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Need a USB battery recommendation for Pi 4



  • Now that I'm done with the controller mounted Pi 3B, my next project is going to be a switch-like console using the Pi 4. It is going to be a clamshell build using a 7" HDMI display (https://www.adafruit.com/product/2300) that I already have. The display draws 500mA and from the benchmarks I've seen of the Pi 4 it draws 1280mA+. Most of your USB batteries have a total output of 2100mA even if they have more than one USB output.

    This model here has up to 6A draw and 26800mAh capacity. https://smile.amazon.com/dp/B01JIWQPMW/ref=emc_b_5_t

    Does anyone have experience with this battery or know of a better choice?



  • I'll throw my 2 cents in, that battery looks good, but consider the weight. It's a tricky balance finding a battery that can supply enough juice so you don't get low voltage warnings, but not weigh a ton. I just finished a similar project, but with 3 B+ and 7" screen. At first I used a 3.7V 10,000 mAh battery which had roughly 6 hrs runtime, but was very heavy to hold. The 7" screen is pretty hefty to begin with then the battery added 181g. When playing it felt trying to hold a brick and my hands got tired quickly. The battery you posted (according to amazon) weighs 490g.
    I ended up going with a 3.7V 5000 mAh battery which is 90g and it was much more comfortable to play.
    I'm kinda comparing apples to oranges though as a usb bank it quite different from a 3.7V single pouch cell, with the bank you get a lot for "free" as far as battery management. when testing my first 5000 mAh cell I left the room for a few mins, came back and found the cell drained down to 0V and I had to scrap it. My first build used a 10,000 mAh bank and I always got low voltage warnings so I went this direction to solve that problem, but I have experience building packs for RC projects so this solution is not for everyone.
    So yeah, I didn't really answer your question, but hopefully gave you some things to think about, best of luck with your project!



  • Yeah, it weighs half a kilo! I used https://www.adafruit.com/product/4288 in my controller mounted build with a 3B, but it draws around 900mA at high load and the display only 150mA. I suspect the controller draws something in the 50-100mA range because I'm getting around 4hrs of battery life.

    The Pi 4 is a lot hungrier and I'll be adding a compact keyboard, touch screen overlay, and other assorted bits. 2.1A total output ain't gonna cut it. Anker has some really small and light packs in the 20000 range, but they don't have a higher enough total power output.



  • Sounds like you're on the right track, it's a tricky balance between playtime vs weight. I have a pile of unused batteries I tried while building mine.

    Clamshell with keyboard is an ambitious project, best of luck and I can't wait to see some pics of the build and/or finished product!



  • @mud2005 As I commented on another thread, my case building skills need a BIG catch up to make it look good. The controller mount has a great feel and is very playable, but still looks ghetto AF. My very first build was in a machining instrument case, which was WAY too big, but the hinged lid was ideal for housing the display. I might cheat and go that route so it doesn't look like a hammered turd.

    My electronic skills are up to the task though, so I got the important parts covered. :)



  • Funny you should mention that, I spent 2 years building the "perfect" case IMO and in the end it looks good, but I'm developing arthritis in my hands and I'm not 100% satisfied with the comfort. I just ordered some parts to make a controller mount build so I have something more playable and ergonomic.



  • It's the battery I use for my Pi's on the go. Kali hacking, mostly.

    Weighs a ton, but lasts for days. Crack open any device like a Kindle, phone, tablet, and most of the real estate is battery.

    That would squeeze in a case, I could tolerate the weight.

    The Pi4 gets plenty hot. A heatsink does it for me, but I don't know if cramming it into a case will do any favours. i'd plan for that. I plan on knocking out a handheld very soon. Let us know how you get on.



  • The Pi 4 is currently in a Canakit case with heatsinks and fan, which I'm going to incorporate into the bottom of the hinged case. It stays pretty cool in there so I'm going to try and keep the airflow. I'll need enough room for it, the battery, the driver board for the display, and keyboard. I have a mini keyboard but trying to find something just a shade larger.



  • I might go with this one https://smile.amazon.com/gp/product/B07XQ94ZL9 it appears to be quite a bit lighter, cheaper, and can supply 3.1A (one port at 2.1A and one port at 1A). I can power the display, keyboard, and audio off the 1A port and it should leave enough for the Pi 4.

    EDIT 1/27/20: I went ahead and ordered this battery, I've burn in tested my Pi 4 config using my 50,000mAH battery's 2.1 and 1A USB outputs and everything looks good so far.



  • Initial burn in test of this battery (https://smile.amazon.com/gp/product/B07XQ94ZL9) gave a life over 8 hrs with the Pi 4 running Ergheiz (a very demanding MAME game) in demo mode with a keyboard, two controllers, USB stick, and the HDMI display. Didn't have any power supply issues. I'm going to cobble together a prototype case and see how it fares in portable use.



  • Use a 5000 mAh PocketJuice portable charger.



  • The problem: They are THICK. Like a centimeter. But you can always cut it open.



  • @IceChes1 That would run a Pi 4 under load for a bit over 2hrs.



  • True, A 4 would not be able to deal with a portable charger. Maybe try a Li-Po. They sell them at any hobby shop. That, however, I cannot help you with.



  • Thanks, but don't need anything more, that 25800 mAh battery (https://smile.amazon.com/gp/product/B07XQ94ZL9) is working very well. I've done 3 day-long burn-ins and it went over 8 hours each time. Parts are arriving today for my prototype portable build and I'm going ahead with that battery.


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