LiFePO4 battery / UPS / power manager for Raspberry Pi

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- Ever wished you could unplug your Raspberry Pi and move it elsewhere when you were in the middle of something and didn't want to turn it off?
- Ever wanted to have your Pi run on battery power for a couple of hours?
- Ever wanted to have your Pi sleep most of the time, but wake up to do a short task at regular intervals, all while battery powered?
- Ever wanted your Pi to have a power button that would do a clean shutdown instead of just pulling power, even when you were using it headless?
- Ever had a high-availability application where you wanted your Pi to run through short power outages, and cleanly shut down and come back online when power returned?

If you answered "yes" to any of these questions, the LiFePO4wered/Pi or LiFePO4wered/Pi3 are for you! :)

The LiFePO4wered/Pi and LiFePO4wered/Pi3 can now be bought on Tindie:

The project is built on top of a LiFePO4wered/USB or #LiFePO4wered/18650 module. A small board is added with an MSP430G2231 microcontroller that takes care of monitoring input and output voltage, monitoring a PCB touch button, driving a power indicator LED and switching the load (the Raspberry Pi power). The microcontroller is also connected to the Pi's I2C bus and monitors the Pi's running state. The small board connects to 8 of the Pi's GPIO pins but leaves the rest free to allow prototyping using fly leads.

An Open Source software package is provided on the Raspberry Pi to interact with the LiFePO4wered/Pi. It contains a library that can be used in your own applications, a CLI interface to read and write device registers over the I2C bus and a tiny daemon that continually tracks the power state, and can initiate a clean shutdown when the battery is empty or the user wants to turn the Pi off using the touch button. Touch button parameters, voltage thresholds, auto boot settings, wake timer and auto shutdown timer (#LiFePO4wered/18650 version only) can be customized by the user and saved to flash.

The touch button requires press-and-hold to turn the Pi on and off to prevent accidental activation. The power LED indicates several power states: off (LED off), busy with boot or shutdown (LED breathing), on (LED solid on). The LED also provides touch button feedback: fade on during the press-and-hold delay, fast flashes when the LiFePO4wered/Pi cannot comply with the user input, either because the input voltage is too low or the Pi is busy booting or shutting down.

Normally the LiFePO4wered/Pi will wait for the user to press the button before it will boot the Raspberry Pi. Auto boot values can be set over the I2C bus so the Pi will automatically boot whenever there is enough battery charge, or when the USB voltage is present (#LiFePO4wered/18650 version only). There is also a wake up timer that can be set so the Pi can shut down, and automatically be started again after the wake timer expires. There are separate, customizable thresholds voltage levels for when the Pi is allowed to boot and when it will be instructed to shut down, or even forcefully turned off in case the daemon isn't active or fails to shut down the Pi. This ensures stable operation and over-discharge protection for the battery.

Based on testing with different Raspberry Pi's, a Model A+ and Pi Zero are able to run from the battery for over 2 hours. The B+, B2 and B3 take more power, but should be able to run for at least an hour. Run time will of course depend on system load as well. For UPS use, the #LiFePO4wered/USB based version is limited to low load conditions with the Pi Zero or Model A+, the #LiFePO4wered/18650 based version is recommended for UPS use in higher load conditions.


LiFePO4wered/Pi 5V version schematic

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LiFePO4wered/Pi 3.2V version schematic

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  • 1 × LiFePO4wered/USB (MCP73123-22JI version - LiFePO4wered/Pi) USB chargeable LiFePO4 power module
  • 1 × LiFePO4wered/18650 (LiFePO4wered/Pi3) High power USB chargeable LiFePO4 power module
  • 1 × MSP430G2231 Ultra low power microcontroller, 2K flash
  • 1 × MIC2876 (5V version) Boost regulator with bidirectional load switch
  • 1 × AP22802 (3.2V version) Bidirectional load switch

  • LiFePO4wered host software on LibreElec

    Patrick Van Oosterwijck03/30/2017 at 17:33 0 comments

    One of my customers, Raman Sarin, spent some time trying to make the host software work on LibreElec, a small Kodi distro that doesn't come with all the bells and whistles expected for compilation.

    I have not tested this myself, but here are his instructions verbatim in case someone else wants to give this a go:

    1. Get another SD Card and install Raspbian
    2. Go through the steps in the documentation to get the GIT depot onto your Raspbian install
    3. Edit the lifepo4wered-daemon.c file and change the shutdown function to this:
    void shutdown(void) {
      syslog(LOG_INFO, "LiFePO4wered/Pi triggered shutdown");
      char *params[6] = {"shutdown", "-h", "-t", "60", "now", NULL}; // shutdown halt in 10 seconds
      execv("/sbin/shutdown", params);
    4. Build the files
    5. Copy the BUILD directory to a USB stick
    6. Shutdown the pi and swap to the LibreElec SD Card
    7. Boot the pi
    8. SSH into LibreElec 
    9. Copy the files from the usb to sbin directory 
    	a.  cp /media/ESD-USB/LiFePo4wered-Pi/build/DAEMON/lifepo4wered-daemon /usr/sbin/
    	b.  cp /media/ESD-USB/LiFePo4wered-Pi/build/CLI/lifepo4wered-cli /usr/sbin
    10. Make the files executable chmod u+x filenames
    11. Make sure I2c is enabled by editing config.txt file
    nano /flash/config.txt (at the end)
    # Adding information to turn on i2c1 for later rpis
    12. nano /storage/.config/
    13. Now manually start the daemon so you can configure it
    14. Now configure it, I'm using the following, this makes sure the Pi starts up when plugged in and shutsdown cleanly when power is removed. However it also means you can't power it off in software it'll just reboot again.
    	a. lifepo4wered-cli set AUTO_SHDN_TIME 2
    	b. lifepo4wered-cli set AUTO_BOOT 3
    	c. lifepo4wered-cli set CFG_WRITE 0x46 
    15. Now reboot the Pi and start testing.

  • LiFePO4wered/Pi+ prototype

    Patrick Van Oosterwijck03/29/2017 at 22:41 0 comments

    Prototype PCBs for the higher power LiFePO4wered/Pi+ arrived from OSH Park, so I built up a prototype:

    I also hacked a #LiFePO4wered/18650 to charge at up to 3A instead of 1.3A as a base for this. This proved to be a bit of a challenge. The charger uses an asynchronous buck converter topology, and the little Schottky diode kept getting too hot and burning out. So I had to hack in a diode in a big SOD-128 package to make it work. It's still getting too hot but it's surviving so I can do the testing with this power manager. This is a basic problem with asynchronous converters: you can never get rid of the voltage drop over the Schottky diode, and at high currents, it becomes a power dissipation problem.

    The thermal image below shows the charger getting "too hot" when charging at 3A:

    The new TPS61235P boost converter is pretty amazing though. With the Raspberry Pi3 running with 4 cores at 100%, the CPU at > 100C, the boost converter is hardly breaking a sweat:

    Very nice! So time to put it on the electronic load and see how high it can go:

    And here is a thermal shot at this load current:

    I have to admit that eventually, the chip did a thermal shutdown at 1.8A. I lowered the load to 1.6A and it's been running for several days now (while charging, which provides a ton of heat on its own).

    Overall I'm very happy with this result. It's capable of providing twice the power of the current LiFePO4wered/Pi before going into thermal shutdown. The components were chosen to provide up to 3A, but I think I have to face the reality that in this form-factor, that is not going to happen. The PCB is just too small to provide any substantial heat sinking. If I want to get to 3A, I will have to change the design and go to a larger PCB.

    The #LiFePO4wered/18650 charger may actually be more of a limiting factor to get to 3A though. It's doing it in this prototype, but not at a healthy, mass producible temperature. I may need to look into a synchronous switching solution to get rid of the inherent voltage drop of the diode, which would always result in ~1.5W of power dissipation at 3A.

    In the meantime, this still provides a path to an improved LiFePO4wered/Pi3. 1.7A is a huge improvement over 0.85A. And even though 3A charge current seems to be out of reach for the #LiFePO4wered/18650, 1.8A may be a whole lot more manageable.

  • Power ping-pong

    Patrick Van Oosterwijck03/22/2017 at 20:22 0 comments

    It's funny how this project has evolved over time. It started with the #LiFePO4wered/USB, which I once connected to a Raspberry Pi as a demo for a Mini Maker Faire. It seemed to work well, and out of that the LiFePO4wered/Pi was born.

    Then people wanted to use the LiFePO4wered/Pi as a UPS for the Pi 3, which drew more power than the #LiFePO4wered/USB charger could support, so I created the #LiFePO4wered/18650 as a more powerful charger and the LiFePO4were/Pi3 was born.

    Now people are trying to power complete systems including hard drives and LCD screens from the LiFePO4wered/Pi3 and turns out it still isn't powerful enough. It seems the power craved by makers is insatiable. :)

    I have received reports of customers powering Pi 3s with LCD screens successfully, and others reported that this failed. The worst thing was that according to the reports the LiFePO4wered/Pi3 did not do a clean shutdown first but power just went away, indicating the boost converter went into thermal overload and switched off. I decided that instead of calibrating this with "it can power a Pi3 at 100% CPU", I needed to come up with some real numbers. So I got a nice electronic load from AliExpress and did some testing:

    Testing indicates that the maximum continuous load that doesn't cause the boost converter to go into thermal shutdown, at room temperature and with no extra cooling, is around 0.9A. The system had been designed with components rated for 2A, but on the tiny PCB it seems the boost converter just can't dump enough heat. Keep in mind that this is a thermal effect, so it takes time for the temperature to build up, meaning peak currents of 2A may be fine but are not sustainable over time.

    The LiFePO4wered/Pi was originally designed for a Pi Zero or Model A+ or B+ load, for which it works fine. Then the "ping" of making the charger more powerful made the LiFePO4wered/Pi3 possible, still using the same boost converter. But now people want to power all kinds of peripherals as well, and a "pong" to bump up the current capability of the boost converter may be in order.

    Luckily new and improved components arrive on the market all the time, allowing more powerful circuits in even smaller dimensions. One such component is the TI TPC61235P, which is a significant step-up to the MIC2876 I currently use. So I made a new layout based on this component and have prototype boards on order from OSH Park:

    Tight, but it all fit. Can't wait to test performance of these prototypes!

  • LiFePO4wered/Pi3 released!

    Patrick Van Oosterwijck12/20/2016 at 20:47 9 comments

    Kind of late I know, people following me on Twitter or looking on Tindie already knew. I had forgotten that I hadn't mentioned it here yet, sorry. :)

    So you can now buy a close-to-perfect power manager for the Raspberry Pi on Tindie! I wouldn't have dared to make such a claim about the LiFePO4wered/Pi, there were too many people who wanted to use it with the Pi 3 and who wanted input voltage monitoring and the behavior associated with that. But now that both these cases are supported with the LiFePO4wered/Pi3, we're getting there! :)

    A couple of things are still missing:

    • Adding RTC functionality would be great.
    • Some people don't need a big battery for long run times. They just want a small battery to shut down safely, but be able to run indefinitely at high load when plugged in. While the LiFePO4wered/Pi3 can be used for this, its battery is overkill. So... I have some ideas. :)

    If you like this and want to support my continuing development, please had over to Tindie and buy one!

  • Load tests LiFePO4wered/Pi3

    Patrick Van Oosterwijck12/13/2016 at 23:24 0 comments

    I did a couple more load tests with the LiFePO4wered/Pi3, the variant that uses the #LiFePO4wered/18650 as a charging base (and should be for sale very soon now). A lot of people seem to have applications where they want to use a Pi 3, use the LiFePO4wered/Pi as UPS, and also plug in a USB flash drive. Since flash drives are power hogs, I decided I should test some scenarios with a flash drive plugged in. So here are a couple of tests I did, with the LiFePO4wered/Pi3 charging from a 2A USB charger:

    • Pi 3, 4 cores @ 100%, ssh connection with a WiFi USB dongle (the built-in WiFi on my Pi 3 died), USB flash drive plugged in: slowly discharges (the system consumes more than the 1.33 A charge current).
    • Pi 3, 3 cores @ 100%, ssh connection with a WiFi USB dongle, USB flash drive plugged in: charges!
    • Pi 3, 4 cores @ 100%, ssh connection over Ethernet, USB flash drive plugged in: charges! :)

    I'm quite happy with these results. Systems running at 100% CPU continuously are very unusual. Using a WiFi USB dongle on a Pi 3 is very unlikely as well (unless breaking that silly flip chip without any protective packaging is common, which wouldn't be too surprising). I'm certain the on-board WiFi uses less power than a WiFi USB dongle, so I'm pretty confident that scenario with the CPU @ 100% will work as well. I really should get myself another Pi 3 some time so I can test it.

  • Firmware work

    Patrick Van Oosterwijck12/02/2016 at 21:14 0 comments

    I've been doing a lot of work on the LiFePO4wered/Pi firmware this week. Much of that was related to new functionality made possible by the ability to measure the input (USB) voltage with the new #LiFePO4wered/18650 base, but the quality time I spent with the code also resulted in some good improvements across the board, including for the standard LiFePO4wered/Pi. Here's a summary:

    • Auto boot when plugged in. Aside of the old "always boot when there's enough battery voltage" auto boot, being able to measure the USB input voltage enables the addition of an "always boot when there's enough input voltage and the USB power is present" function that so many people want.
    • Smart auto boot. It's fine and dandy to automatically boot when power returns, but it's kind of annoying if this prevents you from shutting the Pi down on purpose. Based on a suggestion from a user, I added smarts so that the auto boot only occurs if the system was shut down due to a low voltage condition, not when the user did a shutdown either with the touch button or from a program on the Pi. This is now an option for both the battery voltage based auto boot and the USB voltage based auto boot if it's available.
    • Auto shut down with timer. Many people want the Pi to cleanly shut down when external power goes away and boot up again when power comes back. This is now possible by combining the auto boot and auto shut down features (only with the new #LiFePO4wered/18650 base). The auto shut down will shut down the Pi if external power has been gone for a settable number of minutes. It is actually always active, but by default it's set to 65535 minutes and the battery won't last that long, so the feature is effectively disabled. :) If you want the Pi to immediately shut down when power goes away, set the auto shutdown time to 0. If you want the Pi to keep running across power outages up to 20 minutes, set it to 20. If the outage is longer than 20 minutes the Pi will be shut down with plenty of battery power left.
    • Improved wake timer accuracy. While implementing the auto shutdown timer, I implemented a new minute timer subsystem that's much better than the one I had for the wake timer. So now the wake timer also uses this new minute timer and benefits from much more accurate timing. It still uses the micro's internal RC oscillator, but it's much less dependent on variation due to other stuff going on in the code. As an example, I just ran a test of the auto shut down feature with the time set to 30 minutes, and it triggered a shutdown at 29:59. Nice! :)

    The improvements that are dependent on measuring the USB input voltage will be available when the version with #LiFePO4wered/18650 base goes on sale, the other improvements will be in every LiFePO4wered/Pi unit going forward!

  • Pi 3 testing with 18650 battery

    Patrick Van Oosterwijck11/24/2016 at 00:57 0 comments

    I'm making good progress on the new #LiFePO4wered/18650 base for Pi 3 versions of the LiFePO4wered/Pi, see this project log.

    Meanwhile I've been doing some stress testing on my first prototypes. I've been running a Pi 3 at 100% CPU for 5 days straight, powered from the prototype (plugged in of course), covered with a box to contain as much heat as possible, and it's been rock solid. Yay! :)

    So now that I have a new prototype that is pretty much identical to what I intend to run in production, I'm going to do the same test with it:

    First I'm having the battery run out, then I'll let the system charge while under high load for a week or so and see if everything behaves well. If it does, I'll go ahead and order production panels.

  • Pi 3: 1 hour @ 100% CPU!

    Patrick Van Oosterwijck11/17/2016 at 00:28 0 comments

    So previously I had tested that the LiFePO4wered/Pi with #LiFePO4wered/18650 charge board could be used with a Pi 3 with 4 cores at 100% in UPS mode. What I hadn't tested was how long it would last just running from a battery. I decided that this test was only relevant when run with production LiFePO4 cells. They arrived yesterday:

    So I ran this test today. Unfortunately, I don't have access to the thermal camera right now, but I can tell you this Pi is HOT! :)

    The results are in: 1 hour of run time with the Pi 3 at 100% CPU on all 4 cores and an active Ethernet connection! Very happy with this result. :)

  • Improvements coming :-)

    Patrick Van Oosterwijck11/10/2016 at 17:14 0 comments

      As I've talked to more customers, two wishes keep popping up:

      1. Customers want to use the LiFePO4wered/Pi as a UPS for the Pi 3.
      2. Customers want to know whether USB power is present, and have an option to auto boot when it is.

      So, work has started to make both of these wishes a reality. :)

      For the first request, the limiting factor in making the LiFePO4wered/Pi work well as a Pi 3 UPS is not the LiFePO4wered/Pi power manager itself--it is perfectly capable of powering a heavily loaded Pi 3. The problem is the limited charge current of the #LiFePO4wered/USB charger. It is limited to ~500 mA because of limitations of the AA LiFePO4 cell and the linear charge chip that produces a lot of heat. It works well for the power requirements of the original Raspberry Pi, but not for the more recent, high powered versions.

      To overcome these limitations, I have started a new project: #LiFePO4wered/18650. This is a drop-in replacement for the #LiFePO4wered/USB that is designed with a larger 18650 cell which allows higher charge currents, and a switch mode charger similar to the one I prototyped in the #LiFePO4wered/Solar1. This enables higher charge current without dissipating as much heat. I have running prototypes right now:

      This project also includes features to solve the second issue: detection of VUSB. Where the center two pins of the 4-pin header connecting the LiFePO4wered/USB to the LiFePO4wered/Pi used to be the D+ and D- USB signals, D- on the #LiFePO4wered/18650 by default will have ~25% of VUSB connected to it (this can still be reverted back to D- for those who need it with a solder jumper).

      But that's only part of the solution. The current LiFePO4wered/Pi power manager doesn't connect this signal to anything. So I had to make a change there as well. Since I was running low on LiFePO4wered/Pi panels anyway, I made a tiny change and added a trace to the LiFePO4wered/Pi to connect this pin to an ADC input of the microcontroller that was conveniently available before I ordered new panels. They have now arrived:

      My CM is building some new stock for me and part of the new stock will be based on these panels, so they will be ready and available by the time I'm ready to build production of the #LiFePO4wered/18650. Since the hardware at that point will be capable of detecting VUSB, it will only take a little bit of software work to make VUSB detection available! :)

      This brings up another issue. When I was first writing the LiFePO4wered/Pi software, my mind was very centered on the power manager by itself. So when naming the voltages, it made sense to name the incoming (battery) voltage VIN and the output (Raspberry Pi) voltage VOUT. I realize now that this is confusing to customers who deal with the complete unit: you'd expect VIN to be the USB input voltage instead. This will only get more confusing when I will actually have the USB voltage available as well. So I have decided to rename all current references to VIN to VBAT. I will update both the host software and the documentation to reflect this.

      I realize this may cause some confusion with current customers, but it seems to be the best option going forward. The longer I wait to straighten this out, the worse the problem will get. Existing customers can keep their software as is and continue to use VIN, or they can update their software with:

      git pull
      sudo ./
      This gets the update from Github (network required), rebuilds and then reinstalls the software to get up-to-date with the new VBAT names. I hope this won't cause too much confusion, sorry if it does!

  • New option: stackable header!

    Patrick Van Oosterwijck11/02/2016 at 18:59 0 comments

    Some users wanted to be able to use the LiFePO4wered/Pi in combination with other HATs and GPIO mounted modules. Good news: I now offer the option to have a stackable 40-pin header on the LiFePO4wered/Pi to be able to do just that:

    Here is an example of the LiFePO4wered/Pi used in combination with a HiFiBerry:

    If you were looking to do something like this, head over to my Tindie store and grab one! Stock is going to be limited for now until I can gauge the interest in this option.

    And please keep the comments coming! I love to learn from users what would make this product even better. :)

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Enjoy this project?



Walter E. Gunter, Jr. wrote 02/28/2017 at 02:04 point

so, dumb question... I just got mine today and plugged it in, loaded the software and can see voltage and have tested the auto boot function.  LOVE IT!!! I would like to put something like the little icons in the toolbar for ethernet and cpu to monitor voltage, but that's another topic.  If this battery is only 3.2V, but the pi3 needs 5V and almost 2Amps, can you explain a bit.  

My plan is to power a portable pi solution for my kids.   So, there will be a screen, but that's about it since i will use the pi3 bluetooth and wifi/ethernet running raspbian/pixel.   Typically, I would like a 3-5 hour play time without being connected to power.   Thoughts?

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 03/03/2017 at 20:12 point

The circuit has a booster that brings the 3.2V up to the 5V used by the Pi.  It is a limiting factor and cannot provide 2A continuously due to thermal shutdown of the booster on the tiny board.  It might not be able to provide enough power for the screen.

  Are you sure? yes | no

Walter E. Gunter, Jr. wrote 03/06/2017 at 02:25 point

I have successfully been using it with the PiTft Capacitive , no shutdowns. no low power icons...  I am not sure what to do to get it to worst case scenario. I have launched wolfram alpha, browser, minecraft, etc.   Nothing seems to kill it  (ie, i haven't seen it shutdown or die due to too much power draw).  I have some plans for this to be a touch screen interface for a few things and love the .  I didn't realize the power of the 18650. I actually have two of them from a local make supplier here in Salt Lake City, UT.    I will use them with a power boost, but they don't have the UPS type software you have created with this.   
Alternate thought: I am having issues with fully powering off.  If I press the power button, it powers off, but the red led is still on, and i can't turn it on (ie, i get the fast blinks since it cannot take another command).   Thoughts?

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 03/06/2017 at 20:26 point


Nice to hear it's working for your setup with a touch screen!  The fact of the matter is that there's no way for me to test as many different configurations as my customers can, so it's always nice to hear what works and what doesn't.

As for your LED question, it's normal for the red LED to stay on a while after you turn the system off.  It indicates charge status, which is separate from the power manager.  Even if the battery is mostly charged, once the load is gone, the charge controller will top off the battery until it reaches charge termination.  Then the red LED will go off.

Not sure why it would refuse to turn back on though.  The fast blinks would indicate the Pi is either externally powered, or the battery voltage is too low to start.  Maybe the Pi + LCD takes enough power to make the battery drain even when it's plugged in?  It's possible you turned it off in the hysteresis area between where a shutdown is forced and when boot is allowed.

  Are you sure? yes | no

ActualDragon wrote 02/02/2017 at 18:48 point

if you have such a problem with it, build your own. that's why ur an engineer. get out and try it yourself instead of #failing it. personally i think it's a little expensive, but i understand the whole business part. just don't buy it

  Are you sure? yes | no


[this comment has been deleted]

davedarko wrote 02/05/2017 at 17:16 point

Seems like they're simply analysing your comment as rude behaviour, too ;) No engineering flaws were pointed out buy you, only financial decisions you probably have never had to make. Sure, It's probably cheaper to order all the parts he mentioned and design a little board around them for yourself. But selling is a whole different story, you want to take money for your work time as well and have some margin for faulty boards and all that. Hope that helps to understand the pricing :)

  Are you sure? yes | no

davedarko wrote 02/05/2017 at 17:32 point

Those who are selling shields/hats for the PI not responsible for the pricing of the Raspberry PI itself and I'm sure they're still selling some shields that it makes sense for them, even knowing that those can easily double the price of the system. So I don't think it's fair to come here and 'spit' your thoughts on a very well documented project and tell that it's overpriced and "over-documented" :D 

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[this comment has been deleted]

Patrick Van Oosterwijck wrote 02/01/2017 at 22:46 point

Eh?  Of course it costs more than a Pi.  Everything does.  If you're an engineer you should know why.

  Are you sure? yes | no

EngineerAllen wrote 02/01/2017 at 23:01 point

the components & pcb have almost no cost even in low quantities (from china)

how much are you being charged to get them populated?

i havent made products just do my own soldering

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 02/02/2017 at 00:06 point

Then I suggest you make a product and try to build a business around it before you go around declaring other people's hard work to be #fail.  There's much more involved than component cost and soldering.

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 02/05/2017 at 17:57 point

Seriously, go troll elsewhere.  This project has been well received beyond my wildest dreams.  I'm very happy most people understand the concept of overhead, and the only place it seems to have failed is in your head.

If you're here to analyse engineering ability then I'll save you some time and let you know right now that I'll never do business with you.

  Are you sure? yes | no

ajlitt wrote 02/02/2017 at 18:14 point

Low volume hardware manufacturing is expensive, especially if you're in the U.S.

Also protip: don't troll from an account with your linkedin page linked at the top of your profile.

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davedarko wrote 02/05/2017 at 17:27 point

@EngineerAllen - I don't see any reason to call people names, would you please keep it nice? this is not the comment section of the hackaday blog.

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EngineerAllen wrote 02/05/2017 at 17:44 point

@davedarko youre pointing the blame at the wrong person

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f.hillhouse.jr wrote 01/23/2017 at 22:05 point

Greetings! I am looking at the final product and am curious about the overall interface to the RPi. I see that I2C is used. I also see that
the product connects to one of the UART pins (UART_TXD). Does the product use the serial port or GPIO? If GPIO, can this be moved to another pin? I am working with a Zero and am using the UART already. Also I assume I can still use the I2C for additional hardware (e.g., display).

Thanks and best regards!

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nrrdzilla wrote 01/24/2017 at 22:37 point

I'm also interested in this. As someone just getting into using RPis; I'm not sure what the implications are.

Specifically I'd like to know if we can just cut the trace and flywire to another GPIO, like maybe GPIO4, since we already have that signal (unused) in the header? Is there anything (except for software changes) that would prevent this?

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 01/30/2017 at 15:58 point

You can actually still use the UART_TXD in your project!  All it is used for in the LiFePO4wered/Pi is to detect that shutdown has happened, so it knows the power can be turned off.  This is only monitored in the shutdown state.

All communication between the Raspberry Pi and LiFePO4wered/Pi goes over the I2C bus.  As long as the software that uses any other I2C devices on the bus is well-behaved (doesn't hog the bus but uses short open/communicate/close sequences), there should be no problem using them together with the LiFePO4wered/Pi.

I sell a variant that uses a long-tail 40-pin connector instead of the small 8-pin connector, this can be used when you want to stack other HATs.

  Are you sure? yes | no

jason wrote 12/27/2016 at 23:50 point

I want to connect this to an existing project that is using pin2 (5v) to power something.  Is there a recommended place to solder a wire beyond the backside of that connector?

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Patrick Van Oosterwijck wrote 12/28/2016 at 01:21 point

No, I think the backside of the 8-pin connector is the easiest place I can think of.  Other than that, the output capacitor is another spot that can be reached, even though it's on the bottom (between the 2 PCBs).

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Mikey wrote 11/28/2016 at 19:37 point

Are you planning on releasing it with the option for a JST battery connector? -- I'd like to use it with one of the bigger Adafruit 6600 mAh batteries to make a portable handheld game (RetroPI, etc.). -- Also, is this compatible with 3.7v / 4.2v batteries, or only 3.6v / 4.1v?

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Patrick Van Oosterwijck wrote 11/28/2016 at 19:45 point

No plans for a JST connector version, no.  Partly to prevent the scenario you just described. :)

Anything with a JST connector is usually a regular LiPo, which would likely blow this up.  It's only made to work with a LiFePO4 which has a 2.7-3.6V range during the whole charge/discharge cycle.

I'm having one in the works with a 1500 mAh LiFePO4 (see #LiFePO4wered/18650), and nothing prevents you from putting more LiFePO4 cells in parallel.  Some customers have ordered without the battery and hooked up their own large cells, and this is fine as long as they're LiFePO4.

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Patrick Van Oosterwijck wrote 11/25/2016 at 18:59 point

Thank you for the feedback! :)

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kaislahattu wrote 10/25/2016 at 21:11 point

Could this be used with considerably larger cell capacity? (without the battery holder and with "duct tape", accepting really long charge times)

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Patrick Van Oosterwijck wrote 10/25/2016 at 22:23 point

Yes you could, in fact one of my customers ordered the top PCB (power manager) without the bottom PCB (charger + battery) and connected his own battery system.  You can contact me on Tindie for such custom requests.

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Alexander von Gluck IV wrote 10/15/2016 at 00:53 point

How do you turn it off when a Pi isn't attached?  Pressing and holding the button just results in a rapid blink, then back to fade.

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Patrick Van Oosterwijck wrote 10/15/2016 at 01:46 point

The LiFePO4wered/Pi isn't really made to work on its own, only in tandem with a Raspberry Pi.  When you turn it on, it's waiting for the Pi to report that it has booted and is ready to accept a shutdown command.  Only then will it accept new commands to turn off, because the Pi is able to do a proper shutdown.

When no Pi is attached, the LiFePO4wered/Pi will stay in the state waiting for the Pi to boot, which of course will never happen.  It will indicate it can't accept your command by rapidly blinking the LED when you touch the button.

If you happen to turn it on with no Pi attached, the best thing to do is momentarily disconnect the battery.

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Anthony Webb wrote 10/10/2016 at 21:33 point

I just bought one, excited to kick the tires.  Only downside I see here is there are not a lot of case options (outside of the acrylic one which is not great).  Have you thought about or would it be possible to re-orient stuff such that more case options would work with your design?

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Patrick Van Oosterwijck wrote 10/10/2016 at 21:45 point

Thanks Anthony! I'm hoping that more case options may appear as the product becomes more known.  I have to say I'm not super familiar with what's out there for Raspberry Pi cases, but I'm not sure if any orientation would work in an existing case.  A battery needs a good amount of space somewhere. :)

I'm working on a case design myself, a layered acrylic case.  If you're not a fan of acrylic cases it's probably not going to be of much help to you. :)

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James Avery wrote 09/23/2016 at 10:45 point

This looks great! Mine just arrived, so I'm looking forward to trying it out!

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James Fowkes wrote 09/14/2016 at 12:37 point

Have you had any issues with i2c clock stretching? It's been a problem in the past with the pi:

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Patrick Van Oosterwijck wrote 09/14/2016 at 14:40 point

I've run into this problem with a different project, and I had to reduce the Pi's I2C clock to 50 kHz to make it work because of the lack of decent clock stretching support (the slave I2C was completely implemented in software on that one).

I have not had any problems with the LiFePO4wered/Pi though.  The micro I use has a hardware peripheral for I2C (although I still had to implement more than expected in software), and it seems to respond fast enough so the Pi can use the default 100 kHz clock.

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Adnan Kurt wrote 09/02/2016 at 12:17 point

Nice project. Thanks for sharing. Is your MSP430 code open? Or should we buy the unit?

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Patrick Van Oosterwijck wrote 09/02/2016 at 14:49 point

It isn't open yet, but I fully intend to open source it once I have achieved some return on my investment by selling units.  I have to figure out how many units I should sell before that happens.  You can speed that up by buying one, the release sale is still going on! :)

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Adnan Kurt wrote 09/02/2016 at 15:12 point

Now I've noticed the sales link. Thanks for reminding. Keep up with nice work! :)

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Renos wrote 08/29/2016 at 05:50 point

Excellent work. Can't wait for it to be available for purchase :)

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Patrick Van Oosterwijck wrote 09/02/2016 at 14:45 point

Thanks Renos.  You can now buy it on Tindie:

The release sale is still going on, so hurry if you want it cheap!

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Renos wrote 09/02/2016 at 14:47 point

Already ordered 2. Saw the news on twitter and ordered immediately :)

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CaptMcAllister wrote 08/11/2016 at 21:04 point

This is a very cool project.  I used to get questions on whether my AA voltage booster could power a raspberry pi, and I always had to say definitely not.  Even two in parallel couldn't.  I'd refer people to this project as the "right" way to do it.

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Patrick Van Oosterwijck wrote 08/11/2016 at 21:31 point

Thank you for your kind words.  It takes comments and encouragement like this to get projects from prototype to production.  I appreciate it! :)

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CaptMcAllister wrote 08/11/2016 at 21:38 point

You're welcome.  I think you'll achieve some very nice sales with this.  If you have any questions about crowdfunding, feel free to contact me.  My modest campaign was successful and I learned so much.  I'd love to share the lessons I learned the hard way!

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Patrick Van Oosterwijck wrote 08/11/2016 at 22:19 point

Thanks!  I considered doing a crowdfunding campaign, it's definitely nice to be able to have a known set of customers before you start building product.  But it seemed like it would cause a lot of extra stress that I could do without.  Then I received the $1000 grand for being a Hackaday Prize finalist and that made it possible to do the build without crowd funding.

Of course, if you're right and I do get a lot of sales, things may turn out to be just as hectic. :)

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atlrob wrote 07/08/2016 at 21:12 point

Have you considered making one layout using the adjustable version of the MIC2876 rather than maintaining separate layouts for 3.2v and 5v?  (Position the voltage divider resistor pads to make hand SMD soldering/tinkering possible.)

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Patrick Van Oosterwijck wrote 07/09/2016 at 04:14 point

There are two reasons not to do this.  First of all, the layout is really tight and I don't have room for external voltage divider resistors.  More important though, the only good excuse to power the Pi with an out-of-spec voltage of 3.2V is the increased efficiency of directly feeding the battery voltage to the Pi, without using a boost converter.

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hyperzap wrote 05/16/2016 at 01:53 point

In the 3V version, are you just feeding 3.2V-4.2V into the 5V pin of the Pi and so far it has no worries? Can I do that? (I want to power my Pi with a LiPo without a boost converter, just wondering if this approach has any issues in a setup without any USB devices but using ethernet).

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Patrick Van Oosterwijck wrote 05/16/2016 at 16:01 point

Yes, the 3.2V version just feeds the battery voltage into the 5V line and it works beautifully, I've had no issues whatsoever.  The reason is that the Pi, and most USB devices actually just convert the 5V to a lower voltage anyway to power the chips.

I've decided that since I want to sell this as a product, I'm going to produce the 5V version first to avoid any complaints about powering the Pi with an out-of-spec voltage.

But sure, for your own hacks go ahead and power the Pi directly from the battery, it will work fine for the Pi and should be OK for most USB peripherals such as Bluetooth and WiFi dongles.

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hyperzap wrote 05/16/2016 at 22:47 point

Awesome :) Out of curiousity, did you ever profile what the cutout voltage was (ie: the voltage it which the Pi was unreliable or reset)?

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Patrick Van Oosterwijck wrote 05/17/2016 at 15:34 point

In the LiFePO4wered/Pi, I instruct the Pi to shut down at 2.95V.  I think in my testing it started to become flaky at around 2.7V.

Of course this was just at room temperature and not across a statistically relevant sample of Pis.  Since I have no way to get such data, this uncertainty is another reason for me to choose the 5V version for production since it follows the Pi spec.

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Mario Ray Mahardhika wrote 04/19/2016 at 17:05 point

I'll be waiting for production release, having a full smartphone size portable computer is fully achievable by that time :)

I wonder if you're willing to create more battery slot version as if I'm gonna use it with 5" LCD touchscreen + Pi 3 (instead of Pi Zero), it certainly will require big battery power.

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Patrick Van Oosterwijck wrote 04/19/2016 at 18:51 point

I have been wondering about that myself.  In principle, I can just add parallel cells to increase capacity.  The only problem is that the little charging chip would take quite a while to charge a larger capacity cell, since it has a 1A limit.  USB chargers have similar limits though.  I'm starting to look into USB Type C.

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Steve wrote 03/19/2016 at 08:14 point

+1 for Kickstarter. What do you expect one would cost retail? I'm very interested in a few but the default 30$ for these devices is a little much for my taste.

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Patrick Van Oosterwijck wrote 03/21/2016 at 17:17 point

Thanks Steve!

I'm adding a project log about the cost issue...

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bagdala wrote 03/18/2016 at 07:59 point

I have this one:

But I have to admit yours look much more appealing . I'm in line for one!

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Patrick Van Oosterwijck wrote 03/18/2016 at 17:03 point

Cool!  I'm not sure if it's too bad or a good thing I didn't know about it... If I had, I may not have bothered making mine! ;)

Very impressed you managed to do a successful Kickstarter.  I'm considering doing one for this project but I'm not sure if I can play the marketing game well enough to make it succeed.  Any tips you could share on what worked well and what didn't?

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bagdala wrote 03/18/2016 at 17:09 point

Sorry if i misled you, I meant to say I purchased this one. I'm just a end user not involved in development of particular product in any way. 

That being said, go for Kickstarter you can't fail ! You definitely have market  for it. 

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