5 ms·
Wireless power transfer system achieves 270-kilowatt charge
- fghjkloy 2y ago"ORNL’s system can achieve a 50% increase in state of charge within 10 minutes with more than 95% efficiency." 13 kW of heating for 10 minutes. It'll get toasty.
- Filligree 2y agoIn open air, it's merely really inefficient. Would still be like a campfire under your car.
- Tepix 2y agoSomewhat related: How unhealthy is it to wirelessly charge your phone (in flight mode) at night on your nightstand not far from your head? Have there been any studies?
- spacephysics 2y agoNow imagine doing this with an EV battery beneath you as it wirelessly charges from the ground. Lots of interest groups would benefit from keeping any dangers of wireless frequencies under wraps. Now if we start to ramp up to the sizes large enough to charge an EV battery, 1/r^2 isn’t going to be enough when you’re in the drivers seat https://thehill.com/opinion/technology/4437988-why-did-nih-abruptly-halt-research-on-the-harms-of-cell-phone-radiation/?nxs-test=mobile https://thehill.com/opinion/technology/4437988-why-did-nih-a...
- gorkish 2y agoThe health risks of wireless phone charging are massively more psychological than physical. As they will very quickly abut claims of electromagnetic hypersensitivity, most of the legitimate research in this area focuses on the mental health of those who hold such beliefs against the overwhelming lack of any measurable physical phenomenon.
- jsheard 2y agoThe concerns about the magnetic field may be bunk, but I had to give up using a wireless charger next to my bed because I could hear the coils making a ticking sound. Qi interleaves data with power so I assume the sound is the coils reacting mechanically whenever they interrupt the power to send a data packet instead. I found that some USB wall chargers emit a high pitched whine when used to power a Qi charger as well, even if they are dead silent when charging a device directly.
- gorkish 2y agoBeing able to hear the coil whine and finding it annoying is a fine reason to not like wireless charging. But I am pretty sure this is not what most people are going on about.
- jasonjayr 2y agoIs the ticking a function of a mechanical relay in a cheaper device, or the coil not being sufficiently glued down and moving as the magnetic field is turned off and on?
- jsheard 2y agoThe latter I think, I found the volume varied depending on how the coils were aligned. I'll give it another shot once Qi2 brings Magsafe-like perfect alignment to non-Apple devices.
- gorkish 2y agoThe sound comes from the windings within the copper coils vibrating due to Hall effect in the alternating magnetic field. Yes, the physical construction of the coil matters as to how much it would whine; tighter and more regular windings and appropriate potting/adhesives counteract the physical effects. The easiest mitigation, however, is to just use a switching frequency much higher than humans can hear. AFAIK the Qi standard supports the charger using anything from 80-300kHz and can vary depending on what the charger decides is optimum. Any audible coil whine from Qi would be attributable to harmonic mixing within the physical system of the vibrating coil. Also note that the coil whine could come from either the Tx or Rx coil, so you might easily eliminate it with a different charger that settles on a different frequency or has a better manufactured coil. But if the problem coil is the one in your phone, you might be hosed!
- deleted 2y ago[deleted]
- segasaturn 2y agoI charge wirelessly next to my head every night for the last 2 years (With wifi and bluetooth turned on) and sleep like a baby.
- giantg2 2y agoThere hasn't been a lot of longterm research. Effects will also vary by frequency, intensity, etc. Some frequencies can cause heating, which is a problem for some areas like the eyes. Some frequencies increase glucose metabolism for the cells affected. No idea what that does longterm, but theoretically, that could create an environment for cancer growth.
- e63f67dd-065b 2y agoClaims of electromagnetic sensitivity have been debunked. They show symptoms to fake EM devices, and don’t show symptoms to real but hidden EM devices, so it’s all in their head. It’s the nocebo effect.
- Synaesthesia 2y agoThe transfer was over a distance of 5 inches. I suppose it's marginally more convenient to simply park your car over a coil to charge it than to get out and plug it in, but is it really worth it?
- malfist 2y agoTypically I only plug in when I'm below 60%, if there was a coil, I'd be leaving the house every morning with a fully charged battery. There's probably also benefits for public spaces, and not having to worry about the plug type.
- the_sleaze_ 2y agoI'm imagining roads where cars charge at stoplights and the owner gets charged for the service at the end of the month. Same for parking lots.
- pixl97 2y agoI can imagine it, but all I'm imagining is car companies doing a poor job on the protocol security and I get a $10k bill for power at the end of the month because someone spoofed my car token.
- rasz 2y agoOnly if you can imagine all cars with <5 inch ride height and magical coil positioners carefully aligning coils without moving your car or the road beneath.
- the_sleaze_ 2y agoI'll take the bait. We don't need magical coil or car positioners, cars do a great job of moving themselves already. What we need is targeting. Similar to how automatic car washes work. Just a "move forward 6 inches .. 2 inches". Non-trivial but not an unacceptably high bar. Then you could have a dead simple dropping mechanism to lower a charger down to charge - only within <5 inches of the roadway. When you drive off it can just retract like airplane wheels. I actually like it more now.
- gorkish 2y ago"wireless charging" as a technology has been pretty baffling to me -- to make it even remotely efficient almost every practical consumer implementation uses some form of mechanical alignment and contact system. As long as you are resigned to do that, why not just use normal mechanical contacts instead?
- toomuchtodo 2y agoYou might be willing to sacrifice efficiency for the common interface and component degradation over time from repeated physical connection mechanics. For phones, and other small devices, it's a reasonable solution due to the current and energy transferred involved. For vehicles though, it does not make sense (imho) considering the currents involved, especially as we're approaching 4C-6C with new battery chemistries and management systems.
- pixl97 2y agoAnd the number of phone cables I've replaced, especially beside my bed is already out of control. Switching to cables that plug in at 90 degrees has helped a lot, but it's something that can still wear out quickly.
- tw04 2y agoBecause, at least when there are magnets involved for alignment, it's easier. I've never ripped a charger out of the wall by picking up my phone in the middle of the night and forgetting I had a short cable attached to my phone. Kind of like saying you don't understand why we ever had early keyfobs when you still had to carry a key to start the car. It's not about it being superior in every aspect, it's about ease of use.
- mrich 2y agoCan not recommend charging your phone all night wirelessly next to your head while you are sleeping.
- 2y ago
- poorman 2y agoI dove deep into this topic after reading your post and discovered something fascinating: electricity doesn't actually flow through wires in the conventional way I was taught. It's more about the electromagnetic field around the wire. This video explains it really well: https://www.youtube.com/watch?v=bHIhgxav9LY https://www.youtube.com/watch?v=bHIhgxav9LY
- Workaccount2 2y agoWhile true, don't get hung up on it, it's kinda like "I was always taught that computers run python, or javascript, or rust, but today I learned that it's actually all just 1's and 0's"
- cnity 2y agoThat is actually a super useful and important insight, because the bridge to get there means unpacking interpretation, compilation, and things like compilation targets and CPU architectures. Not saying you're wrong!
- Workaccount2 2y agoSure, the analogy I am making is imperfect. In reality, you can be a career electrical engineer and never once come across or need to know the true workings of electricity. The models we are all familiar with cover 99.9999% of use cases.
- jnsaff2 2y agoThis veritasium video was VERY controversial as it tries to make an edge case into the main thing and trick you. Also made me unsubscribe from his videos.
- poorman 2y agoInteresting, I guess I'll have to dig deeper. I definitely want to understand this better.
- 2y ago
- bnegreve 2y ago> over an 4.75-inch gap
- Workaccount2 2y agoThe most important thing here is the 92% efficiency and how "ideal" things had to be in order to achieve that. Wireless power transfer typically has an efficiency curve that looks like the Washington Monument - or a middle finger, on a chart. Off by a hair and your efficiency is in free fall down the sides. Alignment, distance, frequency, impedance, parasitics...pick a dimension and it's all FU charts. So I am wondering if they made a system that can actively dial all these in given a real world scenario, or if they hand placed everything to ensure perfect alignment on all fronts, then took an efficiency measurement. Edited to add: A neat fact though is that when you dial in all those parameters as near to the ideal as you can, you actually can get over 99% efficiency. These are what transformers are. The electrical things, not the AI models.
- malfist 2y agoThis can be managed like an induction stove. Many small coils instead of one big one. Small coils outside the optimal position just turn off. Much like an induction stove can detect the pot size
- Workaccount2 2y agoInduction stove coils just need to induce currents above them in what is essentially a giant shorted out single turn secondary. Which is basically useless, hence why it just makes heat. Granted, it is useful for cooking! Wireless power transfer on the other hand needs carefully aligned coils in order to avoid doing exactly what an induction cooker does - turn usable electricity into heat.
- malfist 2y agoThere is no electrical difference between an iron pot that heats up from an inductive load, and circuit that takes that inductive load and directs it to chemical energy storage. The iron pot just doesn't conduct it anywhere useful
- Workaccount2 2y ago