We know you’ve got questions, and if you’re brave enough to ask the world for answers, then here’s the outlet to do so. This week’s Ask Engadget inquiry is from Bernard, who wants an answer to the age-old question of ensuring you get the most out of your batteries. If you’re looking to ask one of your own, drop us a line at ask [at] engadget [dawt] com.
“It’s said that you should always leave brand-new electronics plugged in for ‘a few hours’ after being fully charged, but how do you decide that period of time? Is there a calculation depending on the capacity of the battery, or what? Help me, please!”
Nowadays, do you even need to? While memory effect was an issue on NiCad batteries, Lithium Ion units don’t suffer from the same issue. It could also be tied to the belief that most chargers only re-juice batteries up to 95 percent, but we can’t find any authoritative proof on the matter. Let’s turn it over to the electrical engineers and battery experts who read Engadget on a regular basis so we can sort this out, once and for all!
While we’ve seen more than a few flexible batteries in our day, they’re not usually that great at withstanding tugs and pulls. A team-up between Northwestern University and the University of Illinois could give lithium-ion batteries that extreme elasticity with few of the drawbacks you’d expect. To make a stretchable battery that still maintains a typical density, researchers built electrode interconnects from serpentine metal wires that have even more wavy wires inside; the wires don’t require much space in normal use, but will unfurl in an ordered sequence as they’re pulled to their limits. The result is a prototype battery that can expand to three times its normal size, but can still last for eight to nine hours. It could also charge wirelessly, and thus would be wearable under the skin as well as over — imagine fully powered implants where an external battery is impractical or unsightly. There’s no word yet on whether there will be refined versions coming to real-world products, but we hope any developments arrive quickly enough to give stretchable electronics a viable power source.
Liquid solar cells are pretty neat, to be sure, but current-generating paint can be a hard color to match. Good thing, then, that researchers at Rice university have developed the perfect complement: a spray-on battery. By carefully layering five coats of specially formulated paint, the team has found a way to apply a thin coat of lithium ion storage to multiple surfaces, including glass, ceramics, steel and flexible polymers. Early experiments are promising — after applying the process to nine ordinary bathroom tiles, the painted batteries were able to power a small array of LEDs (spelling “Rice”) for six hours, consistently pumping out 2.4 volts of electricity. After 60 charge / discharge cycles, researches say the batteries retained most of their capacity. Neelam Singh, Rice graduate student and lead author of the team’s report, says the technology will only improve when coupled with modern methods. “Spray painting is already an industrial process, so it will be very easy to incorporate this into industry,” she said. “We really do consider this a paradigm changer.” Scope out the processes (and its fruits) for yourself after the break.
Have a BMW 3-Series that requires major engine work? Want to convert it to electric and improve performance, ActiveE style? The folks at Electric Motor Werks have you covered. Instead of making purpose-built electric cars, the company — which showed a converted 3-Series sedan and coupé at Maker Faire Bay Area 2012 — provides affordable and environmentally responsible electric conversion kits for the BMW E46. These are available directly to consumers but Electric Motor Werks is also building a network of installers (via tuner / speed shops) and setting up its own facilities.
We chatted with founder Val Miftakhov who gave us a tour of the prototype kit in the vehicles on display, so head past the break for more information and for our hands-on video.