Why the PBP?

Lately I've been thinking a lot about power consumption when it comes

to computing. Intuitively, I know that arm devices pull significantly

less power than amd64 machines but I've never really tested this in the

real world. So, some preliminary power consumption stats:

big amd64 laptops (thinkpad x220 and t490) pull at most 65

watts

small arm SOCs typically pull at most 15 watts

most android phones pull at most 18 watts

Pentium 4 pulls at most 250 watts

These numbers are fairly easy to find: just look at the power supply

for a MAXIMUM OUTPUT value or something similar. This is the point at

which the power supply fails so we can safely assume this is the maximum

power draw for any given computer. Of course, this is DC output and not

AC output and anyone who knows anything about electricity knows that

converting AC to DC is expensive but these values are useful as a

general estimate. I

wrote something similar about computer power consumption some time

ago

My goal in all of this was to find a self contained computer that

runs UNIX, doesn't take much power, isn't a consumption rectangle

(smartphone), and can be charged from both AC with a rectifier and

stored DC without an inverter. Charging from existing stored power was

probably the most novel consideration. Everything else is a given.

A few obvious answers come to mind:

Raspberry

Pi 4 is not self contained and using a pitop in public is a good way

to get the bomb squad called on you

beaglebone black is good

too but neither self contained nor popular enough for wide OS

support

Pinebook

Pro is self contained and is supported by some of the operating

systems I'd like to run

The PBP is an obvious choice. It's an open hardware ARM laptop that

can be charged via a barrel cable (AC->DC) or via USB-C. Charging

from USB-C is a very useful feature because it means I can easily choose

between charging from the mains where efficiency loss is acceptable and

charging from a DC source where efficiency loss is unacceptable.

The actual use case is "what computer can I run off of a old car

battery or the alternator in my car without burning power with an

inverter?". I'll revisit this use case in a later section.

Initial notes

I took these notes immediately upon opening the PBP. They remain

unedited because I want to be honest on the first impressions.

shipping

I was worried about DHL dropping my package out of a plane. Or

leaving it out in the rain. Or having one of the employees use it as a

soccer ball. Or having the thing get stuck in customs. It ended up

arriving safely and was packaged well. Two boxes within a padded

envelope within another envelope. Surprising for DHL.

hardware impressions

Touchpad sucks and trackpad scrolling sucks (it's probably just

KDE). Installing synaptics drivers allegedly fix this problem.

keyboard is comfortable, clickly, full sized despite being a

chicklet keyboard. I don't like that the <ctl> and

<fn> keys are backwards when compared to a thinkpad.

I really like the thinkpad keyboard layout.

Shift+enter seems to type the M character. My muscle

memory for key chording is now broken. This appears to be a fundamental

design flaw with KDE.

Passively cooled, gets a bit warm.

display is sharp (IPS) and almost too high resolution for my eyes

(1920x1080 instead of 1366x768). I can fix this in software.

enabling/disabling mic/wifi/came