5 ms·
I talked to two of my friends who wanted to do some research into this. They told me, that in the end, power over WiFi was too inefficient, so in practicality (
by gamesbrainiac 11y ago
I talked to two of my friends who wanted to do some research into this. They told me, that in the end, power over WiFi was too inefficient, so in practicality (since they were working with phones), the technology wouldn't actually charge phones up per se, but rather make them lose charge more slowly.
- rgarrett88 11y agoYeah, I noticed the article wouldn't mention how much power they actually captured.
- Dylan16807 11y agoIs efficiency a game-stopper? I would assume the low wifi power levels are the main problem, but that can be solved by cranking up the power. And you can aim the source.
- gamesbrainiac 11y agoIt depends, when I live power is expensive, so yes efficiency or rather the lack thereof is a show-stopper.
- Dylan16807 11y agoI'm sure you'd be willing to have some amount of inefficiency, considering how low the power requirements of an idle phone are. Personally, I'd put up with a 50 watt device that only gets a watt to my phone. I'm pretty sure that's doable with a smart transmitter and small receiver.
- TeMPOraL 11y ago> considering how low the power requirements of an idle phone are Don't know about your, but my phone tends to draw ~2.4W when idle with screen on, and I'm pretty sure it stays over 1W even with screen off. That watt would, like 'gamesbrainiac said only make it lose charge more slowly. And that's just one phone. My household has 4, not counting other mobile devices like tablets and Kindles. Putting a 2% efficient (!) power system to use seems like a crazy and absolutely scary idea. Just multiply that over the number of potential users (~2 billions). Also, 98% of this energy will have to go somewhere. It probably means heat.
- Dylan16807 11y agoThe extra heat and power use is offset by my replacing incandescent bulbs with alternatives, so that's fine with me. But the only time my phone drains 1 watt with the screen off is when it's doing cellular data transfers with a terrible signal. It has an 8 watt-hour battery and it lasts more than 8 days when I toss it on a shelf to wait for calls. So if my phone's sitting there using 1/25 of a watt, a 2% efficient maintenance charge only costs 2 watts. And we can do much better than 2%.
- jacquesm 11y agoA 50 Watt device that gets 1 Watt to your phone is only 2% efficient. That 50 Watt continuous draw translates into 50 * 24 = 1200 Watt-hours daily, or 438 KWh per year. That's a lot of money to keep that one phone charged, multiplied by the number of phones in operation the power waste would be enormous. They recently banned incandescent lights here for being too inefficient, I wonder how a device like this would get a pass if all it does is replace a small piece of wire at enormous cost. And besides all that your phone draws quite a bit more than 1 Watt so it would function as a charge extender rather than a charger. And that in turn does not take into account the real efficiencies involved, I would be highly surprised if a device like the one you described had even a 2% efficiency.
- gus_massa 11y agoIf you crack up the power enought, you get an open microwave oven. (A tipical WiFi router has ~2W and a tipical microwave oven has ~800W, so there is a 400x difference.)