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Powering an Arduino with 9V batteries? Answered

I'm looking at powering my Arduino with 2 9V batteries wired in parallel (2 is optional, but if you think a single 9V battery can power an arduino + 16 LEDs simultaneously for >3 hours, let me know).

I have a few different options for linear regulators. LM350 (3A), C33275 (300mA), LM7805 (1A, 5V) - I'm guessing I should use the LM7805 because it's fixed at 5 but I'm not sure.

I'm not too electronics-savvy so as much help as you're patient enough to give would really be appreciated!


WHICH Arduino - there are dozens ! An Uno will run on 9V directly.

An Atmega328 is just a chip. Do you HAVE an Arduino board, or a chip programmed with a bootloader ?

It's a board called Diavolino, it has space for a voltage regulator that I'm not currently using because the one I have doesn't fit in the holes (I'll make it later as necessary)

You should be able to squeeze a 7805 into that, but it will get quite warm with 160mA x 4V dissipated in it.

My 7805 is in the following form ( http://bit.ly/17mcyb9 ) So I can always screw a heatsink on if necessary. Back to my original question, would the 9V batteries be enough?

An Alkaline 9V battery has around 500mAHr capacity. Two, all being well, 1000mAHr. Taking your estimated consumption from my numbers - 160mA, then you'll get roughly 1000/160 hours from them. More than three.