- I wanna find out
what's the fastest I can charge an iPhone,
even if it means getting pretty crazy.
This is an iPhone 8 with a brand-new battery.
It charges from empty to full in around an hour
and 57 minutes using the fastest charger that I have.
So I wanna see what I can do to speed things up a lot.
I'm using an iPhone 8 because it was the first iPhone
with fast charge, and I'm planning
on breaking a whole lot of phones in this video,
so I didn't wanna spend the big bucks on the latest iPhone.
The first obvious thing to do
is to just add more chargers,
inspired by our friend TechRax.
This is 100 chargers,
and this is 100 cables.
And while I don't think this will work very well,
I gotta try it out.
(exciting electronic music)
(exciting electronic music continues)
Man, who thought stripping this many wires
would be this hard work?
(exciting electronic music continues)
Okay, let's give this a shot.
There we go.
It's turning on.
Hey, hey! It's charging.
Here we go. (air whooshing)
There we go.
That wasn't any faster.
(chuckling) In fact, it was a lot slower.
But according to the math,
since each one of these chargers can supply one amp,
I should be able to charge
this 1821-milliamp-hour battery
in the iPhone in a little over a minute.
So what's preventing that?
So I grabbed a second phone that's currently discharged,
and I'm gonna hook it up to my benchtop power supply.
Shout out to Keysight for hooking me up
with some cool test gear here.
Five volts. Yes.
And then it's already set to 10 amps,
which is the max for this circuit.
And it's charging. Okay, cool.
We are currently drawing almost one amp,
but you'll notice we're not drawing 10 amps.
So why, if the power supply can supply 10 amps,
why is this only drawing 9.6?
To show you why, I'm gonna have to take apart the phone.
(slick electronic music)
(slick electronic music continues)
All right, there is the battery.
Now, let's take this apart.
(thoughtful music)
There we go.
So this part here is the actual battery cell.
This is where the chemistry magic is happening
to store the electricity.
But this part up here,
you can see there are all these little chips.
This is called the BMS,
and this is the battery management system,
and it's responsible for a couple different things,
making sure that the battery doesn't get overcharged
or undercharged or overheat.
It also has something called the gas gauge,
which keeps track of how much electricity goes in
and out of the battery cell,
which tells you how charged or discharged the battery is,
and it actually talks to the rest
of the phone to tell it that.
The BMS is actually limiting that charge current.
I think the next step is to figure out how to bypass this.
So on the back side here,
these are where the tabs get spot welded on.
I wanna solder on a wire to each of these sides,
and I'm gonna run the risk of overheating the battery,
but it should be okay.
I've done this before.
We're gonna use some eight-gauge wire here.
Let's pre-tin this thing.
Gonna kinda tin this up flat.
Let me grab a piece of cardboard.
(thoughtful music)
That'll work.
That'll work. I'm gonna leave this right where it is.
But now we have two charging wires that bypass the BMS.
Tomorrow when it's light out,
I'm gonna take this outside and try
and charge it at a much higher amperage
than the BMS would normally allow us to.
This is a 90-amp four-volt power supply.
It's variable between about 3.5 and 4.4 volts.
I set it to 4.2, which is about the maximum
this battery should be charged at.
4.174. Good enough.
Needless to say, if it's not obvious,
don't try this at home.
(airy music)
I'm gonna go get a current meter here.
Five amps. It doesn't seem like it's volting at all.
A little warm, but not much.
It's, like, skin temperature at best.
Well, it's only charging at 1.5 amps.
It's really not much more than a normal charger.
I'm gonna stop it once it gets down to one amp,
'cause I don't think we're gonna see any fireworks here.
0.98. I might call it here.
Take this off.
Just being extra careful.
I don't just want this thing to explode on me.
I'm not expecting it. (airy music continues)
Put the battery in the bucket of sand,
just in case it has thermal runaway later,
inside a plastic bag just so it doesn't short out
from moisture in the sand.
That did not go the way I expected it to.
I expected to have a lithium battery fire.
So that's a 1.8-amp-hour battery,
which means it should charge at 1.8 amps,
would take an hour to charge.
You know, we started at maybe four amps
and came down past two, so you know,
had we kept charging it, I don't know,
probably take an hour, hour and a half.
But in my opinion, we can still do a lot better than that.
So let's head back inside.
I think we're done with the LiPo batteries,
but I have something else to try.
These here are lithium-titanate batteries,
and they're supposed to be one
of the fastest-charging types of battery chemistry.
So I've built a small battery pack
out of four of them to hook up to the iPhone here
that I've removed the standard battery from.
Actually, over here.
I've removed the stock battery
and I took the BMS off of it and just hooked up two wires
to where the cell would normally be.
And so this can plug in here.
This is a little step-up voltage regulator.
The max voltage of these lithium-titanate batteries
is only 2.85 volts, whereas a normal LiPo cell
in an iPhone is around 4.2, 4.3 volts.
This little voltage regulator
actually steps up to five volts.
The phone seems to tolerate that just fine.
I've got it set to 2.85 volts.
This maxes out at 10 amps.
These can be charged up to five amps each
so they're wired parallel.
20 amps.
We're gonna charge it at 10 amps
'cause that's what I've got.
Right here. One, two, three, go.
All right, charging at 10 amps.
Look at that. 26 watts!
(laughing) That's awesome.
Okay. This is way faster so far than a stock battery.
We can plug in the phone now.
So you can see the phone is reporting it's at 100% charge.
It's not at 100% charge.
It's just that the BMS has no idea what this is
and what voltage it should be at,
and BMS is pretty useless right now,
which is what regulates the phone's knowledge
of how charged it is.
We're gonna go off of how much current is flowing
into the battery for how charged this is.
Once it hits about 150 milliamps,
that's kinda what a stock battery will do when it hits 100%.
I'm gonna let this run for a little bit.
I'll be back with you shortly.
(air whooshing)
Okay, it's been around 21 minutes,
and we're getting very close to 150 milliamps,
which is what I said the cutoff would be
for considering this fully charged.
(air whooshing)
There we go.
Let's call it 22 minutes to fully charged.
That is not bad, to go from empty to full
on an iPhone in 22 minutes.
But can we do even better?
What if we don't use a battery at all?
This is a supercapacitor.
It can hold a little bit more than a normal iPhone battery,
but it can also charge super quickly like a capacitor,
and this one is a 5000-farad lithium-carbon supercapacitor
that has a max charge current of 47 amps, which is insane.
Remember, this charger is only one amp,
so to charge it at 47 amps, I need something much beefier.
This charger is 90 amps,
and I've hooked it up with two-gauge wire
and these beefy 175-amp connectors.
So let's give this a shot.
Here we go.
Okay, I think that's it.
Yeah, we're pretty much at 4.2 volts on here
and nine minutes.
I think I'll declare that. Good.
Wow, nine minutes. That's crazy.
That's 13 times faster than the stock iPhone.
Now, obviously this is a bit bigger
than your standard iPhone.
One of the downsides
is that supercapacitors are a lot less dense
in terms of energy storage,
so to store the same amount of charge as a LiPo,
they need to be physically bigger,
or to put it at a different way, a supercapacitor
that was this size would store about half as much energy.
So would you rather have an iPhone that could charge
in nine minutes but would only last half as long,
or how about an iPhone that would charge super fast,
last just as long, but was twice as big?
Ultimately, a lot of these product
and engineering decisions come down to trade-offs.
I'll be honest, going into this, some of the physics
and chemistry involved was a bit over my head.
It's not uncommon for me to need
to learn something new for one of my videos.
I'm always learning as I go.
So are all the best engineers and creators that I know.
And categorically, they all learn best
by diving in and trying to solve problems
and come up with creative solutions.
They don't just read a textbook or go watch a video.
But you need good problems to sink your teeth into,
which is why I love Brilliant so much
and why I'm thrilled to have them as a sponsor.
Brilliant is a tool for learning math,
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I love being able to just pick up my phone or tablet
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And the key is their learning philosophy that centers
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I turned to Brilliant to brush up on my chemistry knowledge
for this video using their chemical reactions course.
This right here is a problem about atom
and molecule concentrations
and how many reactions we can expect.
You know, look at the animation,
read sort of their text explaining,
and then they give you a quiz.
And so I'll say...
"How many collisions do we expect in the first moment?"
250. "Correct!"
Okay, so if I got that wrong
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to that answer, I can click on Show explanation.
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They don't have just chemistry.
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And if you wanna see more videos of me modifying phones
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or go watch my previous iPhone videos here
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I'll see you again soon.