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Can chargers damage my phone?

  1. Mar 10, 2012 #1


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    My phone (LG 900something) takes several hours to charge when plugged into my USB port (with a cable that came with the phone). But it only takes an hour to charge using a 3rd party charger plugged into the cig lighter of my car (charger is meant for phones, but its got, like, 10 tips).

    I can presume the difference is that USB is 5V whereas auto is 12V.

    My question is: can the 3rd party (faster) charger damage my phone or shorten my battery life?
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  3. Mar 10, 2012 #2

    I like Serena

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    Short answer, yes, a 3rd party charger that has not been specifically designed for your phone can damage the battery and/or shorten its life.

    You may be interested in this section of the wiki article (if you haven't already read it, since the whole article is pretty interesting):
    which also refers to another wiki article about USB power and standardization.

    Myself, I would use a 3rd party charger only if it is made by or recommended by the manufacturer of my phone.
  4. Mar 10, 2012 #3


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    It didn't come with an electric charger? You can order a replacement electric phone charger.
  5. Mar 10, 2012 #4


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    It came with a USB cable and a wall wart (i.e. power pack) that plugs into the cable.

    But I find it very useful and convenient and even necessary to be able to charge my phone in the car.
  6. Mar 10, 2012 #5


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    The charging circuit will be in the phone, not in the "charger", especially with modern battery technology.

    The important thing is that the charger voltage is within the specification of what the phone can handle. A cheap "12V" car charger may produce 14 or 15V when the car engine is running.

    A "base level specification" USB port will supply 0.5A max current, and that will take several hours to fully charge a phone. On the other hand "battery charging" USB ports can provide up to 5A -the safe current is limited by the physical design of the USB connectors, not by the electronics.

    A charging time of about 1 hour seems quite reasonable without reducing the charge holding capacity of the number of charge-discharge cycles, IMO. The old recommendations like "slow-charge Ni-Cd batteries over 20 hours to extend their lives" aren't relevant to modern battery systems.

    EDIT: Check how long it takes to charge from the wall wart. If that is about the same as from your car charger, you probably don't have anything to worry about.
    Last edited: Mar 10, 2012
  7. Mar 10, 2012 #6


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    How about getting a real LG automotive charger? I have bought 3 LG phones over the last few years for myself, father and wife, and they all came with 12V automotive chargers as well as wall-warts. You should be able to get an LG 12V adapter for your phone quite inexpensively.
  8. Mar 10, 2012 #7


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    This auto charger has a USB connection. i.e. it is two pieces - one plugs into the cig lighter and exposes a female USB port, then a separate piece has a male USB with its dozen splitters.

    Not sure if that helps matters.

    I would, but my wife does the same thing with her Blackberry. The charger we have has multiple outlets for simultaneous charging. To get a LG-dedicated charger would squeeze her out.
  9. Mar 10, 2012 #8


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    Too bad. My wife's Subaru Forester and my Honda Ridgeline pickup have more 12V charging sockets than we'd ever need. She's even got a charging socket in the cargo area of that rig.
  10. Mar 10, 2012 #9


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    I'd concur with the above - I'd expect a 1 hr recharge to represent an input voltage that is comfortably within parameters.

    It is the computer USB that is likely to be low on the input volts - there will likely be a diode in the circuit to prevent reverse polarisation, so scrubbing a half volt or so off of 5V, which is probably pulled a bit low already because it is only a 300mA output, then you'd probably end up with lowish 4V to charge a nominal 3.7V battery, whereas I'd guess (don't hold me to it, but comparing it with other proprietary rechargers) the chargers you get with phones are 'nominally' 5V but I'd expect they give out a tad more. Your car charger probably gives a little more still, but you only need to go up a half a volt or so and you'll be increasing your recharge rate by a noticeable factor over a USB-voltage charger.

    So long as the battery doesn't get physically hot ('warm' is OK) then it should be just fine.

    Just to mention, I've had problems with one particular smart phone in the past which just will not charge at all from a computer USB but will charge fine from an 'adapter' with a USB output. Both measure nominally correct voltages without a load on them, so I guess the adapter can just put out better current without folding back on the voltage.
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