[megaman8]

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

so that gray piece on the right is the solar collector, right? since it can go 2 years, what's to stop it from going forever? what if you added a 2nd collector on the left? how big would the solar panel need to be in order for it to run indefinitely?

Super job!

[reerdna]

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...

[dragontamer]

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.

[TylerE]

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…

[gnramires]

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!).

[mycall]

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/

[megablast]

> 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??

[megaman8]

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.