I have a 100 W rigid solar panel including a charge controller that I currently only use for camping to charge batteries (also useful in an emergency at home). It strikes me as a waste that I could be generating more clean energy with equipment that I already have, but I don't have anything in mind to use this energy for.

Obviously I could try to tie it into my home to run more of my household on solar, or buy more/bigger batteries to charge, but with 100 W of generation, it's probably not worth it without a significantly increased investment.

I tried searching around online, and I found plenty of discussion for what to do with a whole house that generates excess capacity (mainly sell to the grid), but nothing really on what to do with small scale DC generation.

Anyone here have thoughts?

I can't remember if I saw the argument here or on Reddit, but this is my preferred platform so it's going here.

Summary of argument: a user should have been using water for their thermal battery, not sand, because water has better heat capacity (4.18 joules per unit of mass person unit heat - 4.18/gK). Sand's thermal capacity is significantly lower (0.835J/gK).

Looking at these numbers alone in the post I understood why someone would say that; it also made me question why so much research is being done on sand batteries. The user who argued against sand batteries missed a crucial factor: material density. Water has a density of 1000kg per m^3. Dry sand (regular not pure quartz sand) has a density of 1730 kg per m^3. I found no satisfactry response to the argument in that thread, but that thread is now lost to me. I have also been curious about how much better regular sand is for heat batteries than water.

When designing large batteries, the goal is usually energy per volume. Let's compare 1m^3 of each (roughly 3.3ft cube) and how much heat it can hold before the next state change (which matters a lot when managing the pressure from steam).

Total stored energy = mass (g) * thermal capacity (J/gK) * heat (kelvin).

Water: 1,000,000 * 4.18 * 373.15 = 1,559,767,000J Sand: 1,730,000 * 0.835 * 1996.15 = 2,883,538,482.5J

Over 1 billion more joules per m^3. I hope this makes it clearer why sand batteries are such an area of interest lately. It certainly did to me.

Disclaimer: I am not an expert, so there may be mistakes. All the numbers and relevant equations were found on the internet.

I've always been fascinated by these small computers. GPD makes these kinds of devices too. Ordered one once but I never got it. Been thinking of building one myself though I'm worried it would be too small to enjoyable use. I would definitely write on it, that I am sure of.

a cool video i think is tagnentially related to solarpunk meows!

robots get workers rights too for betterment of all!!

Kind of curious what tech people own, everything from small to big tech. Assuming solarpanels are a given for a lot of peeps here, or maybe will be in the future. But what other tech do you own that you're happy with?

This is an industrial designed exercise bike from Lithuania that can store 2KWh of electricity generated by your own exercise.

It's so rare to actually see a new battery tech exit the lab and enter production. Always seems like there's 10,000 new up and coming breakthroughs in battery technology, but none ever leave the workbench.

While Na-ion batteries don't have the energy density of Li-ion, they make up for it with many other factors such as more abundant source materials, increased safety, higher charge/discharge currents, and increased number of charge cycles.

Slashdot summary:

Not only is sodium somewhere between 500 to 1,000 times more abundant than lithium on the planet we call Earth, sourcing it doesn't necessitate the same type of earth-scarring extraction. Even moving beyond the sodium vs lithium surname comparison, Natron says its sodium-ion batteries are made entirely from abundantly available commodity materials that also include aluminum, iron and manganese. Furthermore, the materials for Natron's sodium-ion chemistry can be procured through a reliable US-based domestic supply chain free from geopolitical disruption. The same cannot be said for common lithium-ion materials like cobalt and nickel.

Sodium-ion tech has received heightened interest in recent years as a more reliable, potentially cheaper energy storage medium. While its energy density lags behind lithium-ion, advantages such as faster cycling, longer lifespan and safer, non-flammable end use have made sodium-ion an attractive alternative, especially for stationary uses like data center and EV charger backup storage. [...] Natron says its batteries charge and discharge at rates 10 times faster than lithium-ion, a level of immediate charge/discharge capability that makes the batteries a prime contender for the ups and downs of backup power storage. Also helping in that use case is an estimated lifespan of 50,000 cycles.

I found these kind of cool as an idea, as they can be added rather easily to existing cities and provide some greenery without taking up space, while providing shade:

https://www.singulargreen.com/en/green-shades-valladolid/

A good overview and link collection around small scale hydro power technologies

I was watchin the last episode of ''earthsounds'' (docuseries that you can find on torrent) and they said to have used one of this with a microphone mounted under it to record better sounds from whales (because they travel a looooooot and not always on the same routes).

Autonomous robot solarpowered to catch better ocean data, pretty solarpunk to me :3

p.s. the series is nice even tho first 4 episodes have much more cool sounds; it's also interesting to see how hard it is to capture the sounds at the end of every episode

p.p.s. ye, it's not open source, by a company owned by boeing and probably also used for militar purposes so it's not perfectly as we would like it to be

💩 tech! On a serious note, this was in my random recommends and I clicked it and now I know about something I had no idea even existed. If this technology can come to fruition, it'll be great for the world.

This is quite exciting in that it removes plastic waste. I see no reason why different companies can't make different shape ones to maintain their lock-in. I expect a knock-off market to pop-up, but that exists with plastic pods too. It's a step in the right direction at least.