On 04/11/17 14:50, tim... wrote:
I have (elsewhere) previous been recommended to buy a power bank to uses
as an emergency back up for my portable devices.

Which, because I have a candy bar phone with a standby time of 3 weeks,
means my tablet and camera.

I was in a shop today, saw one on sale with "for smartphones and
tablets" at a reasonable price and bought it

but after I looked at the back it said output 5V 1A.


The key figure is the capacity, measured in milliamperehours (mAh),
typically on the cheap power banks 1200mAh. It will be stated on the
packaging somewhere.

The 5V is the standard voltage for USB and 1A is the maximum rate at
which it can charge your phone. So at 2A the phone will be charged in
half the time it will take at 1A (assuming the phone can take it which I
doubt).

The cheap power banks seldom have the claimed capacity but, for
emergency top ups, does it matter that the phone will only be charged to
half its maximum?

Another Dave

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