A Li-Ion Booster Pack, Done Right

May 27, 2018 by Jenny List 12 Comments

We’re all used to battery booster packs containing a Li-ion or Li-poly cell and a little inverter circuit, they are a standard part of 21st century daily survival for those moments when smartphone battery lives don’t perform as advertised. But how many of us have considered what goes into them, and further how many of us have sought to produce the best one possible rather than a unit built at the lowest price?

It’s a course [Peter6960] has followed, producing a PCB that sits on the back of an 18650 cell holder. It follows the work of [GreatScott] in particular in its use of the TP4056 charger, MT3608 boost converter, and FS312F protection ICs. Many commercial modules omit any protection circuit, and the FS312F is of particular interest because it has a low 2.9V cut-off voltage that should lengthen the life of the cell. Files for the PCB can be found in a zip file hosted on Google Drive.

You might think that there was nothing new that could be learned about a Li-ion battery booster, but it’s always worth a look at a well-executed piece of work. We noticed he refers to Li-poly cells while using what appears to be a Li-ion 18650 cell. Most likely this is merely an oversight.

There is a lot to know about the characteristics and safety of the lithium-chemistry rechargeables, you may find [Sean Boyce]’s article on the subject to be an interesting read.

Hybrid Bench Power Supply Can Also Hit The Road

May 18, 2018 by Dan Maloney 4 Comments

Everyone needs a bench power supply, and rolling your own has almost become a rite of passage for hackers. For a long time, the platform of choice for such builds seemed to be the ATX power supply from a computer. While we certainly still see those builds, a lot of the action has switched to those cheap eBay programmable DC-DC converters, with their particolored digital displays.

This hybrid bench and portable power supply is a good example of what can be accomplished with these modules, and looks like it might turn out to be a handy tool. [Luke] centered his build around the DPS3003, a constant current and constant voltage buck converter that can take up to 40-VDC input and outputs up to 32 volts at 3 amps. In bench mode, the programmable module is fed from a mains-powered 24-volt switching supply. For portable work, an 18-volt battery from a Makita drill slips into a 3D-printed adapter on the top of the case. The printed part contains a commercial terminal [Luke] scored on eBay, but we’d bet the entire thing could be 3D printed. And no problem if you change power tool brands — just print another adapter.

Those little eBay power supply modules have proven to be an enabling technology, at least judging by the number of clever ways we’ve seen them used lately. From this combination bench PSU and soldering iron supply to a portable PSU perched atop a battery, these things are everywhere. Heck, you can even reflash the firmware and make them do your bidding.

[via Dangerous Prototypes]

Vastly Improving The Battery Life On Cheap Action Cams

April 28, 2018 by Brian Benchoff 21 Comments

At one time, GoPro was valued at over eleven Billion dollars. It’s now on the verge of being a penny stock, because if surfers can make action cams and video editing software, anyone can. Action cams are everywhere, and one of the cheapest is the SQ11. It’s a rip-off of the Polaroid Cube, has a non-standard USB socket, a tiny battery, and the video isn’t that great. It only costs eight dollars, though, so [pixelk] decided to vastly expand the abilities of this cheap camera for a Hackaday Prize entry.

The major shortcoming of the SQ11 action cam is the tiny battery. Reportedly, it’s a 200 mAh battery, but the stated 1-2 hours of runtime bears no resemblance to reality. The solution to this problem, as with most things in life, is to throw some lithium cells at the problem.

[pixelk] disassembled the SQ11 action cam and 3D printed a much longer enclosure meant to fit a single 18650 battery. There’s a protection circuit, so that’s fine, but there’s still a problem: the charging circuit in the camera is tailored for a 200 mAh battery — charging an 18650 cell would probably take a day. That’s no problem, because this enclosure leaves the battery removable, for easy recharging in an external device.

Does this make the SQ11 a good camera? Marginally, yes. If you need to record video for hours and hours, you won’t be able to do better than an eight dollar camera and four dollars in parts.

Assemble Your Own Modular Li-Ion Batteries

April 23, 2018 by Drew Risinger 50 Comments

Low-voltage DC power electronics are an exciting field right now. Easy access to 18650 battery cells and an abundance of used Li-Ion cells from laptops, phones, etc. has opened the door for hackers building their own battery packs from these cheap cells. A big issue has been the actual construction of a pack that can handle your individual power needs. If you’re just assembling a pack to drive a small LED, you can probably get by with spring contacts. When you need to power an e-bike or other high power application, you need a different solution. A spot welder that costs $1000 is probably the best tool, but out of most hackers’ budget. A better solution is needed.

Enter [Micah Toll] and his Vruzend battery connectors, whose Kickstarter campaign has exceded its goal several times over. These connectors snap onto the ends of standard 18650 cells, and slot together to form a custom-sized battery pack. Threaded rods extend from each plastic cap to enable connection to a bus bar with just a single nut. The way that you connect each 18650 cell determines the battery pack’s voltage and current capability. There are a couple of versions of the connector available through the campaign, and the latest version 2.0 should allow some tremendously powerful battery pack designs. The key upgrade is that it now features corrosion-resistant, high-power nickel-plated copper busbars allowing current up to 20A continuous. A side benefit of these caps instead of welded tabs is that you can easily swap out battery cells if one fails or degrades over time. Continue reading “Assemble Your Own Modular Li-Ion Batteries” →

Fail Of The Week: An Electric Bicycle, Powered By AA Batteries

April 17, 2018 by Brian Benchoff 47 Comments

Very slowly, some very cool parts are coming out on the market that will make for some awesome builds. Supercapacitors are becoming a thing, and every year, the price of these high power supercaps go a little lower, and the capacity gets a little higher. It’s really only a matter of time before someone hacks some supercaps into an application that’s never been seen before. The Navy is doing it with railguns, and [David] is building an electric bike, powered by AA batteries. While [David]’s bike technically works with the most liberal interpretation of ‘technically’, it’s the journey that counts here.

This project began as an investigation into using supercapacitors in an electric bicycle. Supercaps have an energy density very much above regular capacitors, but far behind lithium cells. Like lithium cells, they need a charge balancer, but if you manage to get everything right you can trickle charge them while still being able to dump all that power in seconds. It’s the perfect application for a rail gun, or for slightly more pedestrian applications, an electric bike with a hill assist button. The idea for this build would be to charge supercaps from a bank of regular ‘ol batteries, and zoom up a hill with about fifteen seconds of assistance.

The design of the pulsed power DC supply is fairly straightforward, with a mouthful of batteries feeding the supercap array through boost regulators, and finally going out to the motor through another set of regulators. Unfortunately, this project never quite worked out. Everything worked; it’s just this isn’t the application for the current generation of supercapacitors. There’s not enough energy density in [David]’s 100F supercaps, and the charging speed from a bunch of AA batteries is slow. For fifteen minutes of charging, [David] gets about fifteen seconds of boost on his bike. That’s great if you only ever have one hill to climb, but really useless in the real world.

That doesn’t mean this project was a complete failure. [David] now has a handy, extremely resilient array of supercaps that will charge off of anything and provide a steady 24V for a surprising amount of time. Right now, he’s using this scrapped project as a backup power supply for his 3D printer. That 100 Watt heated bed slurps down the electrons, but with this repurposed supercap bank, it can survive a 20 second power outage.

It’s a great project, and even if the technology behind supercaps isn’t quite ready to be used as a boost button on an electric bike, it’s still a great example of DIY ingenuity. You can check out [David]’s demo of the supercap bank in action below.

Continue reading “Fail Of The Week: An Electric Bicycle, Powered By AA Batteries” →

Recharging Drones On The Go With A Supercharger

April 10, 2018 by Brian Benchoff 45 Comments

If Techcrunch is to be believed, our skies will soon be filled with delivery robots, ferrying tacos and Chinese food and Amazon purchases from neighborhood-area dispatch stations to your front door. All of this is predicated on the ability of quadcopters to rapidly recharge their batteries, or at the very least swap out batteries automatically.

For their Hackaday Prize entry, [frasanz], [ferminduaso], and [david canas] are building the infrastructure that will make delivery drones possible. It’s a drone supercharger, or a robot that grabs a drone, swaps out the battery, and sends it off to deliver whatever is in its cargo compartment.

This build is a droneport of sorts, designed to have a drone land on it, have a few stepper motors and movable arms spring into action, and replace the battery with a quick-change mechanism. This can be significantly more difficult than it sounds — you need to grab the drone and replace the battery, something that’s easy for human eyes and hands, but much harder for a few sensors and aluminum extrusion.

To change batteries, the team is just letting the drone land somewhere on a platform that’s a few feet square. Arms then move it, pushing the drone to the center, and a second arm then moves in to swap the battery. The team is using an interesting locking cam solution to clamp the battery to the drone. It’s much easier for a machine to connect than the standard XT-60 connector found on race quads.

Is this the project the world needs? Quite possibly so. Drones are going to be awesome once battery life improves. Until then, we’ll have to live with limited flight times and drone superchargers.

Continue reading “Recharging Drones On The Go With A Supercharger” →

Giving A 6th Generation IPod A New Lease On Life

March 30, 2018 by James Hobson 13 Comments

It can be disheartening when a favoured device begins to break-down. Afflicted by an all-but-dead battery and a fritzing-out hard drive, Redditor [cswimc] sensed the imminent doom creeping up on their 6th generation iPod, and responded by reviving and upgrading the decrepit device instead!

It’s no easy task to crack open one of these things, so they found themselves taking their time and carefully wedging the pry tool between the front and back covers, working their way around the exterior. Once separated, gingerly disconnecting the few ribbon cables allowed the iPod to be opened fully. From there, they turned to swapping out the original hard drive for an iFlash dual SD card board — one of the cards turned out to be a dud, but 128GB is still a step up from 80GB — and a new 3000mAh battery. Combined with replacing the power-hungry HDD, the battery life has been overwhelmingly increased over the original’s 650mAh capacity!

Continue reading “Giving A 6th Generation IPod A New Lease On Life” →