Converting On-Grid Electronics To Off-Grid

May 11, 2023 by Dave Rowntree 54 Comments

Husband and wife team [Jason & Kara] hail from Canada, and in 2018, after building their own camper, sold up their remaining earthly goods and headed south. If you’re not aware of them, they documented their journey on their YouTube channel, showing many interesting skills and hacks along the way. The video we’re highlighting today shows a myriad of ways to power all the DC-consuming gadgets this they lug along with them.

LiFePO4 batteries are far superior to lead acid for mobile solar installations.

Their heavily modded F-550 truck houses 12kWh of LiFePO4 batteries and a 1.5kW retractable solar array, with a hefty inverter generating the needed AC power. They weren’t too happy with the conversion losses from piles of wall warts that all drained a little power, knowing that the inverter that fed them was also not 100% efficient. For example, a typical laptop power brick gets really hot in a short time, and that heat is waste. They decided to run as much as possible direct from the battery bank, through different DC-DC converter modules in an attempt to streamline the losses a little. Obviously, these are also not 100%

efficient, but keeping the load off the inverter (and thus reducing dependency upon it, in the event of another failure) should help stem the losses a little. After all as [Jason] says, Watts saved are Watts earned, and all the little lossy loads add up to a considerable parasitic drain.

One illustration of this is their Starlink satellite internet system consumes about 60W when running from the inverter, but only 28W when running direct from DC. Over the course of 24 hours, that’s not far off 1kWh of savings, and if the sun isn’t shining, then that 12kWh battery isn’t going to stretch as far.

There are far too many hacks, tips, and illustrations of neat space and power-saving solutions everywhere, to write here. Those interested in self-build campers or hacking a commercial unit may pick up a trick or two.

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A black and white image of the Sun and Earth with a series of lines radiating out from the sun and bisecting rings circumscribed around it. On the Earth are three dots with the text "Active Server" on one exposed to the Sun and two dots representing "Inactive Server"s on the dark side.

Solar Protocol Envisions A Solar-Powered Web

April 21, 2023 by Navarre Bartz 34 Comments

The transition to low carbon energy is an important part of mitigating climate change, and the faster we can manage, the better. One project looking at how we could reduce the energy requirements of the web to more quickly adopt renewable energy is Solar Protocol.

Instead of routing requests to the fastest server when a user pulls up a website, Solar Protocol routes the request to the server currently generating the greatest amount of solar power. Once a user is on a website, the experience is energy-responsive. Website style and image resolution can range based on the power left in the active server’s batteries, including an image free low power mode.

Another benefit to the project’s energy efficiency approach is a focus on only the essential parts of a page and not any of the tracking or other privacy-endangering superfluous features present on many other websites. They go into much more depth in the Solar Protocol Manifesto. As a community project, Solar Protocol is still looking for more stewards since the network can go down if an insufficient number of servers are generating electricity.

For more details on the project that inspired Solar Protocol, check out this low-tech website.

New Renewable Energy Projects Are Overwhelming US Grids

April 17, 2023 by Lewin Day 239 Comments

It’s been clear for a long time that the world has to move away from fossil energy sources. Decades ago, this seemed impractical, when renewable energy was hugely expensive, and we were yet to see much impact on the ground from climate change. Meanwhile, prices for solar and wind installations have come down immensely, which helps a lot.

However, there’s a new problem. Power grids across the US simply can’t keep up with the rapid pace of new renewable installations. It’s a frustrating issue, but not an insurmountable one.

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Screenshot from the presentation, showing the datalogger product image next to the datalogger specs stated. The specs are suspiciously similar to those of a Raspberry Pi 3.

Reclaiming A Pi-Based Solar Datalogger

March 4, 2023 by Arya Voronova 7 Comments

There’s quite a few devices on the market that contain a Raspberry Pi as their core, and after becoming a proud owner of a solar roof, [Paolo Bonzini] has found himself with an Entrade ENR-DTLA04DN datalogger which – let’s just say, it had some of the signs, and at FOSDEM 2023, he told us all about it. Installed under the promise of local-only logging, the datalogger gave away its nature with a Raspberry Pi logo-emblazoned power brick, a spec sheet identical to that of a Pi 3, and a MAC address belonging to the Raspberry Pi Foundation. That spec sheet also mentioned a MicroSD card – which eventually died, prompting [Paolo] to take the cover off. He dumped the faulty SD card, then replaced it – and put his own SSH keys on the device while at it.

At this point, Entrade no longer offered devices with local logging, only the option of cloud logging – free, but only for five years, clearly not an option if you like your home cloud-free; the local logging was not flawless either, and thus, the device was worth exploring. A quick peek at the filesystem netted him two large statically-compiled binaries, and strace gave him a way to snoop on RS485 communications between the datalogger and the solar roof-paired inverter. Next, he dug into the binaries, collecting information on how this device did its work. Previously, he found that the device provided an undocumented API over HTTP while connected to his network, and comparing the API’s workings to the data inside the binary netted him some good results – but not enough.

The main binary was identified to be Go code, and [Paolo] shows us a walkthrough on how to reverse-engineer such binaries in radare2, with a small collection of tricks to boot – for instance, grepping the output of strings for GitHub URLs in order to find out the libraries being used. In the end, having reverse-engineered the protocol, he fully rewrote the software, without the annoying bugs of the previous one, and integrated it into his home MQTT network powered by HomeAssistant. As a bonus, he also shows us the datalogger’s main PCB, which turned out to be a peculiar creation – not to spoil the surprise!

We imagine this research isn’t just useful for when you face a similar datalogger’s death, but is also quite handy for those who find themselves at the mercy of the pseudo-free cloud logging plan and would like to opt out. Solar tech seems to be an area where Raspberry Pi boards and proprietary interfaces aren’t uncommon, which is why we see hackers reverse-engineer solar power-related devices – for instance, check out this exploration of a solar inverter’s proprietary protocol to get data out of it, or reverse-engineering an end-of-life decommissioned but perfectly healthy solar inverter’s software to get the service menu password.

Solar Cell Fabric Makes Anything Solar

December 18, 2022 by Al Williams 16 Comments

MIT has been working on very thin solar cells made of a film just a few microns thick. The problem? The cells are so thin that they’re hard to work with. You could make a small solar cell on top of, say, a glass slide, but that’s not all that interesting since you can make perfectly good solar cells that are as fragile as glass using conventional techniques. But in a new paper, MIT researchers describe creating 50-micron-thin fabrics that can generate electricity from solar.

The process still involves using chemical vapor deposition to produce the solar cell on glass. However, the cells are removed from the glass, prepared with electrodes, and then transferred to a piece of fabric which acts as a new substrate.

The fabric used in the paper is a composite fabric known as Dyneema composite fabric. It uses ultra-high molecular weight polyethylene fibers and sheets of Mylar. This material has low weight but a very high strength. A UV cure adhesive bonds the fabric and solar cells.

Honestly, we doubt anyone will be making these in their garages anytime soon. But we would love to see what you could do with a roll of this fabric. Wearables, self-charging laptop bags, or solar-powered instruments in an airborne drone could all take advantage of the material’s flexibility and low weight.

Smelting Solar Style

November 7, 2022 by Al Williams 32 Comments

If you attended the 2022 Supercon, you might have heard the story about the SMD soldering challenge table nearly catching on fire. A magnifying lamp caught the sun just right and burned a neat trench into another lamp’s plastic base. While disaster was averted, [Jelle Seegers] does this on purpose using a huge 5-meter lens to smelt metal.

The Design Academy Eindhoven student is participating in Dutch Design Week and built the machine which is able to manually track the sun to maximize the amount of solar energy applied to the metal.

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Comparing Solar Energy Harvesters

October 27, 2022 by Bryan Cockfield 11 Comments

There doesn’t have to be much more to setting up a simple solar panel installation than connecting the panel to a battery. Of course we would at least recommend the use of a battery management system or charge controller to avoid damaging the battery, although in a pinch it’s not always strictly necessary. But these simple systems leave a lot on the table, and most people with any sizable amount of solar panels tend to use a maximum power point tracking (MPPT) system to increase the yield of the panels. For a really tiny installation like [Salvatore] has, you’ll want to take a look at a similar system known as a solar energy harvester.

[Salvatore] is planning to use an energy harvester at his small weather station, which is currently powered by an LDO regulator and a small solar cell. While this is fairly energy efficient, the energy harvesters that he is testing with this build will go far beyond what an LDO is capable of. The circuit actually has two energy harvesters built onto it which allows him to test the capabilities of both before he makes a decision for his weather station. Every amount of energy is critical when using the cell he has on hand, which easily fits in the palm of one’s hand.

The testing of this module isn’t complete yet, but he does have two working prototypes to test in future videos to see which one truly performs the best. For a project of this size, this is a great way to get around the problem of supplying a small amount of power to something remote. For a larger solar panel installation, you’ll definitely want to build an MPPT system though.

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