Swapping Batteries Has Never Looked This Cool

November 29, 2024 by Donald Papp 39 Comments

We don’t know much more than what we see with [Kounotori_DIY]’s battery loader design (video embedded below) but it just looks so cool we had to share. Watch it in action, it’ll explain itself.

Before 3D printers made it onto hobbyist workbenches, prototyping something like this would have been much more work.

[Kounotori_DIY] uses a small plastic linear guide as an interface for an 18650 battery holder and as you can see, it’s pretty slick. A little cylindrical container slides out of the assembly, allowing a spent cell to drop out. Loading a freshly charged cell consists of just popping a new one into the cylinder, then snapping it closed. The electrical connection is made by two springy metal tabs on either end that fit into guides in the cylindrical holder.

It’s just a prototype right now, and [Kounotori_DIY] admits that the assembly is still a bit big and there’s no solid retention — a good bump will pop the battery out — but we think this is onto something. We can’t help but imagine how swapping batteries in such style with a nice solid click would go very nicely on a cyberdeck build.

It’s not every day that someone tries to re-imagine a battery holder, let alone with such style. Any ideas how it could be improved? Have your own ideas about reimagining how batteries are handled? Let us know in the comments!

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Lithium-Ion Battery Hotswapping, Polarity, Holders

September 11, 2024 by Arya Voronova 28 Comments

Everyone loves, and should respect, lithium-ion batteries. They pack a ton of power and can make our projects work better. I’ve gathered a number of tips and tricks about using them over the years, based on my own hacking and also lessons I’ve learned from others.

This installment includes a grab-bag of LiIon tricks that will help you supercharge your battery use, avoid some mistakes, and make your circuits even safer. Plus, I have a wonderful project that I just have to share.

Hot-swapping Cells

When your device runs out of juice, you might not always want to chain yourself to a wall charger. Wouldn’t it be cool if you could just hot-swap cells? Indeed it is, I’ve been doing it for years, it’s dead simple to support, but you can also do it wrong. Let me show you how to do it right!

Recently, a new handheld has hit the hacker markets – the Hackberry Pi. With a Blackberry keyboard and a colour screen, it’s a pretty standard entry into the trend of handheld Pi Zero-backed computers with Blackberry keyboards. It’s not open-source and the author does not plan to open-source its hardware, so I want to make it absolutely clear I don’t consider it hacker-friendly or worth promoting. It did publish schematics, though, and these helped me find a dangerous mistake that the first revision made when trying to implement LiIon battery hot-swap. Continue reading “Lithium-Ion Battery Hotswapping, Polarity, Holders” →

Connecting (And Using) High-Capacity Batteries In Parallel

May 27, 2024 by Bryan Cockfield 13 Comments

For those willing to put some elbow grease into it, there is an almost unlimited supply of 18650 lithium ion batteries around for cheap (or free) just waiting to be put into a battery pack of some sort. Old laptop and power tool batteries are prime sources, as these often fail because of one bad cell while the others are still perfectly usable. [limpkin] built a few of these battery packs and now that he’s built a few, he’s back with a new project that allows him to use four custom packs simultaneously.

The problem with using different battery packs in parallel is that unless the batteries are charged to similar voltages, they could generate a very high and potentially dangerous amount of current when connected in parallel. This circuit board, powered by a small ATtiny microcontroller, has four XT60 connectors for batteries and a fifth for output. It then watches for current draw from each of the batteries and, using a set of solid-state relays, makes sure that no dangerous over-current conditions occur if the batteries are connected with mismatched voltages. The code for the microcontroller is available on this GitHub page as well.

An array of batteries with a balancing system like this has a number of uses, from ebikes to off-grid power solutions, and of course if you build your own packs you’ll also want to build a cell balancer of some sort as well. Batteries go outside the realm of theory and into that of chemistry, so we’ll also provide a general warning about working in potentially dangerous situations without specialized knowledge, but you can see how [limpkin] built his original packs here if you want to take a look at one person’s strategy for repurposing old cells.

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Lithium-Ion Batteries Power Your Devboards Easily

March 14, 2024 by Arya Voronova 25 Comments

Last summer, I was hanging out with a friend from Netherlands for a week, and in the middle of that week, we decided to go on a 20 km bike trip to a nearby beach. Problem? We wanted to chat throughout the trip, but the wind noise was loud, and screaming at each other while cycling wouldn’t have been fun. I had some walkie-talkie software in mind, but only a single battery-powered Pi in my possession. So, I went into my workshop room, and half an hour later, walked out with a Pi Zero wrapped in a few cables.

I wish I could tell you that it worked out wonders. The Zero didn’t have enough CPU power, I only had single-core ones spare, and the software I had in mind would start to badly stutter every time we tried to run it in bidirectional mode. But the battery power solution was fantastic. If you need your hack to go mobile, read on.

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Open Source DC UPS Keeps The Low-Voltage Gear Going

December 22, 2023 by Dan Maloney 26 Comments

We all like to keep our network gear running during a power outage — trouble is, your standard consumer-grade uninterruptible power supply (UPS) tends to be overkill for routers and such. Their outlet strips built quickly get crowded with wall-warts, and why bother converting from DC to AC only to convert back again?

This common conundrum is the inspiration for [Walker]’s DC UPS design, which has some interesting features. First off, the design is open source, which of course invites tinkering and repurposing. The UPS is built for a 12 volt supply and load, but that obviously can be changed to suit your needs. The battery bank is a 4S3P design using 18650 cells, and that could be customized as well. There’s an ideal diode controller that prevents DC from back-feeding into the supply when the lights go out, and a really interesting synchronous buck-boost converter in place of the power management chip you’d normally see in a UPS. The converter chip takes a PWM signal from an RP2040; there’s also an ESP32 onboard for web server and UI duties as well as an STM32 to run the BMS. The video below discusses the design and shows a little of the build.

We’ve seen a spate of DC UPS designs lately, some more elaborate than others. This one has quite a few interesting chips that most of us don’t normally deal with, and it’s nice to see how they’re used in a practical design.

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2023 Halloween Hackfest: Converted Proton Pack Lights Up The Night

October 31, 2023 by Kristina Panos 6 Comments

It’s really quite unfortunate that Hackaday/Supplyframe employees and their families are not allowed to place in the 2023 Halloween Hackfest, because our own [Tom Nardi] has thrown down a costume gauntlet with his kids’ proton pack conversion.

Starting with an inert off-the-shelf toy from 2021, [Tom] set out to make the thing more awesome in every way possible. For one thing, it’s blue, and outside of the short-lived animated series The Real Ghostbusters, who ever heard of a blue proton pack? So one major change was to paint it matte black and age it with the old silver rub ‘n buff technique. And of course, add all the necessary stickers.

[Tom] added plenty of blinkenlights, all running off of an Arduino Nano clone and a pair of 18650s. He got lucky with the whole power cell thing, because an 8 x 5050 RGB LED stick fits there perfectly and looks great behind a PETG diffusing lens. He also drilled out and lit up the cyclotron, because what’s a proton pack without that? There’s even a 7-segment LED voltmeter so Dad can check the power level throughout the night.

Finally, he had to do a bit of engineering to make the thing actually wearable by his daughter. A frame made of square aluminium tubing adds strength, and a new pair of padded straps make it comfortable. Be sure to check it out in action after the break.

What’s a Ghostbusters costume without a PKE meter? Continue reading “2023 Halloween Hackfest: Converted Proton Pack Lights Up The Night” →

Dial Up A Tune On The Jukephone

October 10, 2023 by Kristina Panos 9 Comments

What do you do when you find a nice corded phone with giant buttons out in the wild? You could pay $80/month for a landline, use a VOIP or Bluetooth solution instead, or do something a million times cooler and turn it into a jukebox.

Now when the receiver is lifted, [Turi] hears music instead of a dial tone or a voice on the other end. But playback isn’t limited to the handset — there’s a headphone jack around back.

To listen to a track, he can either dial one in directly, or call up a random track using one of the smaller buttons below. A handy directory organizes the tunes by the hundreds, putting children’s tracks between 1-99 and the intriguing category “hits” between 900-999.

The phone’s new guts are commanded by a Raspberry Pi Pico, which is a great choice for handling the key matrix plus the rest of the buttons. As you may have guessed, there’s an DF Player Mini mp3 player that reads the tracks from an SD card. Everything is powered by a rechargeable 18650 battery.

Jukephone is open source, and you’ll find more pictures on [Turi]’s blog post. Be sure to check out the very brief build and demo video after the break.

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