I am trying to make my Raspberry Pi 3A+ more portable by making it more battery powered. I used a Pololu 5V 3A Step-Up/Step-Down Voltage Regulator S13V30F5 with an input power from 4 AAA batteries. The Rpi has a max 5v 3A with the pololu providing between 2 to 4A depending on volatge. No problems with connections and it started a boot up but failed to complete it. I went to Rpi forums and they told me it was a lack of volts and current at boot. So some help on a compact battery to use for my portable project using pololu volt reg would be much appreciated. Would using 4 AA or perhaps a 9v be okay?
I deleted your second thread since it was nearly identical and this one was posted in a more appropriate section.
It would probably be good to determine if the source of the problem first (i.e. is it the regulator or your batteries), although I suspect it is the batteries since AAA batteries are typically not as good at handling high current draw as other batteries. To be sure, I suggest measuring the voltage output of the batteries while you try booting the Raspberry Pi to see how much it dips under load. You could also try new or freshly charged AAA batteries to see if it makes any difference.
Generally, AA batteries should be better for higher current draw applications than AAA, and AAA are better than 9V. However, the battery chemistry (i.e. Alkaline vs rechargable NiMH) and quality are also worth considering. Another popular option for high-current applications is LiPo batteries (especially if you want something smaller and lighter).
I’m working on a similar project (yet to be started) whereby my intent is to power a RPi4 and a 10” monitor from a deep cycle battery (12VDC 35A) or any other battery with high current availability. I think my total current draw is about 5 amps or so. I purchased the D36V50F6 rated at 6VDC output. I’ll then pass that through a 5V regulator to get to my input voltage. My reason for taking this route is that I want to run the RPi4 with a software defined radio and software, but am concerned about the radio frequency interference generated by the step-down V regulator. My hope is that I’ll be able to reduce the RFI via the 5V regulator. From what I have read so far, I may end up beating a dead horse, but I’m going to give it a shot. My two cents worth is that perhaps a small rechargeable LIFePO4 battery at 5A might be a better option. It your intent is to run it off of easily available AA or AAA batteries I would wire them in series/parallel to get the amperage up higher.
Good luck with your project.