Hackaday Prize Semifinalist: A Smart Battery Analyzer

[K.C. Lee]’s entry for the Hackaday Prize won’t cure cancer, wipe a disease from the planet, stop an alien invasion, or save the world. His battery charger and analyzer is, however, a useful little device for determining the charge and discharge characteristics of batteries, and can also be used as dual channel electronic load, current source, or power supply.

Inside [K.C.]’s device are all the tools required for charging and discharging lithium-ion, lead acid, and NiMH batteries. He’s doing this with a few slightly unusual circuits, including a SEPIC DC to DC converter, and an ‘analog’ PWM controller. these two techniques together mean [K.C.] can get away with smaller caps and inductors in his design, which also means less ripple on the output. As far as battery chargers and dischargers go, this one is very well designed.

Control of battery discharging and charging happens through a SILabs 8051-based microcontroller with USB. The UI is a simple Nokia LCD and an app running in Windows. If you want to save the world, this isn’t the project for you. If you need to test a few rechargeable batteries, this is a great device to have on the workbench.

The 2015 Hackaday Prize is sponsored by:

Where Are They Now: Terrible Kickstarters

Kickstarter started out as a platform for group buys, low-volume manufacturing, and a place to fund projects that would otherwise go unfinished. It would be naive of anyone to think this would last forever, and since these humble beginnings, we’re well into Peak Kickstarter. Now, Kickstarter, Indiegogo, and every other crowdfunding platform is just another mouthpiece for product launches, and just another strategy for anyone who needs or wants money, but has never heard of a business loan.

Of course there will be some shady businesses trying to cash in on the Kickstarter craze, and over the last few years we’ve done our best to point out the bad ones. Finding every terrible Kickstarter is several full-time jobs, but we’ve done our best to weed out these shining examples of the worst. Following up on these failed projects is something we have been neglecting, but no longer.

Below are some of the most outrageous Kickstarters and crowdfunding campaigns we’ve run across, and the current status of these failed entrepreneurial endeavors.

Continue reading “Where Are They Now: Terrible Kickstarters”

Building a Battery from Molten Salt

During World War II a scientist named Georg Otto Erb developed the molten salt battery for use in military applications. The war ended before Erb’s batteries found any real use, but British Intelligence wrote a report about the technology and the United States adopted the technology for artillery fuses.

Molten salt batteries have two main advantages. First, you can store them for a long time (50 years or more) with no problems. Once the salt melts (usually from a pyrotechnic charge), the battery can produce a lot of energy for a relatively short period of time thanks to the high ionic conductivity of the electrolyte (about three times that of sulfuric acid).

[OrbitalDesigns] couldn’t find a DIY version of a molten salt battery so he decided to make one himself. Although he didn’t get the amount of power you’d find in a commercial design, it did provide 1.6V and enough power to light an LED.

The electrolyte was a mixture of potassium chloride and lithium chloride and melts at about 350 to 400 degrees Celsius. He used nickel and magnesium for electrodes. Potassium chloride is used as a salt substitute, so it isn’t dangerous to handle (at least, no more dangerous than anything else heated to 400 degrees Celsius). The lithium compound, however, is slightly toxic (even though it was briefly sold as a salt substitute, also). If you try to replicate the battery, be sure you read the MSDS for all the materials.

Continue reading “Building a Battery from Molten Salt”

One Way to Recharge Alkaline Batteries

It says it right on the side of every alkaline battery – do not attempt to recharge. By which of course the manufacturer means don’t try to force electrons back into the cell. But [Cody] figured he could work around that safety warning chemically, by replacing the guts of an alkaline dry cell.

The batteries in question were certainly old, gnarly looking, and pretty dead – [Cody] barely got a reading on his multimeter. As you can see after the break, he cleaned off the exterior corrosion and did a quick teardown of the dry cells, removing the remains of the zinc anode, now in the form of zinc oxide paste looking very much like what you’d slather on your nose before a day at the beach. He filled the resulting cavity with a putty of zinc dust, freshened up the electrolyte charge with a squirt of 20% potassium hydroxide, sealed up the cell with a little silicone caulking, and put the recycled cell to the test. Result: 1.27 volts. Not too shabby.

Continue reading “One Way to Recharge Alkaline Batteries”

Field Expedient Stick Welder from Cordless Tool Battery Packs

The self-proclaimed and actual “smartest idiot on YouTube” is back with another entry from the “don’t try this at home” file. [AvE] recently did a teardown of a new DeWalt cordless drill-driver, and after managing to get everything back together, he was challenged by a viewer to repurpose the 20V battery packs into an impromptu stick welder.

AvE_short[AvE] delivered – sort of. His first attempt was with the two battery packs in parallel for higher current, but he had trouble striking an arc with the 1/8″ rod he was using. A freeze-frame revealed an incredible 160A of short-circuit current and a welding rod approaching the point of turning into plasma. Switching to series mode, [AvE] was able to strike a reasonable arc and eventually lay down a single splattery tack weld, which honestly looks better than some of our MIG welds. Eventually his rig released the blue smoke, and the postmortem teardown of the defunct packs was both entertaining and educational.

While we can’t recommend destroying $100 worth of lithium-ion battery packs for a single tack weld, it’s interesting to see how much power you’re holding in the palm of your hand with one of these cordless drills. We saw a similar technique a few years back in a slightly more sophisticated build; sadly, the YouTube video in that post isn’t active anymore. But you can always stay tuned after the break for the original [AvE] DeWalt teardown, wherein blue smoke of a different nature is released.

Continue reading “Field Expedient Stick Welder from Cordless Tool Battery Packs”

Frankensteined Cordless Drill Lives Again

With tools, especially cordless tools, you’re going to pay now or pay later. On one hand, you can spend a bunch of money up front and get a quality tool that will last a long time. The other option is purchasing a cheap cordless tool that won’t last long, having to replace it later and thus spending more money. With cheap cordless tools it is common for the battery to fail before the physical tool making that tool completely unusable. Sure, another battery could be purchased but sometimes they cost just as much as the tool and battery combo originally did. So what’s a cordless tool user to do?

[EngergySaver] had a set of DeWalt cordless tools with a bunch of working batteries. He also had a cheap drill where the battery had died. His bundle of tools included two flashlights, one of which the case physically broke in half, probably from a clumsy drop. Instead of tossing the broken flashlight pieces in the garbage, [EngergySaver] kept them around for a while. Then one day he had the idea of combining the base of the broken DeWalt flashlight with the top of the old battery-less drill. He had the parts so why not?

The battery pack was 18 volt and the cheap drill expected 16.8 volts. [EngergySaver] figured the voltages were close enough and decided not to worry about the difference during his hack. He started by disassembling both the drill and flashlight down to the bare plastic housings. He marked an appropriate place to splice the handles and made some cuts. After the wiring was spliced together and the tool casings reassembled, a piece of sheet metal was cut and bent around the handle at the joint between flashlight and drill. Hose clamps hold the sheet metal tight around the handles, keeping the new hybrid tool together. And although we’re not crazy about the sheet metal and hose clamp method, it seems to be working just fine. With a little work and ingenuity [EngergySaver] resurrected an old tool for our favorite price; $0.

The Best NiMh Charger?

[Paul Allen] has been working on the latest iteration of his NiMh battery charger and it looks amazing!

We’ve covered [Paul Allen]s awesome hacks and tutorials before, but never this project. What makes his charger so special is it’s ability to monitor and log every aspect of the charging process. Not only does it have a SD card for data logging, but it also interfaces with a Windows application for real-time monitoring as well as analysis and visualization of the charging process (Linux users don’t fret it has a serial interface too).

[Paul] doesn’t say if he plans to open hardware or kickstart the charger, but some of his older posts give us a quick peak at the gerbers. Let’s hope this awesome project makes its way into the wild soon, and hopefully we’ll be able to try it for ourselves and see if it lives up to its name.