Let's face it, 9V batteries suck.  They don't last long, they're expensive, and did I mention they don't last long?  I work on and run several electric RC cars, and because of  this I own a lot of Lithium Polymer (LiPo) batteries.  Nowadays you can get them for pretty decent prices, and if you know how to take care of them (don't ever use them if you don't) they'll last you a long, long time.

While your average pile alkaline 9V has a capacity of about 565mAh and costs somewhere around $2, a budget 2S (7.4V) LiPo pack that costs $9 can have a capacity of 1800mAh, with the bonus of 1,000+ charge cycle capability.

To use my LiPo packs on my Arduino, I made a simple adapter from Deans Ultra (the type of plug I have soldered onto all my LiPos) to the barrel plug that fits into the Arduino.  Make sure that when you use a LiPo for an extended period of time, or any time at all for that matter, always connect it to a low-voltage cutoff (if your LiPo drops below 3.0V per cell, you're pretty much dead in the water).

Now I can run my Arduino away from the wall or computer for long periods of time and for a low cost, and you can, too!

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<p>Plugged my 3s lipo at about 10 volts into my arduino micro. I smelled smoke and unplugged it. Now it seems to be broken as my comuter wont recognize it and the 5v pin isn't outputting power when powered by usb. Any ideas??</p>
<p>You could have also plugged it into the wrong pins on the Arduino, I suppose.</p>
<p>According to Arduino.cc, an Arduino Micro (current rev) should have a voltage input range of 6-20V. A 3S LiPo will never exceed this, so either your Arduino has a different voltage range, or you plugged the battery in backwards. Not sure if the Micro has reverse polarity protection like some of the larger models do.</p>
<p>Hello, what is your advice on using 3S Lipo's with Arduino? I have a bunch from drone use. </p>
<p>As long as it's within the Arduino's working voltage range it'll work just fine. A 3S LiPo is 12.6V fully charged and 9V fully discharged, so compare this with your Arduino's spec sheet to see if it'll work!</p>
<p>is the discharge rate of 35c a problem because the arduino can only handle 2 amps.</p>
<p>Nope, the Arduino will only draw as much current as it needs.</p>
<p>How to know when a battery runs low to recharge it? I don't mean when it shuts down but to implement battery percentage in software :)</p><p>Is that possible? Maybe with a battery management chip like the MCP73831?</p>
<p>great idea! unfortunately that LiPo battery looks really big =/ i'm making a gps for my cat, so the smaller the better and if that means changing the battery every few days, oh well. but hopefully i will be able to find out where he goes without me. if you know of a smaller version of the LiPo, let me know!</p>
<p>Hey there! LiPos come in about any size you can think of. Here's a list of all the 2S LiPos sold by HobbyKing, ranked from lightest to heaviest: http://hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?idCategory=86&amp;LiPoConfig=2&amp;sortlist=W&amp;CatSortOrder=asc</p>
Yes in this day and age there makes little sense to use batteries to drive linear regulators. Here is a simple DC/DC switching regulator that could take this Li-po <br>battery voltage and regulate it to +5vdc for direct connection to the arduino 5V pin <br>or better yet hack a old spare USB cable, lop off the PC end and connect the ground <br>and positive wires, connect to regulator output and plug into arduino's USB connector. <br>http://www.ebay.com/itm/251066005460?ssPageName=STRK:MEWAX:IT&amp;_trksid=p3984.m1423.l2649 <br> <br>Lefty
Running a 9V battery through a 5V linear regulator (as on the arduino), wastes 44% of the battery power right off the top (4V of that 9V gets turned into heat, which is why the regulator gets so hot). Linear regulators are terrible for running off battery. Their main advantage is they are cheap and provide a very clean output voltage.
Good point! The batteries I use here are 7.4V nominal, so the drop is lower. The main purpose of this Instructable is to demonstrate how Lithium Polymer batteries can be integrated into an Arduino project for longer runtime and lower cost in the long run.
I would recommend running a non-linear BEC with 5V output and power the Arduino using the 5V input pin to be more efficient. Even if you burn 33% in heat that's 700mAh compared to the 175mAh on my 9V NiMH battery :-o

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Bio: A Bay Area native interested in electronics, mechanics, and robotics, and automobiles. Formerly the electronics captain of Team 100 in the FIRST Robotics Competition, I ... More »
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