Self-Charging Phones Are On The Way

Megalith

Megalith

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Sure, wireless charging is neat, but what if your smartphone could recharge without a power outlet?

The case that Will Zell slides onto his iPhone doesn't look that unusual, but it's doing something pretty out of the ordinary: capturing some of the radio waves that the phone transmits when connecting to cell-phone towers and Wi-Fi routers, converting them to electricity, and feeding that power back to the phone's battery.
 
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You're kidding, right? In order for this to be effective you need a free supply of radiant energy. Which doesn't exist.

In addition, absorbing RF energy means that it will no longer go to maintaining a cell / bluetooth signal.

Finally the device claims to "recover up to 30% of the battery power from RF", which is pretty impressive ... if the phone's TX were using 30+% of the battery power, which it's not (think: screen, processor, RAM refresh, etc.).

People who fall for this scam are the same ones who think you can perpetually charge a flashlight by shining the light into a solar cell.
 
rpeters1969 said:
You're kidding, right? In order for this to be effective you need a free supply of radiant energy. Which doesn't exist.

In addition, absorbing RF energy means that it will no longer go to maintaining a cell / bluetooth signal.

Finally the device claims to "recover up to 30% of the battery power from RF", which is pretty impressive ... if the phone's TX were using 30+% of the battery power, which it's not (think: screen, processor, RAM refresh, etc.).

People who fall for this scam are the same ones who think you can perpetually charge a flashlight by shining the light into a solar cell.
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No kidding.

The amount of energy that is to be found in radio waves that make it to the phone will be so small once you think about how diffused it is at the single small point, and if you are trying to recover energy from what is coming from the phone you are going to be blocking ALLOT of your signal which already went through an energy loss to make, then it is going to be converted back to energy with another loss....Why not just turn down the transmitter power and save more juice than you will ever recover back. Signal, as stated above is such a small portion of the power, look at low end windows or flip phones that will stay on for days at a time on smaller batteries, its all about high end screens and lots of CPU/GPU power that is killing the battery, signal is the last place to start.
 
In theory it sounds plausible, I mean if you could harvest ALL of the different types of RF waves floating around (wifi, 4g, 3g, etc) that weren't being used by your phone, that would be awesome. But the counter side to this awesomeness would have to be a system that effectively kills your phone's ability to receive said signals. How much potential storable energy do these types of RF carry anyways? I wouldn't imagine it would be much, but if you lived in a big city where there are millions of wifi signals being broadcasted maybe you could harness something.

I wish I understood the science behind it, but from an outsiders perspective, if MIT is writing about it it can't be all fairy tales.
 
As mentioned above, collecting the cellphone energy is a dumb idea. Cellphone manufacturers can make hardware that reduces cell RF radiation to lower power draw, but I believe that such measurements are already being used to some extent. Not to mention your proximity to a cell tower correlates to how much power your pone needs to stay connected.

If you want to collect RF energy, collect broadcast radio energy. A radio tower can generate 5,000-100,000 watts of RF energy. Obviously that much power won't be present right where you are standing, but it would likely be more than whatever your cellphone generates.

I worked on an AM radio mast in Yankton, SD once. We were there to repair the ground straps that radiate out from the tower that forms the ground for the AM radio tower so that it can transmit RF energy. AM radio towers are live, as in, you will get electrocuted if you are grounded and you touch the tower. This station had a couple of smaller backup towers that the radio engineer switched the broadcast to. The main tower is 900' tall and it can collect so much RF energy from the other backup towers that jumper cables have to be used to ground out the tower to make it safe to work on. When connecting the jumper cables there is a loud crack and a noticeable arc.
 
rpeters1969 said:
You're kidding, right? In order for this to be effective you need a free supply of radiant energy. Which doesn't exist.

In addition, absorbing RF energy means that it will no longer go to maintaining a cell / bluetooth signal.

Finally the device claims to "recover up to 30% of the battery power from RF", which is pretty impressive ... if the phone's TX were using 30+% of the battery power, which it's not (think: screen, processor, RAM refresh, etc.).

People who fall for this scam are the same ones who think you can perpetually charge a flashlight by shining the light into a solar cell.
Click to expand...

Not perpetually charge, think regenerative braking, recovering some of the energy to increase efficiency.

However, greater efficiency gains with CPU and screen will yield better results I think.
 
I'm pretty sure this was debunked .. Hackaday maybe? One of the sites did a pretty scientific explanation why this won't work worth a damn.
 
Buncha noobs. I've been fast-charging my phone in the microwave for years.
 
Spidey329 said:
I'm pretty sure this was debunked .. Hackaday maybe? One of the sites did a pretty scientific explanation why this won't work worth a damn.
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Here's one: http://hackaday.com/2015/05/05/techcrunch-disrupt-charging-a-phone-with-its-own-transmitter/

One nice thing about Hackaday is there are a lot of smart people who read it (mixed with the internet "wiki-geniuses" of course), so the comments can yield some good results - the smart ones usually post sources/references.
 
Though Zell acknowledges that there’s plenty of skepticism surrounding the utility of harvesting energy from radio waves, he says Nikola Labs’ technology works because it’s doing the harvesting so close to the transmitting antenna in the phone, and that it’s capturing radio waves that aren’t needed for communication in order to avoid impacting call quality.
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This sounds a lot like perpetual motion to me. Using capturing the cell phones transmission power, then using that (after some efficiency loss) to power the cell phones transmission.

Now granted I don't know too much about cell phones, and perhaps when you make a phone call it transmits in WiFi, 3g, 4g, and all those other things whether or not it needs to, but seems to me a better option would be to simply turn off that transmission in the first place and save even more power.
 
There are some ultra low power sensors that use radio to power them, but even using ultra wide band with pretty good sized antenna (far larger than what you find in a phone), they were able to get 15µW out of it, which is to low even for these purpose built sensors, they have to use a charging system and once the system reached the needed power they turn on, take a reading and turn off. 15µW is nothing to a cell phone, the size of the case and items inside could just be used to make the battery bigger from the start and gain a million fold the power you would get back from this thing.
 
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