Microbatteries On The Grid

Not everybody has $6500 to toss into a Tesla Powerwall (and that’s a low estimate), but if you want the benefits of battery storage for your house, [Matt]’s modular “microbattery” storage system might be right up your alley. With a build-as-you-go model, virtually any battery can be placed on the grid in order to start storing power from a small solar installation or other power source.

The system works how any other battery installation would work. When demand is high, a series of microinverters turn on and deliver power to the grid. When demand is low, the batteries get charged. The major difference between this setup and a consumer-grade system is that this system is highly modular and each module is networked together to improve the efficiency of the overall system. Its all tied together with a Raspberry Pi that manages the entire setup.

While all of the software is available to set this up, it should go without saying that working with mains power is dangerous, besides the fact that you’ll need inverters capable of matching phase angle with the grid, a meter that handles reverse power flow, a power company that is willing to take the power, and a number of building code statutes to appease. If you don’t have all that together, you might want to go off-grid instead.

Restoring The Coolest Laptop Ever

Well-seasoned readers will no doubt remember GRiD laptops, the once and always tacti-cool computers that dominated the military market for decades. GRiDs were the first laptops to go to space, and they were coveted for their sleek (for the time) good looks and reputation as indestructible machines.

The GRiDs went through many iterations, and even though their military roots make them nearly unobtanium, [Simon] scored a GRiD laptop and set about restoring it. His theme was the 1986 movie Aliens, which featured a few GRiD Compass computers as props. [Simon]’s 1550SX came a little later than the Compass 2, but documents with the machine reveal it was a Royal Air Force machine that had been deemed unserviceable for reasons unknown.

[Simon] carefully tore it down – pay close attention to the video below and you’ll hear the telltale plink of the magnesium case parts rather than the dull thud of plastic; they don’t make them like that anymore – and cleaned it up. He replaced the original display with a PiMoroni 10″ retro game display to keep the original 4:3 aspect ratio. A Raspberry Pi 4 went inside, along with a Teensy to take care of adapting the GRiD keyboard to USB and lighting up some front-panel LEDs. A second Teeny allows the original IsoPoint mouse to be used, which is a real gem. With the addition of appropriate graphics, the machine looks like it would be at home on a Colonial Marines dropship.

We love the retro feel of [Simon]’s build, and the movie nostalgia. We’re just glad he didn’t include a LiPo battery, which might not get along with the magnesium case. Game over, man!

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How The Power Gets To The Outlet

[Practical Engineering] is ready to explain how power substations get electricity to you in his latest video, which you can see below.  One of the things we always notice when talking to people either in our community or outside it is that most people have no idea how most of the modern world works.

Ask your non-technical friend to explain how a cell phone works or how a hard drive stores data and you aren’t likely to get a very good answer. However, even most of us are only focused on some particular aspect of electronics. There are a lot of people who hack on robots or radios. The AC power grid,though isn’t something a lot of people work with as a hobby. Do you know exactly what goes on in that substation you pass every day on your commute? If you don’t, you’ll learn something in the video.

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A Field Guide To Transmission Lines

The power grid is a complicated beast, regardless of where you live. Power plants have to send energy to all of their clients at a constant frequency and voltage (regardless of the demand at any one time), and to do that they need a wide array of equipment. From transformers and voltage regulators to line reactors and capacitors, breakers and fuses, and solid-state and specialized mechanical relays, almost every branch of engineering can be found in the power grid. Of course, we shouldn’t leave out the most obvious part of the grid: the wires that actually form the grid itself.

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A Peek Inside A Typical British Residential Power Panel

No matter what field you’re in, it’s interesting and instructive to find out how others practice it. That’s especially true with electrical distribution systems, where standards and practices differ from country to country and even between regions. This tour of a typical British residential electrical panel is a great example of the different ways that the same engineering problems can be solved, and the compromises that always attend any design.

We’re used to seeing [Big Clive] tearing interesting devices to bits, but rest assured that this electrical panel remains largely intact as it gives up its secrets. Compared to the distribution panels and circuit breakers common in North American residential construction, the British consumer unit is a marvel of neatness and simplicity. True, the unit on display hasn’t been put into service yet, and things will no doubt change once an electrician is through with it, but the fact that everything is DIN rail mounted is pretty cool. [Clive] explains a few of the quirks of the panel, such as the fact that what looks like a main breaker is in fact just an isolation switch, and that there are a pair of residual current devices (RCDs), which we call ground-fault circuit interrupters (GFCIs) in North America, that also don’t act as circuit breakers, despite appearances. A stout bus bar is provided to link the RCDs to adjacent circuit breakers, forming two groups that are separately protected from ground faults.

[Clive] notes with dismay that the lugs of the bus bar can actually be inserted behind the rising clamp terminal on the breaker, resulting in poor connections and overheating. Still, we wouldn’t mind some of these concepts brought to panels in North America, which we covered a bit in a discussion on circuit protection a while back.

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Adventures In Power Outage Hacking

The best type of power outage is no power outage, but they will inevitably happen. When they do, a hacker with a house full of stuff and a head full of ideas is often the person of the hour. Or the day, or perhaps the week, should the outage last long past the fun little adventure phase and become a nuisance or even an outright emergency.

Such was the position that [FFcossag] found himself in at the beginning of January, when a freak storm knocked out power to his community on a remote island in the middle of the Baltic Sea. [FFcossag] documented his attempts to survive the eight-day outage in vlog form, and although each entry is fairly long, there’s a lot to be learned from his ordeal. His main asset was a wood cook stove in the basement of the house, which served as his heat source. He used a car radiator and a small water pump to get some heat upstairs – a battery bank provided the power for that, at least for a while. The system evolved over the outage and became surprisingly good at keeping the upstairs warm.

The power eventually came back on, but to add insult to injury, almost as soon as it did, the ground-source heat pump in the house went on the fritz. A little sleuthing revealed an open power resistor in the heat pump control panel, but without a replacement on hand, [FFcossag] improvised. Parts from a 30-year-old TV transmitter were close at hand, including a nice handful of power resistors. A small parallel network gave the correct value and the heat pump came back online.

All in all, it was a long, cold week for [FFcossag], but he probably fared better than his neighbors. Want to be as prepared for your next outage? Check out [Jenny]’s comprehensive guide.

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A Look At Liquid Dielectrics

One evening quite a few years ago, as I was driving through my hometown I saw the telltale flashing lights of the local volunteer fire department ahead. I passed by a side road where all the activity was: a utility pole on fire. I could see smoke and flames shooting from the transformer and I could hear the loud, angry 60 Hz buzzing that sounded like a million hornet nests. As I passed, the transformer exploded and released a cloud of flaming liquid that rained down on the road and lawns underneath. It seemed like a good time to quit rubbernecking and beat it as fast as I could.

I knew at the time that the flaming liquid was transformer oil, but I never really knew what it was for or why it was in there. Oil is just one of many liquid dielectrics that are found in a lot of power distribution equipment, from those transformers on the pole to the big capacitors and switchgear in the local substation. Liquid dielectrics are interesting materials that are worth taking a look at.

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