Wireless charging

Thread Starter

kimdenton

Joined Feb 1, 2024
3
Hi, I am currently doing a project making a panel with some RGB LED strip on it which should be movable. Due to some size constraints, I have moved away from using a LiPo battery to power it and I am wondering how practical it would be to have the panel run solely through wireless charging? The LEDs are using quite a lot of power so I am concerned that the wireless charger wouldn't give enough power to run the LEDs. I don't have a huge amount of electronics knowledge so any advice would be greatly appreciated!
 

BobTPH

Joined Jun 5, 2013
9,124
Is there a reason you cannot power it from an AC adaptor? What would the wireless charger be powered by? Over what distance do you expect the the wireless charger to work?
 

Alec_t

Joined Sep 17, 2013
14,370
Due to some size constraints, I have moved away from using a LiPo battery to power it and I am wondering how practical it would be to have the panel run solely through wireless charging?
To handle any significant power the wireless charging system would almost certainly occupy a lot more space than the LiPo battery.
 

nsaspook

Joined Aug 27, 2009
13,418
Based on the this:

I think he thinks the wireless charger can be far away. That is why I asked about the distance.
Yes, wireless charging doesn't mean remote charging in the vast majority of practical cases.

Every transformer is a wireless energy transfer device.
 

MisterBill2

Joined Jan 23, 2018
18,934
Wireless charging can even be high powered. I have read articles touting the benefits of wireless charging for electric vehicles. They claim 95% efficiency. That leaves 5% as wasted, and 5% of ten kilowatts is 500 watts either turned into heat or radiated as magnetic energy.
Certainly very close proximity can improve efficiency, but the whole claimed benefit of wireless is not requiring such close proximity.

So for the LED project I suggest a wired connection of adequate length, AND, most important, the correct kind of wire. The kind of wire used will either make or break the rest of the project. And in many localities there is no source of the best choice wire at any price, much less at a reasonable price.
 
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nsaspook

Joined Aug 27, 2009
13,418
The problem with wireless charging is pretty fundamental. It's mainly a user nicety "convenience factor" , not a engineering show-stopper requirement for the vast majority of uses.
If you can drive, you can plug in an EV, just like if you can drive, you can pump your own gas (even in Oregon now).
 

MisterBill2

Joined Jan 23, 2018
18,934
Actually, Nikoli Tesla DID create a sample of wireless power transmission at a distance. And we are all very fortunate that it never became practical. Consider what the effects of such an intense electrical power field would have on almost everything.
Fortunately some very bad ideas wind up also being impractical.
 

nsaspook

Joined Aug 27, 2009
13,418
Actually, Nikoli Tesla DID create a sample of wireless power transmission at a distance. And we are all very fortunate that it never became practical. Consider what the effects of such an intense electrical power field would have on almost everything.
Fortunately some very bad ideas wind up also being impractical.
Yes, the original Tesla coil was a resonant wireless system (near field induction using spark-gaps, not far field EM radiation) that could very imperfectly transfer power and it made pretty sparks. Not much has really changed in that technology since then other than better, more efficient drivers for resonators but the physics of power transfer using this mode remains the same, quickly decreasing efficiency with coil separation and more expense/complexity VS a wired connection.
 
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MisterBill2

Joined Jan 23, 2018
18,934
Actually, it would be possible to power the LED assembly at a distance of several feet.
Start with the the transformer, rectifier, capacitor, and magnetron from a higher powered microwave oven. Mount the magnetro on a directional horn antenna system. Use a similar antenna receiving antenna with a suitable diode to rectify the RF back into DC voltage. A switcher supply can then deliber the correct voltage to the LEDs .
Of course it will be required to stay out of the path of the microwave energy to avoid being cooked. That is the compromise with higher powered wireless energy transfer.
 

WBahn

Joined Mar 31, 2012
30,236
They're playing some gamesmanship with their claims. They are careful to slip in, one time and in passing, that the 82.5% efficiency is based on the power that fell onto the antenna. They never mention how much power was actually transmitted, only that the transmitter was capable of transmitting 500 kW. So how much power was actually transmitted (i.e., how much power did NOT fall on the antenna)?

I tracked down the JPL report and only 11.3% of the klystron output power was incident on the receiving array (despite using a very high gain antenna at a rather short distance). So that 82.5% efficiency number sinks to less than 10%. This doesn't consider the efficiency of whatever would be converting the energy from it's original source to a form suitable for transmission in the first place. Furthermore, in the test that ran 65 hours, about 0.3% of the receive array diodes failed. May not sound like much, but if that rate were representative, about 1/3 of the diodes would fail each year (but there's almost certainly a bathtub mortality effect at play and engineering would almost certainly be able to reduce the failure rate to an acceptable level).

Oh, and in case that notch in the top of the antenna where a panel is missing caught your attention, that wasn't intentional -- they simply ran out of money to complete the array.
 

MisterBill2

Joined Jan 23, 2018
18,934
My other point was about avoiding the beam to avoid being cooked. On an un-named U.S. Navy ship there are reports of seagulls being cooked flying thru the radar beam. It seems that while the beam is lethal it fails to cook adequately enough for human consumption. So there are "additional considerations" relative to wireless power transmission.
Those folks who are already paniced about "EMF" hazards will totally freak-out.
(I was recently given a catalog/propaganda book published by the "LessEMF" company. It includes warnings about the radiation hazards of Smart Meters and 5G technology. )
It would be funny if it were not such a collection of lies and vastly expensive shielding clothing.
The claims that "electromagnetic fields are harming us are difficult to read without developing serious contempt for such liars.
 

nsaspook

Joined Aug 27, 2009
13,418
They're playing some gamesmanship with their claims. They are careful to slip in, one time and in passing, that the 82.5% efficiency is based on the power that fell onto the antenna. They never mention how much power was actually transmitted, only that the transmitter was capable of transmitting 500 kW. So how much power was actually transmitted (i.e., how much power did NOT fall on the antenna)?

I tracked down the JPL report and only 11.3% of the klystron output power was incident on the receiving array (despite using a very high gain antenna at a rather short distance). So that 82.5% efficiency number sinks to less than 10%. This doesn't consider the efficiency of whatever would be converting the energy from it's original source to a form suitable for transmission in the first place. Furthermore, in the test that ran 65 hours, about 0.3% of the receive array diodes failed. May not sound like much, but if that rate were representative, about 1/3 of the diodes would fail each year (but there's almost certainly a bathtub mortality effect at play and engineering would almost certainly be able to reduce the failure rate to an acceptable level).

Oh, and in case that notch in the top of the antenna where a panel is missing caught your attention, that wasn't intentional -- they simply ran out of money to complete the array.
Yes, gamesmanship is a nice word for their claims. I posted that to show both that we're already tested higher powered microwave and to show like you've said, don't believe bogus claims of magical efficiency with modern technology as claims have been exaggerated for decades.
 

nsaspook

Joined Aug 27, 2009
13,418
My other point was about avoiding the beam to avoid being cooked. On an un-named U.S. Navy ship there are reports of seagulls being cooked flying thru the radar beam. It seems that while the beam is lethal it fails to cook adequately enough for human consumption.
1714572756014.png

BS (the un-named U.S. Navy ship is called the USS NEVERSAIL) for radar in normal operations. The exposure times would be far too short.
https://zoryglaser.com/wp-content/u...CROWAVES-ON-BIRDS-PRELIMINARY-EXPERIMENTS.pdf

What they likely saw was spy-bird countermeasures. ;)
https://www.bbc.com/news/world-us-canada-49692534
The CIA has declassified details of its secret Cold War spy-pigeon missions.

The files reveal how pigeons were trained for clandestine missions photographing sensitive sites inside the Soviet Union.

The release also reveals how ravens were used to drop bugging devices on window sills and dolphins were trained for underwater missions.

The CIA believed animals could fulfil "unique" tasks for the agency's clandestine operations.
We had them and the Soviets had them. Never trust a Russian Seagull.
1714571870778.png
 
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MisterBill2

Joined Jan 23, 2018
18,934
What stopped the one discussion was the comment that at a 10 KW charging rate and 99% effective power transfer, that left 100 watts drifting into space. I pointed out that with only 100 watts, HAM RADIO OPERATORS CAN TALK ALL OVER THE WORLD. That is well documented many times over. So much for the leaked power not going any where.
 
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