Charge Your Apple With Apples

the full charger with gas tank and engine

When you think of ethanol, you might think of it as a type of alcohol, not alcohol itself. However, in reality, it is the primary ingredient in adult beverages. Which means humans have gotten quite good at making it, as we’ve been doing for a long time. With this in mind, [Sam Barker] decided to make ethanol out of apples to power a small engine to charge his phone.

The steps for making pure ethanol is quite similar to making alcoholic cider. A friend of [Sam’s] had an orchard and a surplus of apples, so [Sam] boiled them down and stored the mush in jugs. He added activated dry yeast to start the fermentation process. A dry lock allowed the CO2 gas that was being created to escape. Over a few weeks, the yeast converted all the sugar into ethanol and gas. In the meantime, [Sam] sourced a chainsaw and adapted the engine to run on ethanol, as ethanol needs to run richer than gasoline. The video below the break tells the story.

With his solution at just 15% ethanol, he needed to distill it to get pure ethanol for the engine to run. With a little bit of handwaving due to UK laws, [Sam] soon had a 94% ethanol solution. The next step was to use a molecular sieve, which absorbed the water but not ethanol. He secured the engine and generator to an old cutting board, and [Sam] was ready for the first test. Fine-tuning the right throttle and choke took a while, but [Sam] had it going consistently when he ran into a snag; the phone wasn’t charging. He revved the engine up, and his little charge regulator exploded. His multimeter probes were backward when he had measured the generator, and it was outputting a negative voltage. With the board swapped, the phone was charged. But [Sam] saw over 50 volts coming off the motor at times. So like most of here at Hackaday, he wanted to see how fast/high/far it could go. This ultimately fried the motor.

If you’re interested in modifying generators to suit your particular fuel needs, we have generators running on natural gas, ammonia, and even your own feet.

14 thoughts on “Charge Your Apple With Apples

  1. So many inefficiencies so much waste but it works. Bigger waste of alcohol. Loudest noise to charge a phone.
    A bicycle light generator is self limited to 300mA. AC to DC and some resistance, probably easier to rig up in a pinch without fireworks.
    50 years ago Soylent Green was set now. I like the scene where they take turns pedaling the generator for some light.

  2. Great stuff. I once met someone at a UK maker faire doing simular with 2 stroke mopeds, he was changing/adapting lots of the seals on the engines as he said ethanol was more corrosive. I wonder how long the set up in the video would survive.

  3. I make ethanol from the apples in my garden too, but for drinking.

    I don’t bother washing, peeling, and boiling the apples, though. There’s natural yeast in the skins, and if you don’t kill it on the way into the demijohn, that’s more than enough to get a good drink out of it. It’s worth buying a cheap fruit press to get the juice out of the apples, though. (A kitchen food processor will do the job of scrappling the apples into a mushy pomace.)

    1. For fuel ethanol the preference is for high alcohol yeasts. It reduces the amount of water you put in and the amount you have to distill back out. Still an excellent point; Natural yeasts work for fermentation too.

        1. Actually, why ain’t those part of the process, if it’s alcohol that poisons the poor yeasties to death, having it continually sucked out as produced would keep the wee yeasties alive and make for a semi-continuous process.

      1. There are yeast strains that ferment higher and also ferment faster. 12-17% in 24-48 hours yeasts were developed in the 90’s and they’re so fast you can’t put a bubble lock on the bottle because it just toots the water out and blows it up at the ceiling.

        It makes for terrible tasting booze, like drinking wet cardboard, but boy is it fast and strong.

  4. Why not KISS and connect apples in series (battery) to get proper voltage and multiple apple batteries in parallel to get proper current? And have they no Everclear in England?

    1. Hard to find anything over 100 proof .. ~62.5% .. apart from methylated spirits, and I hear tell that that is replaced by “meths substitute” in many hardware stores now… but that doesn’t use up waste apples.

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