On 08/10/2014 18:12, Bod wrote:
On 08/10/2014 15:56, Brian Gaff wrote:

Brian, any device will only draw the current it needs, as far as I know.

That isn't necessarily true. Any well designed device will only take
what it needs and then feather the charge current to zero.

A badly designed device will keep taking current until either it
overheats and vents the battery or the battery catches fire depending on
the precise battery technology being used.

Polite devices are supposed to ask the OS to enable high current mode
but some just grab without asking and that can cause trouble sometimes.

Well, I don't like them as they are not always current limited. I
don't like
usb wall warts either.
I know a person who trashed their mp3 player charging this way, over
cooked
the battery.
Brian

Most are short circuit protected and will give very little more than
their nominal maximum output. The problem lies with devices that assume
that the maximum output is 1A (or worse 0.5A) when there are now 2A
units about. Naive older devices can get cooked this way.

I already have more than enough wallwart ones and seldom need more than
two in use at a time. I can't see the point in having one in the wall.

At least now they all give the same voltage and a common connector. The
previous mobile phone and laptop charger wars led to a proliferation of
random voltages, currents and ever more weird connectors.

I doubt that USB charge currents will go up too much more as the present
value is close to the limits for the connectors to be reliable.

--
Regards,
Martin Brown