Big Chemistry: Fuel Ethanol

If legend is to be believed, three disparate social forces in early 20th-century America – the temperance movement, the rise of car culture, and the Scots-Irish culture of the South – collided with unexpected results. The temperance movement managed to get Prohibition written into the Constitution, which rankled the rebellious spirit of the descendants of the Scots-Irish who settled the South. In response, some of them took to the backwoods with stills and sacks of corn, creating moonshine by the barrel for personal use and profit. And to avoid the consequences of this, they used their mechanical ingenuity to modify their Fords, Chevrolets, and Dodges to provide the speed needed to outrun the law.

Though that story may be somewhat apocryphal, at least one of those threads is still woven into the American story. The moonshiner’s hotrod morphed into NASCAR, one of the nation’s most-watched spectator sports, and informed much of the car culture of the 20th century in general. Unfortunately, that led in part to our current fossil fuel predicament and its attendant environmental consequences, which are now being addressed by replacing at least some of the gasoline we burn with the same “white lightning” those old moonshiners made. The cost-benefit analysis of ethanol as a fuel is open to debate, as is the wisdom of using food for motor fuel, but one thing’s for sure: turning corn into ethanol in industrially useful quantities isn’t easy, and it requires some Big Chemistry to get it done.
Continue reading “Big Chemistry: Fuel Ethanol”

A Look Inside A Lemon Of A Race Car

Automotive racing is a grueling endeavor, a test of one’s mental and physical prowess to push an engineered masterpiece to its limit. This is all the more true of 24 hour endurance races where teams tag team to get the most laps of a circuit in over a 24 hour period. The format pushes cars and drivers to the very limit. Doing so on a $500 budget as presented by the 24 hours of Lemons makes this all the more impressive!

Of course, racing on a $500 budget is difficult to say the least. All the expected Fédération Internationale de l’Automobile (FIA) safety requirements are still in place, including roll cage, seats and fire extinguisher. However, brakes, wheels, tires and safety equipment are not factored into the cost of the car, which is good because an FIA racing seat can run well in excess of the budget. Despite the name, most races are twelve to sixteen hours across two days, but 24 hour endurance races are run. The very limiting budget and amateur nature of the event has created a large amount of room for teams to get creative with car restorations and race car builds.

Continue reading “A Look Inside A Lemon Of A Race Car”

Fault Analysis Of A 120W Anker GaNPrime Charger

Taking a break from his usual prodding at suspicious AliExpress USB chargers, [DiodeGoneWild] recently had a gander at what used to be a good USB charger.

The Anker 737 USB charger prior to its autopsy. (Credit: DiodeGoneWild, YouTube)
The Anker 737 USB charger prior to its autopsy.

Before it went completely dead, the Anker 737 GaNPrime USB charger which a viewer sent him was capable of up to 120 Watts combined across its two USB-C and one USB-A outputs. Naturally the charger’s enclosure couldn’t be opened non-destructively, and it turned out to have (soft) potting compound filling up the voids, making it a treat to diagnose. Suffice it to say that these devices are not designed to be repaired.

With it being an autopsy, the unit got broken down into the individual PCBs, with a short detected that eventually got traced down to an IC marked ‘SW3536’, which is one of the ICs that communicates with the connected USB device to negotiate the voltage. With the one IC having shorted, it appears that it rendered the entire charger into an expensive paperweight.

Since the charger was already in pieces, the rest of the circuit and its ICs were also analyzed. Here the gallium nitride (GaN) part was found in the Navitas GaNFast NV6136A FET with integrated gate driver, along with an Infineon CoolGaN IGI60F1414A1L integrated power stage. Unfortunately all of the cool technology was rendered useless by one component developing a short, even if it made for a fascinating look inside one of these very chonky USB chargers.

Continue reading “Fault Analysis Of A 120W Anker GaNPrime Charger”