perestroika

@perestroika@slrpnk.net

• ⁨Comment⁩ on ⁨Will solar panels overrun farmland? The two are more likely to coexist.⁩ ⁨⁨5⁩ ⁨days⁩ ago⁩:

  Indeed, vertical solar panels are fully compatible with farming. :) And it’s also smart to position them north-south, to get on the market on morning and evening hours - because midday is already “crowded” by conventional solar parks.

  Also, vertical panels are more resistant to hail.

• ⁨Comment⁩ on ⁨First sodium battery urban e-bike offers 45-mile range and operates in cold weather without capacity loss⁩ ⁨⁨2⁩ ⁨weeks⁩ ago⁩:

  A big advantage of its sodium cells is also the fact that they can retain more than 92% of their capacity even when operating at -20°C (-4 Fahrenheit) and discharging at those freezing temps.

  That is very promising to hear. My current vehicle, which uses first-generation lithium batteries (made on 2011), loses almost half of its range at that temperature, and that is before heating.

• ⁨Comment⁩ on ⁨Homebrew battery⁩ ⁨⁨2⁩ ⁨weeks⁩ ago⁩:

  Nice to know. :)

  The comment from the reader John Beech (an old radio amateur) at the bottom is probably of greater practical value: he describes how he developed DIY cells to the point of running a 2 W radio.

  Another way to build DIY batteries is using the iron-air chemical combination. A decent collection of recipes can be found here, using filter cartridges of activated carbon as cathodes and rebar wrapped in steel wool as anodes.

  instructables.com/Create-large-refuelable-metal-a…

• ⁨Comment⁩ on ⁨Trump Says He Wants No Wind Turbines Built During Administration⁩ ⁨⁨3⁩ ⁨weeks⁩ ago⁩:

  Some gusses:

  • Vanity and spite. After all, he’s not emotionally mature.

  • With some probability, he’s seeking attention from his supporters and needs to satisfy lobbyists who bought and propagandized his way to power. He has to deliver them goods. This is how he shows that he intends to deliver the goods… that he actually cannot deliver without changing the constitutional order very much.

  • Maybe he wants to test the mettle of the terrible Renewable Industries Complex - an industry very prone to organizing coups and hiring assassins. If I were him, I’d consider twice, all the people in the solar business that I know have been extremely menacing. ;P ;P ;P

• ⁨Comment⁩ on ⁨Dark Doldrums Overshadow Europe’s Energy Markets | Periods of low sun and wind, a weather pattern known as a Dunkelflaute, can increase electricity prices and stoke political tensions.⁩ ⁨⁨4⁩ ⁨weeks⁩ ago⁩:

  It seems that weather patterns lasting longer is part of the new climate pattern.

• ⁨Comment⁩ on ⁨Sol-Ark manufacturer reportedly disables all Deye inverters in the US⁩ ⁨⁨2⁩ ⁨months⁩ ago⁩:

  Oh, indeed, that’s a common problem with them. :)

  You can find them here:

  maximumsolar.online

• ⁨Comment⁩ on ⁨Sol-Ark manufacturer reportedly disables all Deye inverters in the US⁩ ⁨⁨2⁩ ⁨months⁩ ago⁩:

  My preference has become Maximum Solar. They work well enough with button and LCD control.

  I reprogram them twice a year when transitioning between summer modes (hot, energy surplus, preserve batteries by not charging them fully) and winter modes (cold, energy deficit, fill batteries to the maximum). I’ve thought about automating that, but didn’t bother.

• ⁨Comment⁩ on ⁨Sol-Ark manufacturer reportedly disables all Deye inverters in the US⁩ ⁨⁨2⁩ ⁨months⁩ ago⁩:

  I never let my energy devices onto the Internet. The house controller - a Raspberry Pi - is allowed when I wire it to the router using an ethernet cable.

  If I worjed at the company which did the cyberattack, I would fear both civil liability and prosecution.

• ⁨Comment⁩ on ⁨Howto build 8-bit breadboard computer⁩ ⁨⁨2⁩ ⁨months⁩ ago⁩:

  Very very impressive. :)

• ⁨Comment⁩ on ⁨Vertical solar panels help farmers produce both energy and crops⁩ ⁨⁨3⁩ ⁨months⁩ ago⁩:

  Machinery comes is varying width. I would guess a farmer needs to decide at some point - is the priority using a 10-meter wide tool, or is it OK to settle with a 6-meter tool, or even a smaller one.

  Basing on that, they’ll decide what the clearance between rows of panels should be. From an energy installation viewpoint, the shadow of one row should not cover another row during normal operating conditions. Assuming sun at 30 degrees elevation (“September on latitude 60”), the shadow of a fence that’s 1.2 meters tall will be about 1.75 * 1.2 = 2.1 m long. So from an energy generation viewpoint, one can pack things more densely than makes sense for farming.

• ⁨Comment⁩ on ⁨Solar panels between railway tracks?⁩ ⁨⁨3⁩ ⁨months⁩ ago⁩:

  Also, costing €623,000 over three years sounds rather expensive for just 100m

  It’s hugely expensive, but I expect most of the cost to be in the wagon that lays panels down and picks them up.

  I doubt if this project will “fly”, however. A totally horizontal solar panel at ground level is a far cry from producing energy efficiently.

• ⁨Comment⁩ on ⁨solar PV → heat pump → water heater; direct, no A/C or intermediate components. Practical? Feasible?⁩ ⁨⁨4⁩ ⁨months⁩ ago⁩:

  P.S. I have once used DC to power a pump “directly”. I use quotation marks because the pump (a water pump) was a brushless DC motor with an integrated controller. I used it on a field for removing water after a spring flood. Its controller accepted 24…48 V input, and it was powered from a 40 V solar panel brought on a wheelbarrow. :)

• ⁨Comment⁩ on ⁨solar PV → heat pump → water heater; direct, no A/C or intermediate components. Practical? Feasible?⁩ ⁨⁨4⁩ ⁨months⁩ ago⁩:

  instead of powering the heat pump from the wall, the heat pump can be connected directly to a PV

  I have no experience with this exact combination. I know that “batteryless” inverters exist, but most of them are on-grid inverters. In that scenario, all that matters is monitoring your production: if you don’t want grid energy, you only run your system when your PV produces enough.

  Another type of batteryless inverters are “pump inverters”. Farmers seem to like them for pumping water from wells into water towers. A pump inverter can be configured to run at 50 Hz (or 60 Hz for North Americans) and 230…240 V alright, but it is not designed to power electronic devices, but dumb agricultural motors. There is considerable risk involved with powering a heat pump from a pump inverter, unless you find an exceptionally simple and dumb heat pump with very limited or resilient steering electronics.

  Efficiency losses are small anyway, but mostly happen during battery storage or when voltage needs to rise or drop considerably (e.g. a transition of 700 -> 24 V or 24 -> 240 V would cause a small efficiency loss).

  I’ve heard that a PV can directly power a compressor

  This seems unlikely as the compressor would have to be a brushed DC motor. That kind of motors don’t last long, they wear out their brushes. But a brushless DC motor is essentially a three-phased AC motor already, just the controller (full of smartness and MOSFET transistors) accepts DC input.

  If you have a good technical overview of your heat pump system, maybe you can locate a point where regulated DC can be fed into the system, but that would be hacking. Alternatively, maybe a niche market already exists for DC-powered heat pumps, e.g. for caravans, trucks or ships? But on niche markets, prices typically aren’t good for you. :(

• ⁨Comment⁩ on ⁨Swiss Researchers May Have Solved Hydrogen Storage⁩ ⁨⁨4⁩ ⁨months⁩ ago⁩:

  it would (as far as i understand with high school chemistry) be strictly more efficient to electrolyse rust directly

  I’m not a chemist either, but I do know a bit of chemistry.

  Typically, you need a solution of NaOH (sodium hydroxide) to directly reduce iron oxide in an electrolysis cell. If your iron oxide contains impurities, those may react with NaOH and ruin the fun. Also, if you have exposure to CO2, your NaOH will gradually [degrade]www.aqion.de/site/182), producing NaHCO3.

• ⁨Comment⁩ on ⁨Exclusive: Sodium batteries to disrupt energy storage market | Oliver Gordon | July 1, 2024⁩ ⁨⁨5⁩ ⁨months⁩ ago⁩:

  Well, for a chance - they are now actually in production, while 5 years ago they were in laboratories.

• ⁨Comment⁩ on ⁨Solar leading Baltic states to energy security⁩ ⁨⁨6⁩ ⁨months⁩ ago⁩:

  Out of the three, Latvia has serious energy storage - a 4 billion cubic meter (at normal pressure) underground gas store, sufficient to carry all three countries over the winter.

  But so far, it’s filled with fossil natural gas - but some day it could be filled with synthesized methane.

  As a backup option, Estonia has oil shale - probably the worst fuel on Earth, so the price of emitting CO2 keeps those plants out of the energy market during summer. During winter, they come online though.

  As for solar, we aren’t planning to rely much on that. Solar capacity has of course skyrocketed, but only because it’s very easy to install. But at latitudes 55 to 60, days are really very short in midwinter, so wind and waste wood are the likely candidates in future - after oil shale leaves the scene, but before synthetic gas becomes feasible.

  Regarding pumped hydro - it can stabilize a day, but can’t stabilize a week or month. Lithuania has a biggish (~10 GWh) pumped storage facility. The rest of Baltics don’t have suitable terrain. Estonia has limestone banks, but they’re under various forms of protection and even if one built a lot of pumped hydro, the low elevation difference (up to 50 meters) means one couldn’t support the electric grid through more than a few days.

  Regarding hydrogen - maybe.

• ⁨Comment⁩ on ⁨The Raspberry Pi 5 is no match for a tini-mini-micro PC⁩ ⁨⁨7⁩ ⁨months⁩ ago⁩:

  I would add:

  • if you wanted direct and low-latency access to cameras (for machine vision)
• ⁨Comment⁩ on ⁨Don't let people sell you flashlights :)⁩ ⁨⁨8⁩ ⁨months⁩ ago⁩:

  It sure is.

  A typical “obscenely bright” LED chip might be Cree XML, but many similar chips exist. Then you need a driver. Some are fixed while some adjustable with a tiny potentiometer. You’d need an 18650 cell holder (it can be made too, an 18650 will go into a leftover piece of 20 mm electrical cabling pipe with a spring-loaded metal cap engineered of something).

  Myself, I bought a nice head lamp, but it broke after one year. The driver board failed. Being of the lazy variety, I replaced the board with a resistor to limit current and now it’s been working 3 years already. Not at peak luminosity, the resistor wasn’t optimal of course. :)

• Don't let people sell you flashlights :)slrpnk.net ↗
  Submitted ⁨⁨8⁩ ⁨months⁩ ago⁩ to ⁨diy@slrpnk.net⁩ | ⁨8⁩ ⁨comments⁩
• ⁨Comment⁩ on ⁨ZFS High Availability with Asynchronous Replication and zrep⁩ ⁨⁨8⁩ ⁨months⁩ ago⁩:

  Thanks, that looks like something I might have to try. :) Myself, over the network, I still don’t do filesystem level incremental backups, sticking to either directories or virtual machine snapshots (both of which have their shortcomings).

• ⁨Comment⁩ on ⁨ZFS High Availability with Asynchronous Replication and zrep⁩ ⁨⁨8⁩ ⁨months⁩ ago⁩:

  I’ve been hearing about ZFS and its beneficial features for years now, but mainstream Linux installers don’t seem to support it.

  Out of curiosity - can anyone tell, what might be blocking them?

• ⁨Comment⁩ on ⁨Raspberry Pi 5 vs Intel N100 mini PC comparison - Features, Benchmarks, and Price⁩ ⁨⁨8⁩ ⁨months⁩ ago⁩:

  From a person who builds robots, three notes:

  1. Camera

  Raspberry Pi has two CSI (camera serial interface) connectors on board, which is a considerable advantage over having to deal with USB webcams. This matters if your industrial robot must see the work area faster, your competition robot must run circles around opposing robots, or more sadly - if your drone must fly to war. :( On Raspberry Pi, in laboratory conditions, you can access the camera (with big ifs and buts) at 500+ frames per second. That’s impossible over USB and unheard of to most USB camera makers.

  2. Optimized libraries

  I know that Raspberry Pi has “WiringPi” (a fast C library for low level comms, helping abstract away difficult problems like hardware timing, DMA and interrupts) and Orange Pi recently got “WiringOP”. I don’t know of anything similar on a PC platform, so I believe that on NUC, you’d have to roll your own (a massive pain) or be limited to kilohertz GPIO access frequencies instead of megahertz.

  3. Antenna socket

  Sadly, neither of them has a WiFi antenna socket. But the built-in WiFi cards are generally crappy too, so if you needed a considerable working area, you’d connect an external card with an external antenna anyway. Notably, some models of Orange Pi have an external antenna, and the Raspberry Pi Compute Module has one too.

• ⁨Comment⁩ on ⁨Fifty Things you can do with a Software Defined Radio 📻⁩ ⁨⁨10⁩ ⁨months⁩ ago⁩:

  I’m inclined to add:

  51: monitor the radio spectrum for drones (and if they are hostile, warn people about them) - there’s a DIY recipe for a monitoring station out there somewhere, and some Ukrainian guys scan their sky with HackRF

  SDR is definitely a technology worth learning.

• ⁨Comment⁩ on ⁨What's Up?⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  Trying to figure out how my heat pump supposedly supports WiFi… in unfathomable and non-standard ways. It’s available as an access point, I can associate and ping it, but no TCP ports listen and no UDP port responds. Nothing cool, undocumented features down to the rocky bottom. When you buy a heat pump and plan to automate its use, check out supported protocols before making a decision. :)

• ⁨Comment⁩ on ⁨Gravity Storage 101 Or Why Pumped Hydro Is The Only Remotely Real Gravity Storage⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  Yep. As for why:

  • the material being raised and lowered must be very cheap (to be able to afford much of it)
  • the material must be possible to automatically handle in arbitrary amounts
  • the friction of raising / lowering the material must be low
  • the handling should not require a slope of particular grade or a specific height

  Trains fail the cheapness and arbitrary amount check, along with the slope grade check. Sand fails the friction check. Concrete blocks are close to failing the cheapness and arbitrary amount check. Cranes fail the specific height check for certain ranges of height.

  Water… it also requires a certain slope grade, but the range is not narrow.

• ⁨Comment⁩ on ⁨Scientist Discover How to Convert CO2 into Powder That Can Be Stored for Decades⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  Looks sound, but I’m not qualified to say if success will follow:

  en.wikipedia.org/wiki/Sodium_formate

  Upon modest heating, sodium formate decomposes into hydrogen and sodium oxalate. Shipping that somewhere where it gets converted back to sodium formate is the tricky part, because that seems unlikely to happen onsite (on a small site, anyway).

• ⁨Comment⁩ on ⁨€45,000 for a heat pump installation in Germany -- really?⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  Why does the title link point to a BBC story about South Africa? :)

  To answer the question - I don’t know.

  For comparison: installing an air-to-air heat pump for a tiny house in Estonia:

  • heat pump unit (smallest unit, maybe 3 KW heat output for 1 KW electrical input), bought at the deepest discount: 450 €
  • physical installation (mounting on a rack on a wall) - DIY, 0 €
  • electrical installation (running a cable to the outer unit and back to the inner from there) - DIY, 0 €
  • sealing and letting the working fluid into pipes - technician’s visit, 100 €

  I would imagine that an air-to-water unit costs more (the cheapest are probably over 1000 €, unless you use a pool heat pump which can be crappy), that an average German family lives in a far bigger house (so maybe 3 x more wattage), and that they need 3 installation technicians for several hours (maybe 1500 €).

  Beyond that - profit?

• Dieselgate, but for trains – some heavyweight hardware hackingbadcyber.com ↗
  Submitted ⁨⁨1⁩ ⁨year⁩ ago⁩ to ⁨fixing@slrpnk.net⁩ | ⁨1⁩ ⁨comment⁩
• ⁨Comment⁩ on ⁨Not All Batteries are Created Equal | Hackaday.io⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  Unfortunately, yes.

  I’ve had multipe experiences with seeing a flashlight battery which, according to labels, ought to have the capacity of an electric vehicle cell. And of course they don’t. :)

  If one needs high current, measuring the current with a known and low resistance (e.g. car headlight bulb) helps.

• ⁨Comment⁩ on ⁨Solar module prices may drop 40% to $0.10/W by end 2024⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  As an anecdote, I can tell that I’m still using my shattered solar panels. :)

  (Normal people would not, of course.)

  One broke during welding because a droplet of molten metal hit it - the hardened glass shattered all over. Another met with a flying plywood sheet during a storm - the plywood went right through with a corner and made a hole.

  I use both panels on a wheelbarrow to pump water on the field during flood season. They’re perfect, nobody wants to steal them because they look like they got nuked. :D I worry about the wheelbarrow considerably more. :D

  But yes, a recycling plan would be needed. Grinding them up and getting the aluminum back is not too hard, but how to separate the glass from the sealing silicone and doped silicon - I know some folks in Korea do it, but I don’t know how. :o