Airnergy WiFi power system gives RCA a reason to exist (video)

We don't usually associate RCA with new and innovative technologies, but we think know they're on to something with its Airnergy power system, which harvests energy from WiFi signals. Shipping this summer, the pocketable dongle picks up WiFi signals from the air and manages to charge an internal battery through some magic inside. You don't have to connect to a network, you just have to be in a place that has signal, and it will automatically charge up. As if we weren't intrigued already, they told us that they're planning on building the tech into actual cellphone batteries, so you would theoretically never need to plug in again and your device would always be topped off. Yeah, we want.

Airnergy WiFi power system hands-on

[jamiedyerhotmailcom Posted Jan 11th 2010 3:07PM]

Sorry to rain on your parade...

Unfortunately this thing is just snake oil and a bit of marketing hype. I work as an electronic engineer and my jaw awmost hit the floor when I realised the audacity of RCA.

Firstly some numbers. The average wired charger provides somewhere in the region of 2 - 3W of power when charging a mobile. The average wifi router emits less than 100mW which means that even if one of these devices captured 100% of the energy coming from a single router, it would take 20 - 30x longer to charge than normal. Fair enough. Still usable (although nobody else would be able to use the wifi signal ;o).

Here's the upsetting part. Even if you placed the device right next to a router it would collect hardly any of the signal power and would be MUCH less than 100% efficient. And then to compound this, as soon as you move away from the source, the power collection drops significantly.

If I had to take a stab I would guess that it could collect in the region of 1mW power EVEN with multiple wifi sources and other background radiation. This means it would take roughly 100 days to collect enough energy to charge a mobile phone once... Saving you less than $0.01 (but wait, didn't you already pay $39 for the thing in the first place?).

My guess it that for the show they manually fully charged the internal battery of the device.

I would also suspect that they will give customers the opportunity to manually charge the device via USB effectively turning it into a spare battery and masking the fact that it hardly recoups any of the wasted energy from wifi routers.

I am all for sustainability but I suspect that this device would use more energy to make than it would recoup in a lifetime of use... and you certainly wouldn't make your $39 back. Still, if all you want is a spare battery, don't let me stop you!

[jamiedyerhotmailcom Posted Jan 11th 2010 4:30PM]

UPDATE: I just found an article about a similar Nokia device:

Nokia have a prototype device that harvests 3 - 5mW in optimal conditions, which means that my estimate of 1mW is probably correct for the average urban area.

It would save you about $0.01 cent / year.

In order to recoup the manufacturing energy / transportation energy etc. involved in getting the device to you, it would take over 100 years of constant use. That doesn't include recouping the energy wasted by employing the RCA marketing department

[jamiedyerhotmailcom Posted Jan 11th 2010 3:15PM]

...oh and shame on endgadget for giving the airnergy credibility.

[wickedwobotics Posted Jan 12th 2010 11:34PM]

This things produces 9 watts! lol
http://www.futurehorizons.net/free.htm