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”
You can find galvanized steel pipes at Home Depots and construction sites all around the world. These relatively thin-walled steel pipes would make for great structural members if it weren’t for the fact they were covered in a protective layer of zinc. This layer of galvanization lends itself to crappy welds and some terrible fumes, but badass, TV personality, and hacker extraordinaire [Hackett] shows us how to strip the galvanization off these pipes with chemicals available at any hardware store.
Since the galvanization on these pipes covers the inside and the outside, grinding the small layer of zinc off these pipes is difficult at best. To be sure he gets all the zinc off this pipe, [Hackett] decided to chemically strip the pipes with a cup full of muriatic acid.
The process is simple enough – fill a cup with acid, dunk the ends of the pipes, and clean everything up with baking soda. A great way to turn scrap pipe into a usable material, make a cool paper mache volcano, and avoid ‘ol galvie flu
Continue reading “On not getting metal fume fever with galvanized conduit”
Batteries come packaged in bright blister packs emblazoned with vague guarantees such as “45% more pictures” and “five times longer lasting.” During his internship at BitBox this summer, [Thomas] decided to put those statements to the test. He tested thirty brands of batteries on a homebrew rig to find the batteries with the most power and the most bang for your buck.
The hardware [Thomas] used an STM32 microcontroller to perform two different tests: a high drain and a low drain condition. For the high drain, 1000 mA were sucked out of the batteries until the voltage reached 0.8 V. For the low drain, 200 mA were used. Data including milliwatt-hours, milliamp-hours, joules, voltage, current, power, and effective load resistance were all logged for both conditions for all 30 batteries.
Generalizing the results for both low and high drain conditions, lithium batteries were better than alkaline, which were both better than zinc AA cells. Perhaps unsurprisingly, batteries marketed as ‘long life’ and ‘extended power’ were the worst batteries for the money, but a brand-name battery – the Kodak Xtralife cells – were actually the best value for the money.
Apparently being overrun by ripe Passion Fruit is a problem if you live in Hawaii. [Ryan K’s] solution to the situation was to use his extra fruit to power a laser. In an experiment that would make [Walter White] proud, [Ryan] gathered everyday supplies to form a battery based on the fruit.
He used some galvanized bolts as the source of zinc. It forms one pole of each cell, with a thin copper tube as the other pole. Each cell is rather weak, but when combined with others it makes a respectable battery. We’ve seen acidic fruit used to power LEDs, but [Ryan] wanted to do a little more. He built a circuit that would store electricity until he had enough potential to power an LED diode. After the break you can see a four second clip of the fruit wielding its new laser defense system.
Continue reading “Passion Fruit acquire laser defenses”
[Jeri Ellsworth] continues her experiments with electroluminescence, this time she’s making EL ink. The ink she’s looking for is Zinc Sulfate in a solution. The process she chose is to re-dope some glow powder so that it can be excited by the field around an AC current. In her video (embedded after the break) she talks about the chemical properties she’s after by detailing a cubic lattice of zinc and sulfur atoms with an added copper atom (adding that atom is a process called doping).
The quick and dirty synopsis of the experiment starts by washing the glow powder with dish soap to acquire zinc sulfide crystals. Then she combined copper sulfate and zinc shavings from the inside of a modern penny to yield copper metal and zinc sulfate suspended in solution. That was mixed with the zinc sulfide from the glow powder washing and doped with a little more copper sulfate. The excess liquid is poured off, the test tube is capped with glass frit, and the whole thing hits the kiln to start the reaction. The result glows when excited by alternating current, but could have been improved by adding chlorine atoms into the mix.
We’re excited every time we see one of [Jeri’s] new chemistry hacks. We’d love to see more so if you’ve come across interesting chemistry experiments during your Internet travels, please let us know about them. Just make sure you have some idea of what you’re doing when working with chemicals… safety first.
Continue reading “More EL chemistry: Luminescent ink”