Questions tagged [wireless-charging]

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4answers
8k views

How big does my wireless charging coil need to be?

Background: I need to wirelessly charge a battery at about 100W. However, there seems to be a gap in the wireless charging market. There are plenty of wireless power transfer systems operating in the ...
5
votes
1answer
129 views

Wireless Power Transfer for a toothbrush

The general idea is to charge a cordless toothbrush from 12V DC, instead of the mains. I have used a simple circuit that I more or less lifted from a Linear AppNote/Demo manual (DC1969). I would like ...
4
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3answers
10k views

How to build a self-made Qi compatible (wireless) charger

So I recently discovered that my phone, a Nexus 5, has Qi wireless charging capabilities. I was wondering if it is possible to make my own charging coil with 24/26awg wire that would look something ...
4
votes
1answer
130 views

Is it possible to redesign a portable electronic device such that it can be charged by a domestic microwave oven?

Soon after iPhone 6 was introduced there was a prank claiming that the smartphone can be charged by leaving it in a running domestic microwave. TL;DR don't do it, it is very, very unsafe. There's a ...
4
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2answers
89 views

What would happen if you accidentally casually put your apple watch on a wireless charger meant for phones or other higher power devices for hours? [closed]

What would happen if you accidentally, casually (because they're supposed to be so convenient!) put your apple watch on a wireless charger meant for phones or other higher power devices for hours? Or ...
3
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3answers
897 views

Using a capacitor instead of a coil for wireless charging?

This might sound like a stupid question, but I'm kinda interested in a detailed explanation. So while inductive charging is rather ubiquitous, things like electric toothbrushes and Qi chargers come ...
3
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2answers
171 views

How does the diagram really work? [closed]

Good afternoon, I am a high school student and in my scientific fair project, I would like to do an experiment about wireless energy. I want to implement the resonant inductive coupling. According ...
3
votes
3answers
2k views

Wireless Power Transfer at 50Hz

Is is possible to transmit power using magnetic resonance coupling at 50Hz? Assuming I have no constraints on the minimum distance between the primary and the secondary coil. However, the coils are to ...
3
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1answer
125 views

Do these waveforms look appropriate for charging an 11.4 V, 3830 mAh lithium ion battery?

I'm putting together a wireless power transfer based battery charger to charge an 11.4 V, 3830 mAh battery from the output of a 15 V voltage regulator I made. Due to a limited understanding of ...
3
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0answers
1k views

Qi Receiver on PCB

I'm looking at implementing Qi charging in my project, would it be possible to have a Qi receiver directly on the back of the PCB (copper traces in the shape of a coil)? Could this interfere with the ...
3
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3answers
157 views

Auxiliary circuit to reduce power losses in idle stage of this oscillator (wireless power application)

I am trying to implement the following resonant oscillator for wireless power transfer application. There will be a secondary coil coupled with Lp. . Reference - WPT Application Note One of the ...
2
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3answers
478 views

Inductor and capacitor for energy storage instead of battery

I am trying to see if it would make sense to use a LC network to store small amount of electrical energy (500 mWHr or less) as an alternate of a 3.3 V battery. What I understand is that L and C are ...
2
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2answers
1k views

Long range, wireless power transmission

What are the difficulties restricting the development of wireless power transmission over long distances? Could wireless power transmission be harmful and/or dangerous?
2
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1answer
321 views

why do resonant inductive coupling circuit operate at high frequencies?

Just as the title says. Whenever I read a research paper on wireless power transfer via resonant inductive coupling the authors just mention frequencies that range in the kHz and Mhz range, but none ...
2
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1answer
49 views

Can/will the Qi charging system damage LF (125-133kHz) RFID tags?

In the Qi standard, frequency is listed as 80-300kHz for the higher power application which is within the target(resonance?) frequency of LF RFID tags. So power transmission should be quite high for ...
2
votes
2answers
39 views

Reading voltage from coil on top of Qi Wireless Charger

I am a high school student doing a lab report on changing the number of turns of a coil and seeing the effect it has on the output voltage from a wireless charger. I am trying to take a Qi Wireless ...
2
votes
1answer
988 views

Wireless Power Coil - Is this shielding? Field shaping?

I'm taking apart a Qi wireless power transfer receiver. The coil is etched into the pcb. The entire coil area (approximately 3.75 x 4.5 cm) is covered by a rectangular piece of hard, brittle material. ...
2
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2answers
1k views

Inductive wireless mobile charger circuit

In wireless mobile charging circuit, is there any formula of spacing which varifies that by increasing diameter and turns, spacing (range) can be increased?
2
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2answers
142 views

Wireless chargers in series?

I'm a complete amateur at electrical stuff, although I can solder and make some basic electronics with Arduino. I'd like to wirelessly charge a battery in the rotating part of an astronomy dome. The ...
2
votes
2answers
935 views

Is the QI norm about the components or the coil?

I would like to have induction charging for my smart object and I was looking at QI chargers/receivers The QI chargers I find on the market are "designed for phones" : they are very flat and offer a ...
2
votes
1answer
78 views

Coupling coefficient variation in Wireless power transfer

Question regarding WPT compensation topologies. I'm trying to make a inductive wireless power transfer system where the RX coil can move quite conisderably relative to TX coil and still transfer ...
1
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3answers
479 views

Why is wireless power transfer done between two coils at their self-resonant frequency?

I was reading this paper about wireless power transfer via strongly coupled magnetic resonance: http://www.ijirem.org/DOC/1_Wireless%20Power%20Transfer%20via%20Strongly%20Coupled%20Magnetic7a7f01ee-...
1
vote
1answer
434 views

amplifying 555 astable multivibrator output [closed]

I am using 555 as astable multi-vibrator and its output is a square wave of 7 V and frequency is around 800 kilo hertz.But i need to increase the voltage to about 40 V . What should i do? Actually ,...
1
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2answers
113 views

Why are wireless chargers inefficient?

In the current market, the chargers are only 40-50% efficient. How much is the conversion and flux losses during transmission? Is there any way to improve the overall efficiency? Can a ferrite ...
1
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2answers
68 views

Is this quote about interference from wireless charging coils accurate?

This blog post suggests that apple dropped their promised AirPower wireless charging mat because it didn't pass EMI standards, specifically due to the (unconfirmed) idea that they were using a large ...
1
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2answers
839 views

Wireless Power transmission. Is it possible to achieve 100-200w (load side) power using off-the shelf components?

Short introduction! I've recently built electric skateboard (you can look up the commercial ones) and I want to design/get a wireless charging system for it! The problem is, it seems the current Qi ...
1
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1answer
367 views

what is the use of ultrafast diodes in wireless battery charger ckt

Instructable I am working on a wireless charger that uses a ZVS Driver circuit for the transmitting end. This is its circuit diagram: I have attached the instructable where this came from. Wireless ...
1
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2answers
695 views

Mutual inductance vs coupling coefficient

Question regarding this and this question about mutual inductance and coupling coefficient. I'm trying to analyse a two coil system: It consists of two coils like in the picture with 2 cm air gap ...
1
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2answers
425 views

Extend wireless Qi charging with a coil in the middle

I have a question regarding wireless charging. Traditionally, you have two coils, the charger and the receiver for wireless charging with Qi (from what I understand). Would you be able to have an ...
1
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2answers
80 views

Wireless power transfer through voltage spikes?

I'm sort of digging up something with this question, which relates the the whole wireless power transfer concept. I've looked at a question about power transfer and Tesla, and I know that there's ...
1
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2answers
149 views

power wireless charger from mains

I want to run a large inductor coil for wireless charging with a 12V peak, 300kHz AC signal, starting with UK Mains voltage (230Vrms 50Hz). Should I use a step-down transformer and then a frequency ...
1
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1answer
160 views

Qi charging multiple devices with single transmitter

I am looking for a Qi charging compliant transmitter and have found kits from different manufacturers like ST/TI/Microchip. These kits have one receiver and are tuned to work together. How can I ...
1
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2answers
249 views

Is a battery management system necessary for wearables? [closed]

My team and I are working on developing a wearable device (like a heart rate monitor with IP68 dust/waterproofing) and we're utilising wireless charging for our 3.7V 350mAh non-removable battery. We'...
1
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1answer
69 views

Is it possible to induce few volts IMPULS over 10 m distance?

I'm currently learning about electromagnetism at college, so this question is on mine mind for a few weeks. If we have on one side: 9 V battery, DC-DC converter to few kilovolts, capacitor, button, ...
1
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1answer
65 views

Inductive Charging 2 layer coil transfer to 1 layer receiver. Any issues?

I am looking to incorporate a inductive charging mechanism into a project I’m working on. On the receiving side I only have room for a single layer coil design. For my transfer side I have more ...
1
vote
1answer
92 views

Power IR2110 from a low voltage AC Source

I am trying to power the IR2110 using an AC Source. However, this source is also connected to a full wave bridge rectifier that's going to supply a controlled buck converter. I tried using a voltage ...
1
vote
1answer
69 views

Slayer Exciter Interfering With Voltage Measuremnet With Multimeter

I've built myself a slayer exciter and I am trying to measure the output voltage. I've created a coil with approximately 10 turns and soldered a bridge rectifier to the ends of the coil so I can ...
1
vote
1answer
92 views

How can I build my own wireless charger for my cellphone? [duplicate]

I am designing a wireless charger for my cellphone, Where my Primary coil is energised with 1.5V and 0.3A, Where I have used a transistor to turn it on and off at a frequency of 1Mhz. In the secondary ...
1
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2answers
2k views

Is it possible for a Wireless device charging pad to fry RFID / Contactless cards?

Lets say for example that a person has a wireless charger in their car centre console (an option on some new cars) This person puts their wallet and phone there and the charger kicks in. (wallet ...
1
vote
0answers
390 views

Significant voltage drop across IGBT

I'm using an IGBT in a wireless charger circuit as a swtich to send 'pulses' of power across the gap. I have 14V coming from the mosfet driver and I can see around 5v on the collector. I have the ...
0
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2answers
562 views

Does wireless charging degrade battery life? [closed]

Does a design using wireless charging such as QI effect the longevity/health of lithium-ion batteries such as those found in modern consumer electronics devices? What special considerations must be ...
0
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3answers
132 views

Inductive charging problem

I am fairly new to electronics and I recently made an inductive charger that transfers 18 volts over a couple mm from 120 volts. The problem I am having is that while the voltage transfer is good, the ...
0
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1answer
84 views

Fast charging ports under the hood - technical details behind the standards? [closed]

There are a few things I noticed and examined for two different fast charging standards: MediaTek PumpExpress works without any data communications with the charger. Output 2 from my USB multimeter ...
0
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1answer
599 views

Powering a motor through wireless electricity [closed]

simulate this circuit – Schematic created using CircuitLab simulate this circuit Schematic redrawn by Transistor. OP to edit or delete as required. I have a wireless electricity transmission ...
0
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1answer
463 views

Inductive Charging Mouse [closed]

I recently bought a wireless gaming mouse and while functionally its great, the battery life is a little less than I would like. I tried to mitigate this by adding in another rechargable AA battery (...
0
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3answers
246 views

Energy wastage in wireless charging rotary toothbrushes?

I'm not going to change my habits based on the answer, but I did wonder from a theoretical standpoint. I get idea of wireless charging. I still have flashbacks to my power generation & electric ...
0
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3answers
342 views

Wireless power transfer - Inductive vs. resonant mode

When talking about how wireless power transfer is done, the standards (e.g Qi) distinguish between inductive and resonant mode. (Link) They claim that when the units are in very close proximity it is ...
0
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1answer
91 views

Charging circuits wirelessly [closed]

After learning that some devices can be charged up wirelessly through inductive means (which https://powerbyproxi.com/wireless-charging/ illustrates), I want to try to invent a simple one myself, but ...
0
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1answer
2k views

Multiple Wireless charging coils (Qi) in parallel?

I am making a device that will be wireleslly charged and I decided to go for a standardized Qi transmitter/receiver. The device is a kind of bulk and I want it to have an option to get charged no ...
0
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2answers
175 views

Wireless energy scavenging from in-home wiring EM fields

I was wondering if it would be possible to power a little 3.3V microcontroller, by harvesting an electromagnetic field around an in-wall insulated 240V 50Hz AC power cable. Something like contactless ...