had been a stickler about unplugging these things, but thanks to the wonders of new technology this is no longer needed. Now, I actually lied, I do have a 6th wall wart out in the garage powering my dog's invisible fence. I believe I have yet to test that out to see what king of power it is using. However, I believe I should be able to convert that over to a switching type power supply due to the overabundance of extra wall warts that I do have laying about the house from old devices I no longer use. I'll make sure to post back with the findings there. Anyway, how do you know if your power supply is a new or old type? Well, really the most simple way to check it out is to just touch the thing. If its warm, its the old type that wastes energy. If its the new type it won't be warm. The new type also tend to be smaller where as the old type are very square/rectangular in shape. New type: Old type: I'll probably be writing a blog post on this in the near future. If you guys think I missed anything or should add some additional info I'm all ears. Attached Thumbnails __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by Daox; 07-03-12 at 01:03 PM..

07-03-12, 02:03 PM	#3
Piwoslaw Super Moderator Join Date: May 2009 Location: Warsaw, Poland Posts: 961 Thanks: 188 Thanked 110 Times in 86 Posts	I'd like to see how efficient they are at actually charging something. How about a test: Charge the same device with an old and a new wall wart, record watt-hours consumed in both cases. You might need to do a few (5-15 with each) tries and average them, since each time the batteries may be discharged to a different level. __________________ Ecorenovation - the bottomless piggy bank that tries to tame the energy hog.

07-03-12, 02:19 PM	#4
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	That would be interesting. I might be able to do something like that... I should be able to measure current draw with a multi-meter and just plug say a light into an old type, then into the new type. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

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07-03-12, 01:27 PM	#2
strider3700 Master EcoRenovator Join Date: Dec 2008 Location: Vancouver Island BC Posts: 745 Thanks: 23 Thanked 37 Times in 30 Posts	I noticed the new ones are really good a few years ago, what I haven't been able to figure out is if there is a limit to the wattage on the new ones. I've only tested things like you did, cell phone, ipod,.. all very low wattage devices.

07-03-12, 02:44 PM	#5
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	Regarding efficiency while powering a load, it depends on the unit, some have an 'Efficiency level' with a roman numeral after it which rates what the efficiency is at under load. Looking at some power supply spreadsheets on the Meanwell site, it looks like high 80's and into the low 90's is probably fairly normal efficiencies to expect. Some power gets lost in the capacitors, some to switching losses, etc on the way to DC. Not sure how that compares to old linear power supplies, I just looked around my house at all the power supplies I use and can't find anything that's not a switch-mode supply.

07-04-12, 01:02 PM	#6
MaxHedrm Lurking Renovator Join Date: Apr 2010 Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts	Uh, why would you waste the money on a switching power supply for something like your dog fence (or an alarm system, or clock) that is always on? A higher efficiency one, perhaps, but the switching would buy you nothing.

07-04-12, 02:39 PM	#8
MaxHedrm Lurking Renovator Join Date: Apr 2010 Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts	Well, true, and I was speaking in general, not just for your fence, but for people that would go out & replace everything. It seems that unless it's a 20 year old power supply your gains will be minimal if at all. And if it's a 20 year old power supply, I would be amazed it still worked anyway. :-D

07-04-12, 03:37 PM	#9
Clev Wannabe greenie Join Date: Sep 2008 Location: Crestline, CA Posts: 74 Thanks: 1 Thanked 1 Time in 1 Post	Depends on the power supply. I had an old set of Boston Acoustics computer speakers with a massive "old" power supply. It drew 40W continuously, whether it was plugged into speakers or not. In that case, I had other sets of computer speakers laying around, so I just gave those away, but I could see checking online to see if I could replace that with a more efficient switchmode.

07-05-12, 01:47 AM	#10
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	I did the same test a few years back only I did it with my Fluke multi meter set to amps and found it drew a fraction of an amp, figured leaving it plugged in would cost me just under 2 cents per year... yep. As far as losses when they are doing work like charging, I've heard that they can be as good as 98% efficient and as low as 92%, mine don't tend to even feel warm after they have been charging something for a while.