inverter

62 Articles

Mods Turn Junk UPS Into A Long-Endurance Beast

December 15, 2023 by 36 Comments

If you’ve got a so-called uninterruptible power supply (UPS) on your system, you’re probably painfully aware that the “uninterruptible” part has some pretty serious limits. Most consumer units are designed to provide power during a black out only long enough to gracefully shut down your system. But with a few hacks like these, you can stretch that time out and turn it into a long-endurance UPS.

As many good stories do, this one starts in the trash, where [MetaphysicalEngineer] spotted an APC home office-style UPS. It was clearly labeled “broken,” but that just turned out to be a dead battery. While he could have simply replaced it with a 12-volt sealed lead-acid battery, [Meta] knew that his computer setup would quickly deplete the standard battery. A little testing showed him that a car battery would extend the run time significantly, especially if he threw in some extra cooling for the onboard inverter.

His final design uses a marine deep-cycle battery in a plastic battery box with the UPS mounted on top. The vacated battery compartment made a great place to add a cooling fan, along with a clever circuit to turn it on only when the beeper on the UPS sounds, with a bonus volume control for the annoying sound. He also added accessories to the battery box top, including a voltmeter, a USB charger, and a switched 12-volt power outlet. And kudos for the liberal use of fuses in the build; things could get spicy otherwise. The video below shows the entire build along with all the testing. [MetaphysicalEngineer] managed to triple the estimated runtime for the load he’s trying to power, so it seems like a win to us.

If your needs run more toward keeping your networking gear running through a blackout, you might want to check out this inverter-less DC UPS.

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Vehicle-to-Grid Made Easy

May 25, 2023 by 37 Comments

As electric cars continue to see increased adoption, one associated technology that was touted long ago that still hasn’t seen widespread adoption is vehicle-to-grid or vehicle-to-home. Since most cars are parked most of the time, this would allow the cars to perform load-levelling for the grid or even act as emergency generators on an individual basis when needed. While this hasn’t panned out for a variety of reasons, it is still possible to use an EV battery for use off-grid or as part of a grid tie solar system, and now you can do it without needing to disassemble the battery packs at all.

Normally when attempting to use a scrapped EV battery for another use, the cells would be removed from the OEM pack and reorganized to a specific voltage. This build, however, eliminates the need to modify the packs at all. A LilyGO ESP32 is used to convert the CAN bus messages from the battery pack to the Modbus communications protocol used by the inverters, in this case a Fronius Gen24, so the inverter and battery can coordinate energy delivery from one to the other automatically. With the hard part out of the way, the only other requirements are to connect a high voltage DC cable from the battery pack to the inverter.

[Dala], the creator of this project, has taken other steps to ensure safety as well that we’d recommend anyone attempting to recreate this build pays close attention to, as these battery packs contain an extremely large amount of energy. The system itself supports battery packs from Nissan Leafs as well as the Tesla Model 3, which can usually be found for comparably low prices. Building battery energy storage systems to make up for the lack of commercially-available vehicle-to-home systems isn’t the only use for an old EV battery, though. For example, it’s possible to use Leaf batteries to triple the range of other EVs like [Muxsan] did with this Nissan van.

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Converting On-Grid Electronics To Off-Grid

May 11, 2023 by 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%

Home, sorry, truck automation system

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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Unlocking A Locked-Down Inverter

November 25, 2022 by 21 Comments

There was a time when a mains inverter was a heavy, expensive, and not particularly powerful item, but thanks to switch-mode technology we are now spoiled for choice. Most inverters still work with 12 V or 24 V supplies though, so when [Chris Jones] was looking for one to run from 36 V batteries, he found a limited supply. Sadly the Greenworks model he ended up with was affordable, but locked to a particular battery by means of a serial line between battery and inverter. Buy the special battery? No, he did what any hacker would do, and modified the inverter to do without it.

Tracing the serial link led to a mystery chip, probably a microcontroller but without available data. It in turn had a line to an 8051 derivative that seemed to be the brains of the operation. Acting on a hunch he pulled down the line with a resistor, and as if by magic, a working inverter appeared.

As you might expect, here at Hackaday we abhor such tricks by manufacturers, and thus any moves to circumvent them are to be applauded. It would be extremely interesting were anyone to have the Greenworks battery to subject to some reverse engineering of the profile.

Meanwhile if this is a little complex for you, there is a much simpler way to make a rough and ready inverter.

Ryobi Battery Hack Keeps CPAP Running Quietly

August 23, 2022 by 34 Comments

When it comes to cordless power tools, color is an important brand selection criterion. There’s Milwaukee red, for the rich people, the black and yellow of DeWalt, and Makita has a sort of teal thing going on. But when you see that painful shade of fluorescent green, you know you’ve got one of the wide range of bargain tools and accessories that only Ryobi can offer.

Like many of us, Redditor [Grunthos503] had a few junked Ryobi tools lying about, and managed to cobble together this battery-powered inverter for light-duty applications. The build started with a broken Ryobi charger, whose main feature was a fairly large case once relieved of its defunct guts, plus an existing socket for 18-volt battery packs. Added to that was a small Ryobi inverter, which normally plugs into the Ryobi battery pack and converts the 18 VDC to 120 VAC. Sadly, though, the inverter fan is loud, and the battery socket is sketchy. But with a little case modding and a liberal amount of hot glue, the inverter found a new home inside the charger case, with a new, quieter fan and even an XT60 connector for non-brand batteries.

It’s a simple hack, but one that [Grunthos503] may really need someday, as it’s intended to run a CPAP machine in case of a power outage — hence the need for a fan that’s quiet enough to sleep with. And it’s a pretty good hack — we honestly had to look twice to see what was done here. Maybe it was just the green plastic dazzling us. Although maybe we’re too hard on Ryobi — after all, they are pretty hackable.

Thanks to [Risu no Kairu] for the tip on this one.

Supersized Power Bank Built From An EV Battery

February 3, 2022 by 25 Comments

Perhaps one day in the future when our portable electronics are powered by inexhaustible dilithium crystals, we’ll look back fondly on the 2020s when we carried around power banks to revive our flagging tech. Oh how we laughed as we reached for those handy plastic bricks only to find them drained already of juice, we’ll say. [Handy Geng] won’t be joining us though, because he’s made the ultimate power bank, a 27,000 AH leviathan that uses an electric car battery for storage and supplies mains power through a brace of sockets on its end.

The vehicle battery is mounted on a wheeled trolley along with what appears to be either the in-car charging unit or a mains inverter. The whole thing is styled to look like a huge version of a pocket power bank, with a curved sheet metal shell and white hardboard end panels. The demonstration pushes the comedy further, as after charging a huge pile of phones he replenishes an electric scooter before settling sown by a chilly-looking river for a spot of fishing — along with his washing machine, TV, and electric hotpot for a spot of cooking. We appreciate the joke, and as we know him of old we’re looking forward to more.

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Quick And (Not Very) Dirty Negative Voltage Supply

November 16, 2021 by 11 Comments

There comes a time in every hardware hacker’s career during which they first realize they need a negative voltage rail in their project. There also comes a time, usually ~10ms after realizing this, when they reach for the Art of Electronics to try and figure out how the heck to actually introduce subzero voltages into their design. As it turns out, there are a ton of ways to get the job done, from expensive power supplies to fancy regulators you can design, but if you’re lazy (like I am) you might just want a simple, nearly drop-in solution.

[Filip Piorski] has got you covered there. In a recent video, he demonstrates how to turn a “China Special” $1 buck converter from Ebay into a boost-buck converter, capable of acting as a negative voltage supply. He realized that by swapping around the inputs and outputs of the regulator you can essentially invert the potential produced. There are a few caveats, of course, including high start-up current and limited max. voltages, but he manages to circumvent some of them with a little clever rewiring and a bit of bodge work.

Of course, if you have strict power supply requirements you probably want to shell out the cash for a professionally-built one, or design one yourself that meets your exact needs. For the majority of us, a quick and easy solution like this will get the job done and allow us to focus on other aspects of the design without having to spend too much time worrying about the power supply. Of course, if power electronics design is your thing, we’ve got you covered there, too.

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