Standby power annual cost calculation

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M_BROWNLOW

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I'm interested in calculating the $$$ cost associated with the standby power (aka vampire power, aka phantom load) of my cell phone charger over the course of one year (365 days).
In this scenario the charger would always be connected to 120V but the cell phone never plugged into it.

The calculation seems straightforward but I have no one to check my work so I'd appreciate a review by one (or more) of you folks.

Here is the data:

Standby power: 3W
Utility rate: $0.1067 per KWH

My calculation yields $2.81 for the year.

Regards,

Matt
 
It (your charger, what many will classify as a 'wall wart') most likely draws more power when your phone is plugged in and charging than when it's just sitting there with no load. Transformers are kinda funny that way..... they draw power even with no load. The 3 watts is likely the maximum output of the thing, not any kind of power draw on the primary side. So your calculations need to take into consideration the load varaibles.
 
M_BROWNLOW said:
Here is the data:

Standby power: 3W
Click to expand...

Where did you get this info? I have 2 Nokia's that say 4.8va and 5va. Call me kookie but I unplug the when not in use.
 
Thank you for the replies so far.

480sparky said:
It (your charger, what many will classify as a 'wall wart') most likely draws more power when your phone is plugged in and charging than when it's just sitting there with no load. Transformers are kinda funny that way..... they draw power even with no load. The 3 watts is likely the maximum output of the thing, not any kind of power draw on the primary side. So your calculations need to take into consideration the load varaibles.
Click to expand...

3 watts is the standby power of the charger when plugged into 120 V without the cell phone connected. I'm interested in simulating this scenario for a continuous 365 days and determining the $$$ cost.


chris kennedy said:
m_brownlow said:
Here is the data:

Standby power: 3W
Click to expand...

Where did you get this info? I have 2 Nokia's that say 4.8va and 5va. Call me kookie but I unplug the when not in use.
Click to expand...

I used an energy meter.

--------------------------------------------------------------------------

So, how is my math on the $2.81 for the year?

Regards,

Matt
 
M_BROWNLOW said:
I used an energy meter.
Click to expand...

I looked at the data on the warts.

Interesting question, but in the end, unplug them when not in use.

And yes, the math looks good to me.
 
081019-1825 EST

M_BROWNLOW:

Yes your calculation is correct.

I measured the input current, unloaded, at 33 MA to a CUI Inc. AC Adapter rated at 120 V 60 Hz 10 W input, rated DC output of 9 V 500 MA.

Thus, the unloaded input power is less than 120*0.033 = 3.88 VA.

.
 
chris kennedy said:
I looked at the data on the warts.

Interesting question, but in the end, unplug them when not in use.

And yes, the math looks good to me.
Click to expand...

Part of my current role as an Energy Advisor is to encourage clients to do just that. :smile:
I wanted a $$$ figure to go with my energy meter demonstration to make the point sink in.
Thanks (gar too) for confirmation on the $2.81.

Regards,

Matt
 
wireguru said:
ill pay $0.20/mo for the privilige of not having the hassle of plugging and unplugging my charger....
Click to expand...

I recently encountered this entertainment setup, not uncommon by any means...

Flatscreen tv
DVD player
Satellite tv receiver
Playstation
Stereo

Total standy power of all appliances when OFF...61 W.

So if one were to imagine in the course of one year that none of these devices were actually turned on, instead they just sat there plugged in but turned off, it would be the equivalent of having left a 60 W lightbulb on 24 hrs/day for that year.
Pricetag $57.14 for nothing.

Point is it all adds up. (Perhaps it could pay for a month of your cell phone service wireguru ;) )

Regards,

Matt
 
M_BROWNLOW said:
Flatscreen tv
DVD player
Satellite tv receiver
Playstation
Stereo

Total standy power of all appliances when OFF...61 W.

Pricetag $57.14 for nothing.
Click to expand...
Not having to go through all of the volatile settings' menus is worth it for me.
 
081019-1945 EST

M_BROWNLOW:

I have now connected a wattmeter to the above mention CUI power supply. Unloaded the power input was:
90 VAC slightly less than 1 W, estimate 0.9 W. The meter is 75 W full scale.
110 VAC 1.0 W
120 VAC maybe 1.2 W.

Next test was on my cellphone charger. This is a switching regulator type.
Under no load the power was probably about 0.1 W.
Charging a partially discharged battery was about 2 W.

I see no reason to unplug a cellphone charger. Chargers that are rated 90 to 240 V input will be switching regulator types.

Relative to the other always on when off appliances the fault is with the manufacturers and the buyers. There is no problem to use CMOS memory with battery backup to maintain a real time clock and all prameters. To some extent we have done this since 1975 when static CMOS memory first became available.

Dallas Semiconductor makes real time clocks with a built in battery that will maintain operation for 10 years with no external power. These probably have been around since 1985 to 1990. My memory is foggy as to when we first used them.

.
 
There are new federal standards for appliance standby power that will come into play in the next two years or so. My son worked as a co-op engineer for one of the major appliance manufacturers this past summer and that was what he was working on. They were trying to get the standby power to less than one watt.
 
don_resqcapt19 said:
There are new federal standards for appliance standby power that will come into play in the next two years or so. My son worked as a co-op engineer for one of the major appliance manufacturers this past summer and that was what he was working on. They were trying to get the standby power to less than one watt.
Click to expand...

Canada has also begun implementing the same '1-Watt Initiative' your son was working on.
Congrats to him on his work.

http://www.nrcan-rncan.gc.ca/media/newcom/2007/200767-eng.php

Matt
 
M_BROWNLOW said:
I recently encountered this entertainment setup, not uncommon by any means...

Flatscreen tv
DVD player
Satellite tv receiver
Playstation
Stereo

Total standy power of all appliances when OFF...61 W.

So if one were to imagine in the course of one year that none of these devices were actually turned on, instead they just sat there plugged in but turned off, it would be the equivalent of having left a 60 W lightbulb on 24 hrs/day for that year.
Pricetag $57.14 for nothing.

Point is it all adds up. (Perhaps it could pay for a month of your cell phone service wireguru ;) )

Regards,

Matt
Click to expand...

i bet a good portion of that was the sat receiver since its powering the LNB on the dish......
 
081020-0649 EST

No appliance needs to require any power when off. The only exception would be remote controlled systems that require remote on control. In this case it probably can be done in the milliwatt range.

.
 
[Standby power: 3W
Utility rate: $0.1067 per KWH

My calculation yields $2.81 for the year.

Where are you buying power at 11 cents/KWH???? we are paying close to 20 cents.:-?
 
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