#video #toread where #Mr-Electron suggests #DIY #manufacturing of a 20kWh “lifetime battery” which is apparently encased in concrete?
on 02026-01-14#video about #Mr-Electron #manufacturing #aluminum-air #batteries with a carbon brush from a motor as the cathode in a potassium hydroxide electrolyte, or some bent-up baling wire. He’s hacksawing the top off a lead-acid battery case from an old motorbike and gets an open-circuit voltage of about 1.6 volts and a short-circuit current that’s initially 20mA with an aluminum-foil anode; when he replaces the carbon-brush cathode with the bent-up baling wire this jumps to 40–80mA. #hoarding #electronics #energy #toread
on 02024-10-18#video about #manufacturing #aluminum-air #batteries with #3D-printing ABS. He says potassium hydroxide will eat PLA, which makes sense but which I hadn’t realized. #Mr-Electron here is using steel baling wire for his cathodes. For his anode he cuts up thick aluminum sheet metal with shears and then presses it flat in a vise. Each aluminum anode plate is crimped onto baling wire from the following cell in the battery using a hammer and anvil. He gets 10.2V open-circuit voltage from 8 series cells. I’m unclear how air is supposed to get to his cathodes. He does some load testing with small electric motors but doesn’t actually measure the current. The short-circuit current he measures is 160mA and rapidly dropping. After testing with LEDs for a while the open-circuit voltage has dropped to 3.8 volts. Later he cuts cathode forms out of CDs with an angle grinder and cutoff disc, wrapping them tightly with baling wire to maximize area. His higher-current anodes are aluminum-foil-wrapped popsicle sticks, dimensioned to fit inside the battery compartments, but for whatever reason he didn’t install the plates parallel, resulting in a dramatically unnecessarily high internal battery resistance, which he doesn’t bother to measure, but he gets 240mA out of it. His connections to the aluminum plates are made by torquing a pringled steel washer down onto their non-submerged ends with a bolt. The 6 cells in series ought to give about 9.6 volts open-circuit, but instead he gets only 4.8V (0.8V per cell), which he blames on residual sulfuric acid contamination, but commenter “gsestream” suggests might be due to a lack of oxygen. He uses a DFRobot USB boost converter to charge his cellphone. #bootstrapping #scouting #jugaad
on 02024-10-18