An update on the Farphone's battery (opens in new tab)

Apparently not a misspelled Fairphone, as I originally thought. I wouldn't mind an article about that battery.

No actually, it is a Fairphone after all.

Your answer lies on https://far.computer

In short, far phone is the phone which powers far computer which is in turn served from https://far.computer

> this webpage is hosted on a drawer-bound fairphone 2, running postmarketos

https://far.computer/how-to/

“Farphone” is a given name of a specific fairphone (android smartphone) that the author uses to run their web server.

The name likely comes from “fairphone” with the “i” scraped off - see the photo: https://far.computer/

I've had success using a large capacitor instead of the battery. To keep it charged I connected its positive leg to the 5v USB pin through a diode.

I was pleased to discover my old PinePhone allows this. It makes development much easier when having to swap the SD card every few minutes, and allows for simple power cycle via USB switch.

What I cant figure out is how to detect power usage from the PMIC when in that configuration. ie seems to still assume power draw happens via a battery.

That can't be true right? PD (and some Chinese standards) have insane wattage allocation/allowances, there's no way that a mobile CPU can pull over that amount, it's more that they don't support it.

Unlikely a web server would see such usage patterns.

You can’t be too cautious with spontaneously combustible stuff.

I'd like more details. Many devices won't run on USB cable alone: they won't start without a battery as well.

Yup that's right!

That's what the project cited as inspiration does: compost.party

an even smaller https://solar.lowtechmagazine.com/about/the-solar-website/ ?

All of the controllers do that! But then battery starts to self-discharge, eventually a controller detects "huh, the battery is no longer charged" and start charging again.

Over years, this can accumulate enough charging cycles so battery gets worn down.. And old batteries have even higher self-discharge, so the cycle accelerates. If you are lucky, the battery lasts long enough. If you are unlucky, you end up with "spicy pillow". If you are super unlucky, and charger's temperature sensor fails (or was never installed), or battery gets punctured - you got a fire.

Because the charge controller likely does not run software that can easily be modified by the end user?

"When disagreeing, please reply to the argument instead of calling names. 'That is idiotic; 1 + 1 is 2, not 3' can be shortened to '1 + 1 is 2, not 3."

https://news.ycombinator.com/newsguidelines.html

I have multiple devices with lithium batteries plugged in 24/7. A kindle that I use as a display for example. So far nothing exploded. If exploding kindles were a thing I guess I would have heard.

The fact that they can doesn't mean they will.

On older devices the controller might make some assumptions that holds true with a new battery, but very much doesn't with an old and worn one.

My Macs have all been sensible about it, but I've seen Windows machines with batteries that just died from being plugged in all the time not even 10 years ago. Even if that specific instance was just a bad battery and not due to a charge controller, I have no faith in Random Windows or Android OEM Number 582 doing this correctly.

For devices that are fixed, I'd prefer to eliminate the potential of there even being a problem in the first place.

Three times I've been lazy and set up an old phone or tablet as an always-plugged-in stationary device without excising the battery, and that has produced two spicy pillows and one completely dead battery (phone wouldn't even boot when plugged in, until I replaced the battery). Granted, these were all 5-10 years ago, but I do not trust the batteries and their controllers in these devices.

Nowadays if I want to leave a device plugged in I crack it open, remove the battery cell, solder on a power supply and capacitor, and then do the nonsense with rooted Android to keep it from shutting itself down.

fwiw I’ve used 24/7/365 plugged in phones as AP’s in multiple locations for a decade or so now, never had an issue. Past few years I use the battery threshold to set them to 70% charge and they don’t move from this for months at a time.

What roasts the lifetime of my laptop batteries is compiling with gentoo, but again never an issue with catastrophic failure and I have 20+ years of experience with that as well.

I've gone through a dozen or so LiPo-utilizing portable devices at my property in the Mojave desert. All it takes is a single season for many of these batteries to swell up to such an extent the enclosures split open.

Ostensibly they contain charge controllers and temperature sensors, yet they're unable to prevent this outcome when the ambient temperature exceeds 110F day after day while the device stays on in a hot attic w/usb-c pd connected.

Fortunately I haven't had any burst into flames yet, but after a few years of seeing this pattern repeatedly I stopped deploying anything containing LiPo batteries at the property.

YMMV - but IMHO it's prudent to exclude these batteries from such unattended, powered 24x7 devices.

Most can, but you do get reports that sometimes they don't, and better safe than sorry.

I'd guess it would have more to do with heat, though.

That's silly. Batteries don't like to be kept at 100% all the time, not unlike your lungs which doesn't want to stay filled all the time (which is uncomfortable for your muscles even if you ignore the carbon dioxide).

e.g.: MacBooks discharge the battery down to 80% by using the battery even if it's plugged in by citing "Rarely used battery", and keep the battery at 80% for at least half a day, then charge it again.

Li-ion is an adversarial chemistry. You need to take care of it or the battery bites back by puffing up or losing capacity very fast, or becoming an indoor firework.

For how long?