The pack is designed to be charged via solar panels, at 18 V and up to 5 A of current. It’s intended to work with a Maximum Power Point Tracking module to ensure the maximum energy is gained from the sunshine available. For storage, the pack relies on 75 individual 18650 lithium cells, arranged with 3 cells in series, each with 25 in parallel (3s25p). They’re spot welded together for strength and good conductivity. Nominally, the output voltage is on the order of 10-12 V. The included battery management system (BMS) will allow an output current up to 100 A, and the pack can be used with an AC inverter to power regular home appliances.
Overall, it’s a tidy pack that’s more than capable of keeping a few devices charged up for days at a time. If you’re building something similar yourself, though, just be sure to package it well and keep it protected. So many lithium batteries can quickly turn fiery if something goes wrong, so store and use it appropriately! Fear not, however – we’ve got a guide on how to do just that.
Hackaday Prize 2021 entrant [Philip Ian Haasnoot] has been building a well-polished power bank. But this is no ordinary little power bank the like you would throw in your rucksack for a day out. No, this 2.5 kW luggable power bank is neatly encased in a tough, waterproof Pelican 1550 case, and is suitably decked out with all the power sockets you could possibly need for a long weekend of wilderness camping and photography.
This box sports USB-C and USB 3.0 connectors for gadget charging, as well as 12 VDC cigarette lighter and XT-60 ports for high-drag devices. Also it provides a pair of 120 VAC sockets via an integrated inverter, which at 1.5 kW could run a small heater if you were really desperate, but more likely useful to keep your laptop going for a while. Now if only you could get Wi-Fi out in the desert!
[Philip] doesn’t actually talk much about the solar panels themselves, but we know the box contains a 600 W MPPT boost converter to take solar power in, and feed the LiPo battery pack in the correct manner.
The battery pack is custom-made from salvaged and tested 18650 cells, as you would expect, which we reckon took an absolute age to make by hand. The whole project is nicely finished, and looks like something we’d be happy to throw in the back of the car before heading out into our local wilderness.
As [Philip] says in the project description, it’s a tough job to carry enough power and keep all his drones, cameras and lighting equipment charged, not mention helping prevent the campsite occupants from freezing overnight during the chilly Arizona nights.
Many power bank designs have graced these fair pages over the years, like this rather polished build, and long may they continue to do so.
Even the most secular among us can understand why somebody would want to have a digital version of the Bible. If you’re the sort of person who takes solace in reading from the “Good Book”, you’d probably like the ability to do so wherever and whenever possible. But as it so happens, a large number of people who would be interested in a more conveniently transportable version of the Bible may not have the technological wherewithal to operate a Kindle and download a copy.
Which is precisely the idea behind the Wonder Bible, a pocket-sized electronic device that allows the user to listen to the Bible read aloud at the press of a button. Its conservative design, high-contrast LED display, and large buttons makes it easy to operate even by users with limited eyesight or dexterity.
The commercial for the Wonder Bible shows people all of all ages using the device, but it’s not very difficult to read between the lines and see who the gadget is really aimed for. We catch a glimpse of a young businessman tucking a Wonder Bible into the center console of his expensive sports car, but in reality, the scenes of a retiree sitting pensively in her living room are far closer to the mark.
In truth, the functionality of the Wonder Bible could easily be replicated with a smartphone application. It would arguably even be an improvement by most standards. But not everyone is willing or able to go that route, which creates a market for an affordable stand-alone device. Is that market large enough to put a lot of expense and engineering time into the product? Let’s crack open one of these holy rolling personal companions and find out.
The build starts with 18650 lithium-ion cells sourced from a recycler, packed inside obsolete modem battery packs. After harvesting 390 cells, the best 364 are chosen and assembled into plastic holders to create a 14S26P configuration. A spot welder is employed to weld the pack together, with XT60 connectors used as the main bus connectors, albeit in a very non-standard configuration. Balance leads are hooked up to a 14S battery management system, to keep things in check. The huge pack is then installed inside a stout Craftsman toolbox, along with a MPPT solar charger module, and a 1500W inverter for output.
The build video is a great resource for anyone interested in building custom 18650 packs or battery solar power systems. [LithiumSolar] does a great job of clearly explaining each step and the reasons for part selections along the way. Of course, in a neat dovetail to this project, we’ve even seen solar-powered spot welders before – which would be useful if you need to replicate this build out in the field somewhere. Video after the break.
On the outside, a Geiger counter seems like a complicated thing. And you might think a device that detects a dangerous, mostly invisible threat like radiation should be complicated. But they’re actually pretty simple. The Geiger-Muller tube does most of the work, which boils down to detecting brief moments of conductivity caused by chain reactions of charged particles in radioactive materials.
[Prabhat_] wanted to build a unique-looking Geiger counter, and we’d say that this slick, Star Trek-esque result succeeds. A well-organized display shows the effective dose rate, counts per minute, and cumulative dose, which can be displayed in either microsieverts or millirems. We dig the 3D printed case design, because we like to see form follow function.
The counter is powered by an 18650 cell that’s DC-to-DC boosted to 400+ volts. A NodeMCU processes the signal coming in from the G-M tube and expresses it in both clicks and LED blinks, both of which can be toggled on or off from the home screen. The alert threshold can be customized in the settings, which means the point at which green changes to red.
Click-click-click past the break for [prabhat_]’s great walk-through video, where he tests it with uranium ore and a thoriated gas lantern mantle.
Back in the flip phone days, you could get through the whole weekend before you had to even think about plugging the thing in. But as the processing power of our mobile devices increased, so to did their energy consumption. Today you’re lucky if your phone doesn’t die before you make it home at the end of the day. To avoid the horrors of having to live without their mobile devices, many people have resorted to lugging around small “power banks” to keep their phones topped off.
That said, the “Ultimate 18650 Power Bank” created by [Kennedy Liu] is on a whole new level. Only true Road Warriors need apply for this particular piece of kit. Inside the 3D printed enclosure is…well, pretty much everything. It’s got an internal inverter to power your AC devices, a Qi wireless charging coil, an adjustable DC output, displays for all relevant voltages, and naturally plenty of USB ports to charge your gadgets. Oh, and some RGB LEDs tossed in for good measure.
[Kennedy] packed a lot of hardware into this relatively small package, and in the video after the break, shows off exactly how everything is arranged inside of this power bank. A big part of getting the whole thing together is the 3D printed frame, which includes carefully designed insets for all of the key components. So if you want to build your own version, you’ll need to get the exact same hardware he used to make sure the puzzle fits together. Luckily, he’s provided links for all the relevant components for exactly that purpose.
Now, you might be wondering about the wisdom of packing all this electronic gear into a thermoplastic enclosure. But [Kennedy] has thought about that; in addition to tacking a heatsink onto pretty much everything, he’s added fans for active cooling and a fairly robust thermal overload protection scheme. By mounting thermally controlled switches to the heatsinks of the high-output components, the system can cut power to anything getting too hot before it has a chance to melt the plastic (or worse).
For one reason or another, a lot of us have a bunch of 18650 cells sitting around. Whether they’re for flashlights, our fancy new vape pen, remote controlled toys, or something more obscure, there is a need to charge a bunch of lithium ion cells all at once. This project, by [Daren Schwenke], is the way to do it. It’ll charge ten 18650 cells quickly using a stock ATX power supply and less than twenty bucks in Amazon Prime parts.
The idea began when [Daren] realized his desktop lithium ion charger took between 4-6 hours to fully charge two 18650 cells. With a Mountainboard project, or a big ‘ol electric skateboard waiting in the wings, [Daren] realized there had to be a better solution to charging a bunch of 18650 cells. There is, and it’s those twenty bucks at Amazon and a few 3D printed parts.
The relevant parts are just a ten-pack of 18650 cell holders (with PC pins) and a ten-pack of 5V, 1A charging modules (non-referral Amazon link, support truly independent journalism) meant to be the brains of a small USB power bank. These parts were wired up to the 5V rail of a discarded ATX power supply (free, because you can scavenge these anywhere, and everything was wrapped up with a neat little 3D printed mount.
Is this the safest way to charge lithium ion cells? No, because you can build a similar project with bailing wire. There is no reverse polarity protection, and if there’s one thing you never want to do, it’s reverse the polarity. This is, however, a very effective and very cheap solution to charging a bunch of batteries. It does what it says it’ll do, nothing more.