Arduino and shield high current supply help?

Other Hardware Motors, Mechanics, Power and CNC
1

I've been meaning to get a mains adapter to power my Arduino from the mains for a while now, as I've found out the hard way that my 18V one didn't really work. Still waiting for the replacement Mega 2560 :o . While I know now to choose between a 9V and 12V supply to plug in to the Arduino, I am using a SIM900 shield with it, and its datasheet says it may have current peaks of up to 2A and therefore a 2A capable power supply is needed. I do not wish to connect a 5V 2A seperately to the shield so as to avoid extra cables, and do wish to power it from the Arduino, which has worked off 6 AA batteries (9V) with no problems.

Therefore, is it possible to power an Arduino Uno or Arduino Mega 2560 off a 9/12V 2/5A (5A so as to allow for other devices attached to the Arduino such as an LCD) and what would be optimal.

Thank you in advance for your help!

Ciarán

2

Can you give a link to your shield ?
I would like the check the schematic and maximum current.
This one is only maximum 450mA : http://www.seeedstudio.com/wiki/GPRS_Shield_V1.0

3

is it possible to power an Arduino Uno or Arduino Mega 2560 off a 9/12V 2/5A (5A so as to allow for other devices attached to the Arduino such as an LCD)

The internal regulator on the Arduino can only handle about 500mA or so of current ( depending on the exact input voltage ) so anything powered from the arduino must not exceed this current. You can only draw 5A, if the power supply can provide it and if you wire it separately from the arduino's supply.