My car charger can boil water really fast [video]

He mentions induction 'hot plates' towards the end, and says that they're limited to the same 1800W and 120V as kettles, but there are "commercial" portable induction stoves that are 220V and can go up to 3500 and 5000W; e.g.:

* https://www.vevor.ca/induction-cooktop-c_10592/vevor-portabl...

* https://www.trueinduction.com/Commercial-Single-Induction-Co...

Just need a NEMA 6 plug (GFCI/AFCI per code as well probably):

* https://en.wikipedia.org/wiki/NEMA_connector#Nomenclature

In the US. In the UK 2200W induction plates are readily available with a standard plug for ~£40, or if you spend a little more you can go to 3kW - [0] which is about the limit of most domestic circuits but is hotter than most gas hobs.

If you _really_ want more than that you can go a little mental and use one with an integrated battery which can push out 10 kW [1]

[0] https://www.nisbets.co.uk/nisbets-essentials-single-zone-ind...

[1] https://www.impulselabs.com/

This begs the question, and I've genuinely thought this before, of why we don't just strap a battery to a kettle and end this silly debate. If it takes 5 minutes to boil a cup of water in a 1000 watt kettle, that's somewhere around 80Wh... I guess it would be kind of expensive, but couldn't you make a pretty fast kettle with some number of high discharge battery cells?

(Well honestly, I guess the real answer is outside of Internet debates most people probably just don't consider 5 minutes to boil a cup of water to be a problem.)

It would turn an inert device that costs a couple bucks to manufacture and has affectively no usage limit into a bomb that costs a couple hundred bucks (due to lack of economy of scale) and is limited by the battery's rated number of cycles. The battery's proximity to the heat source wouldn't help.

People that care about the time it takes to boil water just have an instant hot water boiler on (or under) their bench.

Impulse Labs is doing exactly this..

I believe there master plan foresees a future where batteries are more integrated with a house for decentralized grid storage. But the additional consumer advantage is better hardware - i.e cooking time.

If people are willing to rewire their homes for kettles, I guess a couple hundred bucks isn't that bad.

> limited by the battery's rated number of cycles

Obviously the battery should be replaceable. (It should be in most electronics, really...)

> The battery's proximity to the heat source wouldn't help.

That doesn't seem like a particularly tricky problem to me. The standard kettle already tries as hard as possible to insulate the heat. If you were really worried it'd be possible to put the battery on a separate power brick instead probably.

...

And I guess I could've solved my own problem by googling it. There are tons of battery kettles on the market, including a 1500W one by Cuisinart and a 2200W (apparently?) unit by Makita. The latter is predictably expensive but the Cuisinart is available for around $100 where I live, which is definitely pricey but seems plausible.

It's probably just the price of batteries. You can definitely do this and you'd need like 8 18650 batteries, which today you can get on amazon for $30 USD. A decade ago it might have cost $200-$300.

Given that premium kettles already sell for about $100, there's definitely room for an ultra premium kettle that boils water laughably fast for $150.

Sure, but over in 230V-land 3500W hot plates are completely standard, and can plug into any regular wall socket. Same with microwaves and hot-air ovens: just put it anywhere on your kitchen countertop and plug it into the nearest socket.

We do also have a "kitchen plug" for high-powered appliances. Those go up to 7.3kW in their regular dual-single-phase 16A version, 11kW when wired with three phases (quite common in households these days), or even 17kW with the (understandably) rarely-used 25A plug variant with three-phase wiring.

And that's not even commercial equipment, just what you'd pick up at your local Best Buy equivalent. The commercial stuff uses CeeForm, which is a three-phase 16A/32A/63A/125A plug. Or it's getting hard-wired.

That seems a terrible waste of batteries to me. A boiling water tap seems like a better idea to me - electric heater with a pressurised insulated vessel that just dispenses from your tap.

I swear Vevor makes everything.

What is the specific standard for domestic 16 A and 25 A 3-phase plugs you’re referring to?

> Obviously the battery should be replaceable. (It should be in most electronics, really...)

This is super wasteful when we can just hook up a heating element to an insulated tank and keep it hot like Quooker [0] does. Assuming the 3L tank, that would mean probably 20 minutes to heat the tank if it's entirely emptied for the US, but that's how long it would take to boil that water with an electric kettle _anyway_. If you want 5l of water for cooking, you cna use your 3L tank and fill it up with the "slightly lukewarm water that keeps coming through the tap", and then put it on the hob _anyway_. In the best case you're boiling 2L of water instead of 5 anyway.

> That doesn't seem like a particularly tricky problem to me. The standard kettle already tries as hard as possible to insulate the heat. If you were really worried it'd be possible to put the battery on a separate power brick instead probably.

Dunno what kettle you're using but no kettle I've ever used has been insulated. They're either plastic, or stainless steel. They do usually have a lid, which helps.

[0] https://www.quooker.co.uk/tanks

Not OP but - I can't answer the specific regs, but 16A/240V is absolutely bog standard for the UK and every high street store stocks ovens that will draw this down. They need to be on their own circuit, e.g. this [0].

I've never seen a single oven pull more than this, but devices like [1] are fairly common where you have two independent ovens in one, and it can pull 21A - this would necessitate the 25A supply.

As for three phase - https://www.howdens.com/-/media/howdens/assets/clh_asset_pro... this hob (which I have) will take 3-phase 16A, or single phase 32A. I've not come across any 32A 3-phase devices for home usage, though.

[0] https://ao.com/product/b54cr71g0b-neff-n70-slide--hide-elect...

[1] https://www.smeguk.com/products/DUSF6300X

I'm in the midst of a kitchen remodel (in 120V land).

I decided to pull an extra 240V line to the countertop explicitly for a tea kettle, which I have not purchased yet but seem to be available from Amazon UK for ~2x the price of an ordinary US-market kettle.

The most disappointing thing so far is the short list of kettle options that ship from the UK to the US.

Also not sure if I should get a UK receptacle (this would probably offend the bldg inspector, so I might swap post-inspection), or just rewire the kettle itself with a standard US (240V) plug.

FWIW, the extra wire + breaker cost was about $100. I expect to pay another $30 or so for the receptacle or appliance wire, and a bit over $100 for the kettle (and its replacements every few years). Not the least expensive option, but not too bad.

It doesn't have to be insulated like an insulated water bottle or anything, plastic is good enough for this. I have a cheap 120V kettle, nothing special, probably mostly plastic but with some superficial bits of stainless steel. After bringing a cup of water to a boil you can safely touch the base and anywhere on the kettle itself; there's not even an obvious sign of warmth anywhere except for the lid. If you don't believe me, I do have a thermal camera, but I assume this can be reproduced with most kettles, since it's not like mine is anything special.

Also: a hot water tank is just another type of battery. If it's really well insulated, it might work pretty good, but the self-discharge rate is probably still a lot higher than a lithium ion battery. If you aren't using boiling water every day this seems like it would be very wasteful.

I don't see anything terribly wasteful about the concept of putting batteries in a few more things. They're very recyclable, and already extremely abundant. It's not necessary, but neither is pushing several kW through a kettle just to get water to boil a bit faster. So really, that might be worth interrogating first...

The molded, sealed plug of a UK kettle would fare much better in a wet kitchen environment than an aftermarket plug you'd manually install (moisture can get inside and corrode the terminals and connections).

Personally I would just wire some NEMA 240V outlet and then have a separate adapter with a pigtail of that receptacle type and a workbox with the UK receptacle. It's a little unwieldy, but it puts the questionable hackery outside the realm of the building inspection at least.

Whether it's actually safe I though, that I am curious. Obviously the kettle can get the 240V potential it expects, but the neutral is center tapped out of the split phase transformer, right? Not sure how people wire this. (Doesn't the neutral wind up having to be one of the hots instead?)

No need to rewire anything - just get a universal plug adapter for NEMA 6-15P (or whatever your kitchen outlet is going to be) from Amazon, plug it onto the UK plug of your kettle, and Bob’s your uncle. (The building inspector doesn’t need to even see your kettle and plug.)

I agree. If I replace the wire, I'd get an assembly with the correct US molded plug (NEMA 14-30?), and perform the wire replacement inside the kettle itself. Your reason is good, but I'd do it that way for the aesthetics alone. :)

Hmm, yeah! I hadn't thought much about the differences between UK and US 240VAC service.

In the US, it's 240V 60Hz, split-phase with center-tapped neutral, and an independent ground wire.

In the UK, it's 240V 50Hz, single-phase with independent neutral and ground.

Frequency difference should be within design tolerance. and if my EE memory serves, the phase difference should be acceptable -- just measured from a different zero reference point. The neutral from the wall would be unused, and the ground would be wired as usual.

I'll think this through thoroughly though, I was definitely glossing over those details, so thank you!

That does sound like a much better idea, thank you!

The only one I found that was truly battery-powered was the Makita [0]. The $99 Cuisinart I found seems to be a standard electric kettle. Lots of kettles describe themselves as cordless but that does not mean battery-powered; it just means the kettle itself can be removed from a corded base.

I also found a ton of AI-generated link spam pages purporting to be about battery-powered kettles that are all clearly not battery-powered (e.g. [1]). Some of these are 12v powered, but they still contain no batteries. Apparently the adjective cordless confuses AI just like it does people.

Side note: Boiling water takes a lot of energy. You need a big battery; not just a couple of AAs. Any truly battery-powered kettle is going to require a battery at least as big as one for a contractor-grade power tool, and that battery is going to deplete after roughly one boiled pot.

[0] https://www.acmetools.com/makita-40v-max-xgt-hot-water-kettl...

[1] https://activegearreviews.com/best-battery-powered-kettles/

Basically my concern is, ordinarily the potential from neutral to ground would be roughly 0V with some slack. In this case, though, the potential from neutral to ground would necessarily be 120V. I have no idea what the implications of that may be, but it seems important.

I think it works if the US neutral is left unused (terminated in the electrical box).

E.g, something like this:

  (US proposed)    (UK kettle)     (UK standard)
  (2-phase)      ┌─────────────┐   (1-phase)
                 │             │
  L1 120V 0° ────┼─ Hot(240V) ─┼── Hot 240V 1ph
                 │             │
  Neutral ───X   │             │
                 │             │
  L2 120V 180° ──┼─ Neutral ───┼── Neutral
                 │             │
                 │             │
  GND ───────────┼─ GND ───────┼── GND
                 │             │
                 └─────────────┘

I think this is right, but I'm not 100%. The kettle should get what it needs, but I'm less certain whether a GFCI or ArcFCI breaker would have opinions that must be accounted for. I'll check with someone more qualified than myself to be sure!

Yes I understand. But what I'm saying is, normally neutral and ground would have roughly 0V potential, but in this case the UK neutral and UK ground will have 120V potential between them, because the US 120V second phase will have 120V potential to ground. (It bears noting that I am just a random guy and not any kind of expert. No formal education or credentials relating to electricity whatsoever.)

I think you're thinking about it on the kettle side, and I was thinking on the breaker side.

I think the kettle side would not care. It may be a ground fault in UK wires, but the kettle has no reason to detect it, and nothing sensitive enough inside to care. If I'm wrong, I'd expect to know shortly after starting the very first use. :)

You guys know he talks about this 4 minutes into the video, right?

See also: https://diy.stackexchange.com/a/315031

Err, well, from the title, I expected it to be a garage experimentation video without practical information. Thanks for the correction. :)

Video was published last week and reaches the same conclusions as this thread. Timely, and reassuring! Thanks for the SE link too.

Perilex.

Go for a German kettle instead of a British one. Schuko wall plugs are reversible, so there will be no assumptions about neutral vs. ground.

Both live and neutral wires have to be treated as if they were both live, because 50% of the time they'll be swapped around.

I watched the video already before this HN thread, being a Technology Connections subscriber, but I genuinely forgot or missed that it discussed that aspect. I'm not surprised, though.

It's a Chinese reseller, with some quality control maybe but surely some great service attached to it. But you'll find 90% without vevor Logo on AliExpress.

Still big fan and regular customer, very surprised to see they have a .ca too and likely more.

I've seen those around, even with an integrated carbonator to get sparkling water right from the tap. They're neat but also ridiculously expensive

> It doesn't have to be insulated like an insulated water bottle or anything, plastic is good enough for this.

Yeah I agree, but I was responding to the point of: > The standard kettle already tries as hard as possible to insulate the heat

Which isn't true at all. They make a token effort.

> Also: a hot water tank is just another type of battery.

You're technically correct, the worst kind of correct.

> don't see anything terribly wasteful about the concept of putting batteries in a few more things. They're very recyclable, and already extremely abundant. It's not necessary, but neither is pushing several kW through a kettle just to get water to boil a bit faster. So really, that might be worth interrogating first...

It takes ~320 kJ of energy to bring a litre of water from room temp to boiling, no matter what way you spin it. The difference between pushing 1500w or 3kW into the hot plate is "how quickly do you get to boiling", and has basically no bearing on the total amount of energy used to boil the water. Running a 1500w kettle for twice as long will use the same amount of energy, from the same source.

Using consumable li-ion/alkaline batteries to supplement that energy is _terribly_ wasteful - we've been through the "reduce reuse recycle" loop already with waste, lets not do the same thing with rare earth metals to avoid running a single cable to household appliances.

One thing in that thread;

> Most UK kettles are not 3000W, and most of the ones that are, are junk. Y

They may not be 3 kW, but even the most basic of them are 2200W [0], and 3000W ones are readily available are not much more expensive [1]. They're also not really junk - they're a lump of plastic, a hot plate and a thermistor - the difference between a £8 one and a £80 one is almost all aesthetics.

[0] https://www.argos.co.uk/product/3102039

[1] https://www.johnlewis.com/john-lewis-kettle-1-5l/white/p5523...

> Which isn't true at all. They make a token effort.

Look, the point was whether or not it would be okay to put batteries on it, not whether it would keep a drink warm for 12 hours. If the base is cool to the touch, I think it will be completely fine for batteries to be near it. If anything, making sure they're safe from shorting is probably a bigger concern.

> You're technically correct, the worst kind of correct.

The point wasn't to be technically correct, it's to point out that you can compare the properties of the two types of batteries like-for-like and realize that for many people interested in a faster kettle the boiling water tank idea might not be great. In America most homes have a water heater and it has to contend with the same sort of problem, only we use hot water multiple times a day every day (and at least in the Midwest, use LNG for heating it a lot of the time, which makes it economical if not particularly environmentally friendly.)

> It takes ~320 kJ of energy to bring a litre of water from room temp to boiling, no matter what way you spin it. The difference between pushing 1500w or 3kW into the hot plate is "how quickly do you get to boiling", and has basically no bearing on the total amount of energy used to boil the water. Running a 1500w kettle for twice as long will use the same amount of energy, from the same source.

Well duh. My very first post in this thread is estimating how much energy is required for a typical kettle to bring a U.S. cup of water to a boil. (Though obviously in reality you have to account for losses.)

My point here is that (a relatively small niche of) people are already doing crazy things like rewiring their houses (in America) to push pretty absurd power into kettles just boil water slightly faster, a time save that literally only even matters if you sit there and wait idly while the water heats up. The problem I have isn't that higher wattage kettles are somehow bad, it's that all of this time, effort and money for a time save measured in minutes is crazy. And it's the same for strapping batteries to a kettle or for keeping a water tank of boiling water too. I wouldn't bother with any of them, and don't. (But, as I opened this thread with, seeing how crazy people get over this, I do remain surprised at the relatively few battery kettles on the market.)

> Using consumable li-ion/alkaline batteries to supplement that energy is _terribly_ wasteful - we've been through the "reduce reuse recycle" loop already with waste, lets not do the same thing with rare earth metals to avoid running a single cable to household appliances.

I just counted and the room I'm currently standing in has 8 separate high capacity lithium ion batteries. We put batteries in our power tools, laptops, vacuum cleaners, tooth brushes, game controllers, wireless computer peripherals, air compressors, UPS units, the phone someone is currently reading this comment on, air dusters, garden lighting and certainly much more. Almost everything with electronics in it has batteries for something (if you inlcude smaller ones like clock batteries), and more often than ever, high capacity ones no less.

A battery operated kettle will forever be an expensive niche product, and it wouldn't even use that much battery in the first place. The environmental impact of all of those batteries would struggle to get to the level of 100 electric vehicles, and yet we are selling over 10 million of those per year.

Of all of the contrived and silly arguments, this is by far the most contrived and silliest of all of them.

https://www.quooker.co.uk/ - these are the only "boiling water" ones (as in 100 degrees C), but if you're ok with 98C, then you can get https://www.screwfix.com/p/swirl-danube-3-in-1-instant-boili... instead for 25% of the price.