I know you can use a 9 volt battery to power an arduino without too much trouble, but for my project im going to need some more amps, rather then the 150mA i get from the 9volt. I have a 9.6 volt, 1600 mAh NiMH battery. Could i connect that just as easy as a 9 volt? Or do i need a regulator or something...
this is the battery: http://www.radioshack.com/product/index.jsp?productId=3999878
(I think thats a new record. Got my question answered twice in 5 minutes. This is a great forum :D)
However the quick answers may not give the complete picture. While you can of course wire any battery of less then say 12-15 volts to the Arduino's external power connector, how much current you can draw from it has limits. What is the maximum current you will be trying to draw from the battery?
You stated that 150ma is not enough, but not what your loads (internal +5vdc regulator and Vin pin for external power for external loads if used) will require. There is a series polarity protection diode used with the external power connector that I think has a one amp continuous rating.
So a larger battery with a higher MAH rating will always give a longer duration then a smaller rated battery, your actual current consumption is also an initial specification that should be determined to see if a specific battery is going to best meet your needs.
Are you drawing the extra power directly from the battery or through the arduino's wiring?
If you go direct than there is no problem at all, just make sure the cable you use is rated for the ampage. If your drawing it through the board, be careful, the circuit traces were not designed to carry large currents. They will carry a reasonable amount, but are not designed for large loads. If your after a 5V output, that is limited by the onboard regulator, if you need more current at 5V then you will need a more powerful 5v regulator.
Well thats why I was asking. Pretty much what I have right now is the power from the arduino going to a breadboard, then powering 2 servos and 2 sensors. But I want to add 2 more servos, ultrasonic and 2 IR rangefinders. So will that be drawing too much power, or will it be ok? Or do I hav to get a seperate battery for the servos, and just use the 9volt to power the arduino and sensors.
Something it seemed from your question that you didn't yet know....
The "heart" of the Arduino board runs at 5v or 3.3v, depending on what Arduino you have. But the board has a regulator circuit on it, to create the necessary regulated voltage from the external voltage which you supply from battery or wall-wart.
150 mA running, 8 mA idle. i dont know about the sensors, its just a photo diode with a resistor on it. a 6400 resistor.