Thanks! The biggest obstacle to running forever may be the chemistry of the li-poly battery which has a relatively low number of charge cycles and is known to degrade over time. A promising option is li-ion capacitors or supercapacitors, which I'm looking into. This is the board I've purchased for testing. https://www.tindie.com/products/jaspersikken/solar-harvestin...

Id just personally go with replaceable parts. AA NiMHs are like $1 to $2 these days, and 6V 5Ah lead acid is like $20 (Lol, first hit on google is $4 from some no-name brand).

Replace the battery every few years and you're set. Rely upon mass production, standard part numbers and highly recyclable parts (lead acid wins at this).

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Lead Acid is particularly good at UPS style power usage patterns. It's very easy to perpetually trickle charge lead acid.

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If you're set on Li-ion, then use a standard 18650 cell, so you know that you'll always be able to buy a replacement. But given the attributes I see here, lead acid probably wins. So you have to replace a part every 3 years that costs $5 to $10, big whoop.

No, no, no! This is the post-apocalypse laptop! You can’t go off buying new batteries in your mad-max car. It’s gotta work from that solar panel!

A post-apocalyptic backyard garage could conceivably recycle a lead-acid battery, they're pretty simple.

As it happens, I've spent a lot of time over the last week talking to a guy in Romania who's trying to fix a sulfated lead-acid battery in his backyard garage. (I don't know if you've been to Romania, but the apocalypse happened 40 years ago there, so his available resources are kind of limited.) I think he's going to succeed, and may eventually progress to being able to recycle the lead into a new battery, but it's not going to be a weekend learning process or even a week-long one.

He reports that it's a "very complex electrochemical device".

The USPTO (?) has assigned the code H01M10/06 to lead-acid battery patents. https://patents.google.com/?q=(H01M10%2f06)&oq=(H01M10%2f06) finds 44'593 patents in this category. You don't need any of them to get a working lead-acid battery, but a significant subset of them are going to be helpful. Some are order-of-magnitude improvements.

What kind of apocalypse happened in Romania 40 years ago?

I presume he's talking about the collapse of the Soviet Union, which caused a huge amount of upheaval in that area.

But I'm a poor student of modern history. Just throwing out a guess for now.

Right, but I got the time interval wrong; it was only 30 years ago.

Eventually it was good for Romania but IIRC, the initial collapse was very bad for the locals.

But again, I'd say that Eastern European modern history is my weakest subject by far. I probably should avoid talking about this subject lol.

And in a Mad-Max future (lots of cars around, but not enough fuel), there will be plenty of Lead Acid batteries laying around to recycle.

I do consider it effectively an apocalyptic kind of battery design. It was invented in the 1800s, its chemistry is incredibly simple (Sulfuric Acid + Lead), and is very well studied.

i prefer the phrase "anti-apocalyptic." Because by designing an energy efficient laptop/phone, less lithium/capacitor resources are manufactured and everyone can have one, unlike that single coke bottle in that 80s movie, "The Gods Must Be Crazy" which will lead to one. ;)

Would it be possible to use standard 9v rechargeable cells? I’m sure the lifetime would be even less, but if a battery swap cost $10 and could be found at any corner drug store…

You can look into LFP (aka LiFePo4) cells, which have higher durability than lithium ion. Beware they have different chemistry so charging voltages differ from standard Li-poly or Li-ion (they are also safer, which is nice). I haven't looked at the data, but I suspect supercaps may not be optimized for very low leakage, and generally the energy density is not so good (though if you have access to energy harvesting I guess it may not matter!).

Did you consider the possibility of using a FPGA Lisp CPU? [0] I hope the supercapacitor idea works and you don't have a leakage issue.

[0] https://frank-buss.de/lispcpu/

FPGA soft core CPUs can't beat the same logic implemented in ASIC silicon in terms of static power consumption. The MCU at the core of this project has a very impressive uA/MHz specification that's difficult to achieve alone. I'm surprised to see it being much lower than even STM32L0 running off external SMPS

> i love the minimalist concept of a laptop with so much battery life: Dell and Apple could learn something from this.

Really? What? Put on a tiny black and white display?? No backlight?? Tiny processor?? No SSD?? No HDD??

I mean, this is awesome. And look forward to see where it is going. Not sure what Dell and Apple will learn??

Dell and Apple can learn that there are consumers out there who want low cost minimalist options with long battery lives and long operational lives. Not everyone wants to buy a brand new 600$ computer every 5 years. They can learn that some consuemrs aren't going to put up with the crap of planned obsolescence.

Not really planned obsolescence, just lack of spare parts. 10 year old laptop will work just fine, it will just be hard to get replacement keyboard or batteries.

> Dell and Apple can learn that there are consumers out there who want low cost minimalist options with long battery lives and long operational lives.

They don't want their business and low marigin sales.

Also Macbook air has what, 18 hours of battery life ? That's enough for vast majority of users.

A MacBook has up to 18 hours when new, but you can get far less than that.

The real advantage of long battery life isn’t so much the duration when new but both reducing the number of charge cycles and preserving battery life as the device ages.

> They can learn that some consuemrs aren't going to put up with the crap of planned obsolescence.

The number of consumers who not only complain about planned obsolescence but also put money where their mouth is, is tiny. It's easy to get people on board with the idea behind projects like Fairphone, but then they do a price comparison and buy a cheap Huawei.

The market for Linux laptops is already a small niche and those aren't all that limiting for users when it comes to processing power and software support. Now take away the modern web browser and very few people would consider it for anything more than a little tinkering.

Unfortunately this is almost the least profitable market segment imaginable and isn't going to be addressed well by capitalism.

I don't mean this in a "capitalist bad" way, it's mostly great but there are certain innovations and technologies that don't fit well with a need to get the most return possible on capital invested. There's a "dead space" of techs that would benefit everyone, need some capital to create - but don't allow a lot of value to be captured.

A bit like how we see more VC excitement about "vat grown meat" (a centralised industrial model that exacerbates supply chain dependency and further alienates people from their food - but is perfect for capturing value) vs working on "super potatoes" or algae-based systems that would be low-dependency and could scale down to individuals.

Orthodoxy is that government is supposed to help with this stuff but they have their own incentives (some of them a result of industry capture) which rarely align with decentralisation, degrowth or reduced dependency. For example recent battles to get laws passed to even allow you to repair your own stuff.

It did address it fairly well. They were able to buy cheap, off-the-shelf components and build this with relatively little work.

If you had said that there are consumers who want long battery lives and long operation lives and are willing to pay a premium for that, then Dell and Apple might have something to learn - but the existence of consumers who want a low cost option for that is irrelevant, since serving that market would just lower your profits by cannibalizing your sales to the people who are not only willing to pay $600 every 5 years but $1000+ every 3 years.