# Do Cell Phone Chargers Still Draw Power if Left Plugged In?

**URL:** <https://boards.straightdope.com/t/do-cell-phone-chargers-still-draw-power-if-left-plugged-in/502657>\
**Category:** Factual Questions\
**Created:** [July 11, 2009, 6:29am UTC](https://boards.straightdope.com/t/do-cell-phone-chargers-still-draw-power-if-left-plugged-in/502657 "2009-07-11T06:29:18Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\
**Post date:** [July 11, 2009, 6:29am UTC](https://boards.straightdope.com/t/do-cell-phone-chargers-still-draw-power-if-left-plugged-in/502657/1 "2009-07-11T06:29:18Z")

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[This commercial](http://www.youtube.com/watch?v=oax0cZPY3ak) (50 seconds in) states that chargers still draw power and waste energy, if you leave it plugged in the outlet, although your cell is not attached.

C’mon, really?

Why/How could that be? My cell charger is for my iPhone (Wall plug to USB), and I feel no heat whatsoever when the phone is disconnected.

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**Author:** ![Myrrajh](https://avatars.discourse-cdn.com/v4/letter/m/87869e/32.png) [@Myrrajh](https://boards.straightdope.com/u/Myrrajh)\
**Post date:** [July 11, 2009, 7:31am UTC](https://boards.straightdope.com/t/do-cell-phone-chargers-still-draw-power-if-left-plugged-in/502657/2 "2009-07-11T07:31:38Z")

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I can’t find a cite, but I read or saw something that debunked that claim. Someone had a voltmeter or something on a phone charger that was plugged in but not being used to charge a phone, and it was drawing zero power.

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**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\
**Post date:** [July 11, 2009, 10:15am UTC](https://boards.straightdope.com/t/do-cell-phone-chargers-still-draw-power-if-left-plugged-in/502657/3 "2009-07-11T10:15:58Z")

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Chargers that are plugged in do use some energy even when not charging. It’s not doing nothing. It’s taking AC power and converting it to DC and regulating it to the proper DC output value. Even when there is no charging load attached to that output voltage, it still takes some current for the voltage regulators and such to do their thing.

The amount of current they draw when unloaded is pretty small though.

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**Author:** ![jacquilynne](https://avatars.discourse-cdn.com/v4/letter/j/67e7ee/32.png) [@jacquilynne](https://boards.straightdope.com/u/jacquilynne)\
**Post date:** [July 11, 2009, 1:24pm UTC](https://boards.straightdope.com/t/do-cell-phone-chargers-still-draw-power-if-left-plugged-in/502657/4 "2009-07-11T13:24:11Z")

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Well, mine has a little red light on it, so it definitely draws power when it’s plugged in but without a phone connected.

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**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\
**Post date:** [July 11, 2009, 1:44pm UTC](https://boards.straightdope.com/t/do-cell-phone-chargers-still-draw-power-if-left-plugged-in/502657/5 "2009-07-11T13:44:08Z")

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We just did this: [Leaving cell phone rechargers ibn the wall - Factual Questions - Straight Dope Message Board](http://boards.straightdope.com/sdmb/showthread.php?t=523370)