Picture of LiPo-Powered Arduino
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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!

If you think this is a good tip, please vote for this Instructable in the Electronics Tips and Tricks contest!  The vote button is in the top right of this Instructable, right above the title. Thanks!
SoHa SMART18 days ago

Hello, what is your advice on using 3S Lipo's with Arduino? I have a bunch from drone use.

tym3k6 months ago

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 :)

Is that possible? Maybe with a battery management chip like the MCP73831?

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!

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&LiPoConfig=2&sortlist=W&CatSortOrder=asc

retrolefty2 years ago
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
battery voltage and regulate it to +5vdc for direct connection to the arduino 5V pin
or better yet hack a old spare USB cable, lop off the PC end and connect the ground
and positive wires, connect to regulator output and plug into arduino's USB connector.

davr.org3 years ago
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.
Radioactive_Legos (author)  davr.org3 years ago
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