> A 3A boost/buck converter to power the Pi from a battery is not going to be cheap, either.
LM2596 costs <$1 and it powers my rtl-adsb for 4 years so far (yes, this is in step-down mode, but you either want a 2S/3S battery anyway, or you use the similar step-up chip).
I am not doubting your claim, but it makes me wary since all the "cheap" wallwarts that claimed "2.5A" and now "3A" ran about $10, whereas the official RPI wallwart is double that (maybe $18), and a really awesome 5V PSU that can run two rpi at full TDP costs between $35-$120.
I have a bunch of "QC3.0/3A Buck converters" for 6-36VDC to USB-A, maybe i should try to run a pi on a SLA Gel 12V battery.
I think MEAN WELL LRS-50-5 (5V/10A) can easily run 2 or even 3 Pis at full power and costs $13 ($15.5 incl. VAT) at EU reseller. Or is it not "awesome" enough?
LM2596 costs <$1 and it powers my rtl-adsb for 4 years so far (yes, this is in step-down mode, but you either want a 2S/3S battery anyway, or you use the similar step-up chip).