Don Devices Explained Clearly

Someone from my team kept unplugging and replugging his laptop. How many devices have I killed and how many laptops have I murdered? Most of us don't put a second thought into our batteries, but our world runs on batteries and they have gone from this into dangerous, explosive, literal fire hazards. Like why can't we figure them out? can't bring those things in a public vehicle. Batteries? Yeah. The landlady in my old New York apartment actually banned e-bikes and scooters from the building. Does anybody even know what they're talking about? And if this 20/80 percent range is so important, why isn't it a feature

on my laptop? Where did all of these idiotic, but apparently life and death rules actually come from? Every video I found, every article I read, every Google search contradicts itself. So I don't want more Slack fights. I don't want to kill more of my devices. I wanted battery truth. So I've spent months obsessing over batteries, exploring lithium mines, dusting off knowledge from school about chemistry, and finding which of the myths about batteries that rule our lives today are actually real or just urban legends. All right, so let's start with the easiest. This is a AAA battery and nightmare to me.

Uh, this basically broke my economy as a 10-year-old, so I am getting some revenge today. And let's figure out if Charlie is right about that weird laptop babysitting. You know what? Hold on. I'm not sure how true this is, but let's set a It's a good example for the kids. Batteries rule the world. Now, the latest laptops are basically all battery. And honestly, a couple months ago, I had no idea how this stuff worked. Now, before we get into laptop myths, we need to understand what a battery even is because every bad rule starts here.

Okay, so this is the inside of a good old AA battery. The ones that I grew up using. In my imagination, this was positive and this was negative, right? That's not how it works at all. It's more like this shell and a cylinder in the middle. Now, this outer shell is made of zinc, which is like battery fuel. Zinc is an element that desperately wants to lose electrons, which are, you know, electricity. By the way, I promise I'm not going to put you through chemistry class for nothing. These things are the reason why you can't even fly with a power bank these days. So, just stay with me for 1 sec. Okay, so don't mind my drawings,

but uh let me draw an atom of zinc. It's going to look something kind of like this. So, the atom of zinc has 40 electrons floating around. So, the whole thing about how electrons are arranged, which I didn't pay enough attention in school, but there is a pattern to them. I mean, it kind of looks something like this. These two electrons that float around the zinc atom, they're kind of loose. They want to escape zinc. And now, we need this mix of elements in the middle that loves eating those electrons. And that's in essence what a battery is, right? A mix of one material that sheds the electrons, again, the electricity, mixed up with another material that likes receiving those electrons. But, if you just connect

those two things together, then this battery is going to short, and it could actually blow up. Now, we paste the movement of these electrons to the other side with literal battery acid. And the acid is here. It's in this paste that's between the zinc and the core of the battery. By the way, we're going to have to put some proper names into all of this. The zinc in this battery, so this outer shell, that's going to be the anode. And this positive end, like this mix of things in the middle, this is going to be the cathode. And then this part that exists in the middle just for them not to touch each other, this is going to be called the electrolyte. Now this electrolyte is kind of like a bouncer at

a club. It completely blocks electrons from crossing the inside of the battery, and then the only way for these to get from the anode to the cathode is if you plug your battery. Now that's why cutting these batteries is a bad idea because the saw creates a bridge between these two, a bridge between the positive and the negative side that shouldn't really exist. Now the electrolyte in the middle, that's what let you make those old-school projects with fruit batteries. So ChatGPT originally recommended using a potato, but then Gemini recommended using lemons. And I'm I'm making a mess of all these tools cuz I use Gemini for search and Claude for coding and GPT to summarize, and I've been paying like

$20 for each one of them. It's ridiculous. So when Mammoth reached out to sponsor this video, it was perfect timing cuz they built exactly what I needed. Mammoth is basically a single hub for all the best AI models. So instead of paying for five different subscriptions, I just pay 10 bucks a month and I get access to Claude and GPT and Mistral and Grok and Deep Seek and Perplexity, even image generators like Flux and Recraft. There is no vendor lock-in, and whenever a new model version drops, they update it right away. So the feature I actually end up using the most is the document analysis with this side-by-side re-prompting. So if I'm trying to make sense of a huge financial model or some huge PDF, I can

upload the document, run the exact same prompt through different models at the same time to compare their insights, and it saves so much time, man. Now because I'm uploading sensitive data, the privacy aspect for me was a non-negotiable. Now these guys are a European company. They're based in Paris, which means they're very strictly GDPR compliant. They have zero data retention. Your prompts, your privacy documents, they're never used to train the models, which is a massive deal. So, if you want to stay on the bleeding edge of AI without burning a hole in your wallet, go to mammoth.ai. Link in the description or use this QR code here to try it for 10 bucks a month.

It's zinc. And now, on the positive side, something that likes to eat electrons like a penny. And now, for the moment of truth. Man, if this doesn't work, my entire video just goes to So, there should be a negative current that comes out of the nails that goes to the positive side, which is the pennies, and the electrolyte, which is the lemon juice. No way. Yes, science. Now, the battery acid has another job, because when this zinc in the outside of the battery loses those two electrons because you're you're playing some Game Boy, right?

It's going to become positively charged. It's going to become zinc plus two, right? Because it lost two electrons. This is called an ion. That's an atom that has a positive charge. These ions of zinc, they like to dissolve in the battery acid. But there is a native fatal flaw with this system. Did you catch it? For every two electrons that the zinc wall loses, one atom, really technically an ion of zinc, it actually becomes part of the battery acid. Zinc goes from being the solid metal that encases the battery into a dissolved ion in the acid paste. So, we arrive at the flaw.

Zinc in these AA batteries is the battery fuel, but it's also the battery walls. And as you use the battery, the shell of the battery is basically eating itself. The walls get thinner and thinner as the battery gets used until you get your favorite toy ruined because the battery leaked. The battery walls were literally eating themselves away. I can't count how many toys I lost to this. I had no idea why. Now, there was of course no recharging on these batteries cuz again, the zinc wall was just gone. It was eaten away. Now, obviously, none of this explains Charlie's laptop. Yeah, like nobody's putting AA's in a MacBook, but this is where the first battery folklore starts.

Now, you might have read that AA batteries could explode if you charge them. Did we make that up? Not those old zinc batteries, but yes, to alkaline batteries, they could become little bombs, too. Now, one great thing that they did with these alkaline batteries was stop making the shell the power source. So, thanks for that. Instead, what they did is they put the zinc in here. That's the inner part now, and it's it's inside the battery as this pulverized powder. So, now there's more room for more zinc than the older zinc-carbon batteries, which means that there's more power that these batteries can generate, and there's no more zinc dissolving itself.

In an alkaline battery, actually, the zinc is not dissolving into the liquid. Instead, it's oxidizing. So, the battery depletes when all the zinc inside turns into rust. The real problem is when you try to recharge these things. When you add power into a depleted alkaline battery, the zinc inside the battery, it's not going to un-rust. It's it's already dead. So, this electricity that you're sending to the battery doesn't go to the zinc. It has to go somewhere. Now, instead, it goes to the electrolyte, which in these batteries has a little bit of water. And when you send electricity to water, what happens is electricity splits those water molecules in the electrolyte into hydrogen and oxygen. And if you trap

those two in a metal cylinder, So, alkaline batteries do explode if you try to recharge them. That myth is actually very true. Again, like many of these myths, they have a solid foundation, but we've gone through so many types of batteries in our lifetimes that just nobody can keep track. Back in 1859, we figured the tech that gave us these. And this is where Charlie's fear of hitting 0% actually starts to make a little more sense because for car batteries, that fear is real. And in this case, the elements that powers the whole thing is lead. Now, lead is another one of those tricky elements, kind of just like zinc, cuz it has these four electrons on the outer range, and it also likes to give those away. So, that's going to be our anode. And on

the other side, on the cathode, we have lead dioxide, which is literally just rusty lead. That's a material that wants to pull electrons in. Now, this electrolyte in the middle is acid. That's sulfuric acid dissolved in water. So, this is the acid part, and this is the H2O. Now, when you pull energy, aka electrons, from the battery, you start your car, then you have these electrons, of course, flowing out of the negative side. So, what that does is that makes the sulfate, the sulfate that's in the acid, attach to those lead plates, both in the anode and the cathode side. Now, as that sulfate sticks to these plates, the acid, like the liquid in here, starts to get weaker and weaker until what we have left is

really just mostly water. But, here's the magic trick. When you run the engine and you start pushing power back into the battery from the alternator, the engine running, this sulfate gets back, like it's removed from the plates. Now, that turns the watery bath back into battery acid and boom, you've you've made this thing rechargeable. Now, this is the principle of rechargeable batteries, a reaction that we can reverse when we plug some electrons back into the system. But, we all know too well that car batteries aren't perfect. My '91 Corolla taught me that lesson all too well. First, growing and shrinking that crust every single day makes those metal plates brittle and these chunks of lead start falling to the

bottom and they become this sludge. But, the biggest problem is that if you leave your car battery dead for too long, say if you leave the headlights on for a few days and forget about it, those plates, they're going to be covered themselves completely in this crust of sulfate and it's going to stick there. Now, that myth about not draining your battery completely is very much true for car batteries because that sulfate hardens in the cells and once it does, there's there's no way to remove it. And even when the battery is running normally, the sulfate uncrusting process isn't perfect. Every time you start your car, just a tiny bit of those crystals, they get stubborn and they refuse to dissolve back into the acid and that's

literally what eventually kills. And there is very much a bomb potential on car batteries as well. Now, because there's water and electricity mixed up in here, just like with an alkaline battery, that water plus electricity gets split into oxygen and hydrogen and we know what those can do. But, when you mix 100 years of battery technology, decades of different adjustments to that technology, well, you get a fair share of myths that your parents probably passed down to you. Some of those myths don't make any sense, like for example, never leaving a battery on a concrete floor or like putting dead batteries in the sun to bring them back. But, some of those tips actually could save your life.

I know if how much charge there is in there. Okay. So, you've probably seen these sparks when these clamps touch the battery or the car. That part is normal. The problem is that dead lead-acid batteries, they're venting hydrogen gas. And then sparks plus hydrogen gas is exactly how you end up in the news. What you want to do if you're doing any of this is that you want to plug the red positive cable to the dead battery first and then to the good battery. You might get sparks on this, but this is the hydrogen-free side of the car, right? So, you're plugging here first and then if you get any sparks on the other side, that's

fine cuz that car has no hydrogen around it. And then you plug the black cable on the good battery so on the other car again, sparks could be possible. And then the negative side of the cable, not to the battery, but to the chassis of the dead car, which is going to be wired to the negative side of this battery, but more importantly, it's going to be far from the potential hydrogen cloud in here. In the very middle of this whole video shoot halfway through understanding this stuff, I ran into a roadblock in my head like a mind's roadblock cuz we said that electrons, aka electricity, they're coming from the negative side.

They have a negative charge. So, why are we treating the positive side as this red active live wire? Now, believe it or not, this is easily the most successful wrong guess in science history and it's this guy's fault. Now, when Benjamin Franklin studied electricity, he knew that something was flowing from one side to the other and he tossed a coin, allegedly, and chose a side. And he chose that it was flowing from the positive to the negative. And for 100 years, we built electricity, we built a world around that guess. And by the time we actually discovered electrons in 1897, and realized that they were going the other way, it was too late. So, engineers just shrugged. They called Benjamin

Franklin's system conventional current, and we all pretend that electricity flows from the positive side to this day. Now, we know that the reality is different, of course, but it was just too much of a hassle to change everything. And this 250-year-old typo is exactly why for almost half a century cars were kind of like doomed to rust to death. Now, remember that the entire car is wired to the negative. It's connected to the negative side. But, it actually didn't used to be like that, funny enough. It actually used to be connected to the positive side. Now, this was a clever way to cut on manufacturing costs, cuz instead of sending two wires, one positive, one negative, to say the stop lights, the brake lights in the

back of the car, you could just send positive through the metal, and negative through the cables. But, because they wired the car backwards, they accidentally turned this entire chassis into the dissolving part of a giant battery. So, just like with our double A battery, the metal in the car started giving away atoms slowly when it reacted to like rain water and salt, and started eating itself alive. And for 40 years, cars rusted themselves to death at an accelerated rate just because they wired it backwards. And they finally fixed it in the '50s, and they flipped the wires. Chassis's became the negative, which is what we still have today. But, if car batteries taught us never hit zero, then the battery in my Discman actually taught me the exact opposite. And that

contradiction is exactly why Charlie's ritual is so confusing today. And I really remember these. I remember them because I remember they cost me like three or four allowances, and it went to waste. I remember my first part of nickel cadmium batteries, man. My Discman was no longer going to be a fixed expense in my teenager economy. In this case, it was cadmium, another one of those elements that's just happy to cough up some electrons. And compared to a car battery, that this felt like science fiction, man. This was small and light. There was no bucket of acid. We just had to ignore that fine print.

Consult your doctor before buying cadmium batteries. Side effects may include oxidative stress, cellular infiltration by importing essential minerals, disruption of DNA repair, irreversible kidney damage, increased risk of cancer, and weakened bones due to calcium mimicry. Do not ingest cadmium. Do not inhale cadmium. Do not ask cadmium to watch your kids. Stay the away from cadmium. But besides the tiny issue of cadmium being terrifying, these batteries had more problems. If you listen to your Discman and drained the battery down to 50% and then put that on a charger, the cadmium inside would literally grow crystals that forgot that the bottom 50% of charge existed. So, your battery permanently shrank to half of

its size just because you charged it without discharging it. There's a new rule for the board. Always drain your battery completely to 0% before charging. And for NiCd batteries, that rule was actually legit. And second, these nickel batteries, they were incredibly sensitive to overcharging. If you left one on a cheap wall charger overnight that wouldn't detect when the battery was full, it could just stop accepting electricity completely. Another rule that people still get confused about today, never charge your batteries overnight.

Are you seeing this mess? Half of our parents taught us to drain our batteries to zero. The other half taught us the exact opposite. And we've we've been dealing with these rules for decades and passing them down like absolute truth. Ultimately, these batteries were so toxic, especially as burned or shrunk capacity batteries started making it to landfills and then governments around the world actually got together, they stepped in and outright banned nickel-cadmium batteries from consumer gadgets. Now, their replacements, which are NiMH batteries, they're still around to this day. We use them in rechargeable double A's, in camera flashes, older hybrids.

Oh, but don't worry, they also had a list of problems. First of all, they hated being overcharged, but their most annoying talent was their self-discharge cuz NiMH batteries would sit in a drawer and slowly drain themselves. Sometimes they lost a huge chunk of the charge almost immediately, and that's why your digital camera was sometimes dead exactly the moment you needed it. Now, tech hit a wall here. We wanted electric cars during the oil crisis in the '70s, and actually companies tried. We wanted smaller phones, we wanted laptops that didn't feel like checked luggage. You know, phones looked like this, laptops looked like this, and we

were stuck in this thing, but none of these battery chemistries could actually get us there. But slowly brewing over 20 years, three scientists from different parts of the world, each one stumbled upon a discovery that together very much transformed This place where I'm standing, the driest place on Earth, is the actual most valuable plot of land in America. That site behind me made $9 billion of revenue in 2022, and there could be trillions more buried under this soil. The lithium triangle in South America has more than half of all the lithium in the surface of the Earth. It transformed the economy of Chile and other countries that were blessed with lithium deposits.

Lithium is so light, and lithium batteries can hold so much energy that they literally built transformed the modern world. Without lithium, there wouldn't be any smartphones, there wouldn't be any thin laptops, there wouldn't be any drones, there wouldn't be any electric cars. Lithium is actually really good for batteries. It's at the very top of the periodic table, which means that it's ridiculously light, and it has this only has only three electrons, but it has this one that's so loose. It's just

it's just dying to leave this atom. There was just a bit to solve here because pure lithium is like insanely unstable and basically a It took us a year to control it, but we did. Or I mean, these guys did. And their solution was Well, was worth a Nobel Prize. I'll bet you a dollar that the battery that's inside your phone or your laptop or the tablet where you're watching this is a lithium battery. By the way, if you're watching this video on a TV, just don't forget that the subscribe button is in a different place. It But, you know, subscribing helps keep these documentaries awesome and human-made and free. But anyway, here is how these guys solved it. So, instead of using pure explosive lithium, they strip lithium

down into these lithium ions. And they built a battery where those ions, they'd be floating safely back and forth in the electrolyte. Hence the name, lithium-ion battery. Now, remember those zinc ions that were plus two and got dissolved in the battery acid? It's kind of the same idea here. Lithium ions are plus one cuz they've lost that one electron. And now, well, now they can move across this battery without this whole thing exploding. Now, on the negative side, that's going to be the anode, we have graphite. And on the positive side, we have this metal oxide, usually something like cobalt oxide, that's going to be the positive side, the cathode.

Now, think of both of these structures kind of like a garage. So, when the battery is full, what happens is most of those lithium ions, they're going to be parked on the graphite side. And once you start using the battery, electrons are flowing around here through your devices and whatever, these lithium ions, they leave the graphite side, they move across the electrolyte and over to the cathode side where they get parked instead. When you charge the battery, the opposite of that happens. They move back to the anode side. Now, the big magic difference with these batteries is that these reactions, they're just insanely efficient. Like practically all of the lithium ions move back and forth every time cleanly over

and over again. There's no rust, there's no crust building up on the plates, there's no memory effect, and a chip inside the battery even stops it from overcharging and turning itself into a bomb. There were so many breakthroughs packed in this battery that when Sony released it commercially in camcorders in the '90s, all those devices that we thought were never going to be able to build, suddenly became possible. I joined the industry when lithium ion cells were first introduced. There was a Sony camcorder that was introduced. 8 hours of run time, so they had an advertisement in a magazine. It was eight pages long. Each one was an hour longer, so it was a big deal.

And this is the battery inside Charlie's laptop. So, if his weird 20 to 80 ritual means anything at all, well, the answer has to live here. I get it. Like Charlie probably has decades of trauma from dangerous, inefficient, quirky, toxic batteries. And he brought all that trauma with him. Like lithium doesn't truly care if you charge it from 50 or from 80 or from 10%. It doesn't grow jagged crystals that forgot their capacity. It doesn't slowly leak its charge into the air while sitting in a drawer. It doesn't

need to be completely drained to zero. It even has a built-in microchip to stop itself from cooking to death when you leave it plugged in overnight. We can finally erase this stupid whiteboard. There are problems with lithium batteries, too. Lithium batteries didn't kill battery stress, they just changed what stress looked like. The biggest problem with lithium batteries is this thing called chemical stress. When you slide billions of these tiny atoms in and out of these microscopic garage metaphor that we've been using, when you do that thousands of times, that garage, that structure starts to break down.

And this is a lot worse when the battery hits extremes. For example, when you plug your laptop or your electric car and you charge that to 100%, you're actually forcing all the lithium ions back into this graphite garage thing on the negative side. And it can absolutely handle it. It is what it was built for. But if you leave that at 100% all the time or for extended periods of time, like leaving your laptop plugged in your desk 24/7, yeah, you are keeping that parking garage like overstuffed, stretched, and under maximum pressure. That puts actual tension in the structure, and over months and years of that constant tension, the layers of graphite degrade. So, yes, these parking spots are

colliding, they're crushing the lithium ions. They're trapped forever, which means that your battery holds less and less of a charge. Now, for your laptop or your phone, which only is actually useful for a few years, it's usually fine. You can change it, it's cheap. But this is what absolutely murders the resale value of electric cars, where a battery is worth like half the price of the damn car. The exact same problem happens if you let your device die and you don't charge it right away, cuz the cathode side, it's a structure just like the other one, right? So, it's getting stuffed at 100% with these ions, and it also starts

breaking down. But that gets actually worse, cuz as this internal structure starts to crumble, the liquid in the middle, the liquid in the middle paste where the ions travel through, that also starts to chemically decompose and starts to release gas. And because that gas has nowhere to go, gets trapped in the sealed battery and it starts to swell. Now, this is bad on the 100% charge, but on the 0% discharge side, plugging that battery back can short circuit and kill it. And then many batteries even have this tiny circuit board on top. When the battery detects that it's been dead like at 0% for too long, that little chip permanently bricks the battery. It actually unalives itself and refuses to ever accept a charge again. So, have we

even solved anything? Did we just replace every old battery problem with a new, more expensive battery problem? It's a little dramatic, but this chart is probably the best proof that we did solve something. This is the price per kilowatt hour of battery power. We've brought that down from well over a thousand dollars per kilowatt hour into the low hundreds. And then here's this other chart that matters even more, which is the energy per kilogram. So, in other words, how much battery you have to physically carry to get a useful amount of power. Now, we went from batteries that were so heavy that only made sense in cars to batteries that are light enough to build laptops and drones that actually fly while carrying this battery, laptops, electric cars around. This is not a

minor improvement. That's a technological regime change, all thanks to this lithium. But when that stress turns physical, that's when it becomes a headline. Cuz lithium batteries, they actually make great A failing lithium battery is actually terrifying because it brings everything that a fire needs. It has the heat, it has the spark, it has the fuel, and it even has the oxygen. Most batteries, of course, will never fail like this. But there are so many of these batteries now that they're packed into every phone, into every scooter, laptop, e-bike, and car, that these rare failures they're turning into very real fires that we are bound to come across eventually. UL estimates that thermal runaway happens in roughly one out of

every 10 million lithium-ion cells. Now, one battery may have multiple cells. Now, that still sounds like very, very far odds, but again, we have billions of these batteries everywhere now. Now, the classic failure point is that the microscopically thin separator between the anode and the cathode, that's only supposed to let lithium ions pass on each side, breaks down. Maybe bad manufacturing or a defect or hard hit maybe tears that layer, and then the electrons take a shortcut through the battery. Now, the battery dumps all of its energy, it gets insanely hot, the electrolyte catches fire, and that's why my old landlady banned e-bikes. Not because

lithium is evil, but because a badly made or a badly damaged battery can really, very realistically through on the board, turn itself into a feeding fire. So, let's please stop pretending that all these batteries are the same. Drain to 0% before charging, that works for 1997 camcorder. Never let it plugged in overnight, it's great advice if your phone runs on an old nickel chemistry battery. Never let it hit zero, well, that still works for car batteries. The 20 to 80% rule, it's helpful in theory, but modern laptops already know that. Now, specific to lithium, does fast charging ruin batteries? It doesn't really. What affects these batteries is heat, and when you fast charge, yes, the battery gets hotter, and that heat actually

stresses the battery. It breaks down the little garage structure thing. But, the charger is not the villain, it's the temperature. Now, does overnight charging kill batteries? No, because modern lithium devices, they're smart enough to stop themselves from overcharging. Your modern laptop can stop charging the battery, protect it, and just power itself from the wall. So, finally, who was right about this? Like, Charlie was there like battery managing his battery like it's 1997 and meanwhile Apple and a bunch of other manufacturers they actually fixed the thing. In a Mac under settings battery charging you can change the Mac's battery setting to 80%.

I had no idea about this. For some reason Apple buried this solution under like a menu that doesn't even have a button. It's like the little I thing but yeah so Charlie was wrong because when he unplugs his laptop and lets it drain he's he does wear out the battery by you know moving these ions from one side to the other forcing it to drain when the computer could have just been running out of the wall. I was wrong because yes my laptop has been sitting at 100%. I usually use it plugged so it's been at 100% plugged for 2 years now so yeah probably shaved some life out of it. But the point of this whole video wasn't to have you memorize all these thousands different battery rules. The

point was to have all of us understand that we've lived through so many eras of battery rules that so many of our rules today just come from a completely different era. We just didn't inherit [clears throat] battery knowledge. We just inherited the folklore. But now hopefully we all know better. Now if you enjoyed this video we made an awesome video about smart homes. Like I obsessed over building a smart home and why it's been impossible so far and I actually think I found the solution. You should check it out. Thanks a lot for watching.