Mains Charge > USB Charge


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  1. Fleming

    Fleming Member This Topic's Starter

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    I have found that charging my HTC Hero from the wall with the USB adapter charges faster than charging from the USB plugged into the pc.
    This may sound like common sense, but there's more to it...

    Some iPhone users have noticed that the charge from their phone when charged from the mains lasts longer than the charge from the PC via USB. Some sites claim that phone batteries can be 'overcharged' by charging from the mains, and that USB charging doesn't do this.

    I havn't had my phone long enough to test the 'overcharging' theory, but I was wondering if anyone had any information about these different methods of charging.
     

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  2. kwiksand

    kwiksand New Member

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    I strongly doubt there's any overcharging going on, probably pure co-incidence that the user perceived their iPhone discharging quicker. On the other hand, there's no wonder these phones charge quicker off mains power than from Computer power as the power available to charge from a computer USB port is many, many times less that via mains.
     
  3. Russ Dill

    Russ Dill Well-Known Member

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    Speaking of charging slower via USB (500mA), has anyone seen any pigtail cables for microusb to allow charging from two USB ports? I've seen this for miniusb, but not for microusb.
     
  4. Andronix

    Andronix Well-Known Member

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  5. jimbobmcginty

    jimbobmcginty Well-Known Member

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    The wall charger gives out 1A (1000mA) against USB's 500mA maximum. You may also find that your computer doesn't give the full 500mA (which is wank). That's why other posters are suggesting the double USB cable thing, to combine the currents from two ports.

    For a great explanation of all things Li-ion and other battery technologies, have a look at:

    Charging lithium-ion batteries

    It should dispel many myths! Having said that, in the past I too have had the perception of a USB charge not lasting as long as a wall charge. No proper testing done, could simply be imagination because I know USB only kicks out half an amp (and then ignore all logical thinking I might do).
     
  6. Andronix

    Andronix Well-Known Member

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    great link, thanks.

    " ...high current charge tends to push the voltage up and forces it into the voltage limit prematurely..."

    -> meaning lower current from USB host is better, and I noticed it already.

    If you use wall charge, you can notice that battery drops to 97% almost few minutes after unplugging charger, while it stays much longer at 99% if you use slower USB charging.
     
  7. jimbobmcginty

    jimbobmcginty Well-Known Member

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    Somewhere on that site it explains that more recent chargers charge at full pelt up to 70% or so, and then switch into trickle mode to get the maximum into the battery.

    It also says that you should once charged you should unplug the device (mp3 player/phone/ps3 control) etc because permanent trickle charging can reduce the life of the battery. Made me think about my laptop, that is usually plugged in.... but then I only ever get 90 minutes without a cable ;D
     

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