There are a lot of things that get landfilled that have some marginal value, but generally if there’s not a huge amount of money to be made recycling things they won’t get recycled. It might not be surprising to most that this is true of almost all plastic, a substantial portion of glass, and even a lot of paper and metals, but what might come as a shock is that plenty of rechargeable lithium batteries are included in this list as well. It’s cheaper to build lithium batteries into one-time-use items like disposable vape pens and just throw them out after one (or less than one) charge cycle, but if you have some spare time these batteries are plenty useful.

[Chris Doel] found over a hundred disposable vape pens after a local music festival and collected them all to build into a battery powerful enough for an ebike. Granted, this involves a lot of work disassembling each vape which is full of some fairly toxic compounds and which also generally tend to have some sensitive electronics, but once each pen was disassembled the real work of building a battery gets going. He starts with testing each cell and charging them to the same voltage, grouping cells with similar internal resistances. From there he assembles them into a 48V pack with a battery management system and custom 3D printed cell holders to accommodate the wide range of cell sizes. A 3D printed enclosure with charge/discharge ports, a power switch, and a status display round out the build.

With the battery bank completed he straps it to his existing ebike and hits the trails, easily traveling 20 miles with barely any pedal input. These cells are only rated for 300 charge-discharge cycles which is on par for plenty of similar 18650 cells, making this an impressive build for essentially free materials minus the costs of filament, a few parts, and the sweat equity that went into sourcing the cells. If you want to take an ebike to the next level of low-cost, we’d recommend pairing this battery with the drivetrain from the Spin Cycle.\

Thanks to [Anton] for the tip!

https://www.youtube.com/watch?v=VcVp9T8f_W4

It is hard to imagine that much we built today will be used ten years from now, much less in a hundred. It is hard to make things that last through the ages, which is why we are fascinated with things like ancient pyramids in Mexico, Egypt, and China. However, even the oldest Egyptian pyramid is only about 5,000 years old. [Mark Piesing] at the BBC visited a site that is supposed to lock up nuclear waste for 100,000 years.

This particular project is in France, but there are apparently dozens of similar projects around the world. Locating these nuclear tombs is tricky. They need to be in a geologically stable area that won’t contaminate water. They also prefer areas already depleted of resources to lessen the chance someone will be digging nearby in the far future. You also need people to agree to have these facilities in their communities, which is probably the most difficult thing to find.

Burying anything 500 meters underground is a challenge. But we were interested in how you’d plan to keep the material safely away from people for 20 times longer than the pyramids have stood next to the Nile.  Anything could happen over that timescale, and it seems unlikely that you’ll have an organization that can last that long and stand watch over these dangerous vaults. If they poke around in these holes, future archeologists could deal with a very real cursed tomb.

Of course, the whole idea is controversial. But putting that aside, how would you design something to last 100,000 years and stay secure? Let us know in the comments. It would be good practice for that generation ship to Bernard’s Star.

We’ve seen that it is hard to keep a clock running for even 100 years. Already, 50-year-old computers seem incredibly antique. What will tech be like in 100,000 years?