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Topic: 6V Battery Power Arduino (Read 4 times) previous topic - next topic

rfmaster93

Hey all,

I was doing some looking around and didn't see if this would be kosher or not.

I have a power hungry sensor, and an Xbee connected to an arduino, and I need a nice big battery to power it for a long time. Not sure why, but the 9 volts i'm connecting to it aren't doing the job. I get around 20 minutes or sometimes less out of them before the Xbee starts failing. I was thinking of hooking up one of those big 6 volt battery's to give me a nice long time. Would this work? Should I connect it to the power connector (same as 9 volt) with a regular plug, or should I do something else? Any other inexpensiveish battery solutions for getting a long time with batteries (put 9volts in parallel, ? etc...)?

Thanks all!

Docedison

4 AA or bigger cells in series should be OK but marginally so as the regulator wants to see about a volt more in than it's output voltage for proper operation, there is a diode in series with the DCin jack + connection and that leaves 6V4 - .7 (4 X 1V6 = 6V4) or 5V7 to the regulator which should work ok for all but the highest current loads > 300 400 mA. The Problem is that the batteries output voltage will fall during discharge. A new unused AA Alkaline cell will measure about 1V65 - 1V7 and is considered dead at .9 - 1V1. 4 X 1V1 = 4V4 and the minimum required voltage is 5V7-8. 3AA batteries connected to the 5V source on the Arduino or 5 AA batteries connected to DCin should work fine. If the AA batteries aren't big enough (enough current/time or AH capacity) you can always go to a "C" or "D" sized cell, the voltage will remain the same but the larger batteries have higher AH capacity and thus are better candidates for powering your project.

Bob
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

rfmaster93

Thanks for your answer Bob! It has alot of information i'm having trouble deciphering, but I think I get the gist. So You are saying 4 'D' or 4 'C' Cells will also not harm the arduino? And also, do you think that the big 6volt ought to be ok? http://salestores.com/stores/images/images_747/MN908.jpg (For reference)

What is "4V4", "1V7" etc...? I have never seen "XVX" before and am not sure what you mean

Thanks again for the help!

James C4S


What is "4V4", "1V7" etc...? I have never seen "XVX" before and am not sure what you mean

Yes you have, it's on the Arduino board. Look at the power header next to the analog in pins... It's short hand for "4.4V". 

If you're killing 9V batteries in 20 minutes the isn't a surpise.  They aren't designed for more than 30mA. Above that and their life drops expontiontially.  Even 6 AA cells will work significantly better than a small 9V.

6V through the on board regulator is iffy at best. Draw too much current and it simply won't work.
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

Docedison

No I said 3 cells (4V5) connected to the 5Volt  source or 5 cells (7V5) connected to the DCin jack. I also said that for light loads 4 cells might work although you may have 2 problems. The first and obvious is that a batteries voltage decreases with use so at some point the battery is going to approach the point where it is below the required input voltage and that that point might well be above the "dead" cell voltage (.9V to 1V1) and second that even good new cells would be an issue with a heavy load as their terminal voltage will fall far enough to make the power supply unstable. which brings us back to 3 cells on the 5V source or 5 cells on the DCin jack.

Bob
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

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