This is a newbie question. While travelling, I need to recharge my Galaxy Nexus and my digital camera, both of which are meant to be charged through a micro-USB port, ie. 0,5A.

To reduce charging time, I have an 1A AC adaptor but it only has a single USB port.

Google shows a number of two-port AC adaptors:

  • one port is 1A, the other is 2,1A (it looks like Apple devices expect 2,1A)
  • this one delivers 2A when using a single port, but 1A when using both ports

In case I only need to charge a single device, is it safe to have it fed 2 or 2,1A? I read that a device only uses the intensity it needs, but will it fry if it's fed too much intensity?

Thank you.

marked as duplicate by geffchang, Izzy, Zuul, ce4, onik Nov 20 '13 at 7:24

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Yes, it is fine to charge a device with a higher current charger.

You can think of current like the device pulling rather than the charger pushing. The device will only take as much current as it wants regardless of how much the charger is capable of supplying.

  • Thanks for the confirmation. Is there some waste (heat?) when using a charger that outputs more amps than a device needs? – Gulbahar Nov 19 '13 at 20:53
  • There's always waste heat (no transformer or converter is 100% efficient), but a oversized charger doesn't increase the waste. The charger will only supply as much current as the device pulls, and the charger in turn will only pull as much current from the wall as it needs to supply that current to the device. – Compro01 Nov 19 '13 at 20:55

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