Tag Archive for Inductive charging

AT&T Still Trying BPL

AT&T Still Trying BPLFresh off its dismantling of net neutrality and its drunken binge of bribing its staff, AT&T (T) has launched two field trials of its AirGig technology, fueling hopes it can gain broader acceptance of its version of the failed broadband over powerline (BPL) technology. The AirGig plan, as AT&T explained in 2016, is to use millimeter-wave radio signals (above 24 GHz) to travel along power lines. Radios on the power lines would regularly refresh the signal as it travels.

At&T kogoFirecetelecom reports that the first trial was with an electricity provider outside the U.S., and the second trial is underway with Georgia Power. Stopping short of revealing a service rollout plan, AT&T will take what it learns from the trials and continue to develop AirGig. Based on its evaluation of the current trials, AT&T will look at expanding more advanced BPL technology trials in other locations. AT&T told Firecetelecom that while “there’s no timeline yet for commercial deployment, we’re encouraged and excited by what we’ve seen so far.”

The service is bullish on AirGig. The telco is touting AirGig’s potential to deliver 1 Gbps speeds via a millimeter-wave signal guided by power lines. Firecetelecom says AT&T’s Ultimate goal with AirGig is to accelerate broadband deployments.

Broadband over power line (BPL)While there have been plenty of BPL failures, AT&T claims AirGig is different. They say it is more efficient than earlier generations of BPL because it runs along, and not within, the medium voltage power lines. The technology differs from earlier BPL technologies, which traveled with the current.

In order to roll out Airgig, AT&T had to develop several new BPL innovations to distribute signals from the power lines to homes and businesses. AT&T labs developed a Radio Distributed Antenna System (RDAS), which uses low-cost plastic antennas, aka mmWave surface wave launchers, along with inductive power devices, which receive power without direct electrical connections (for simplified installation).

The RDAS will reconstruct signals from multi-gigabit mobile and fixed deployments. Those data signals are then transmitted using mmWave over power lines. The mmWave surface wave launchers are inductive power devices that create multi-gigabit signals that travel along or near the medium-voltage wire, not through it.

Maxwells EquationsThe data signal uses the existing pole infrastructures mostly line-of-sight wire paths act as a waveguide that channels the signal and improves the transmission quality, according to Mark Evans, a director on AT&T’s AirGig team. A waveguide is a structure (like an electrical wire) that restricts how much waves can expand over distance, thereby minimizing energy loss. AT&T radio technology engineer Peter Wolniansky explained in a demo that electromagnetic physics make it work,  “The signal energy clings like a glow to this wire, … It’s bound by Maxwell’s equations to stick to this wire.

Millimeter waves are radio waves from 24-300 GHz. The benefit of using these high-frequency bands is access to high bandwidth, between 100-800 MHz, which is 20-100x more than today’s common cellular systems.

AT&T plans to put wireless stations periodically along the route to provide the last-mile connections. For that last communication link to a home or business, AT&T will use more conventional wireless equipment. Customers would use 5G CPE equipment to connect to the AirGig data flow. Once the CPE has received the signal, it can use Wi-Fi (802.11ad or 802.11ac) or an LTE femtocell unit to connect to the end users’ smartphones, tablets, laptops, television, autonomous vehicles or other IoT devices. CNet quotes Mark Evans, a director on AT&T’s AirGig team.”We’re aiming to be ready to deploy it commercially in the 2021 timeframe.

CNET also quotes Gordon Mansfield, AT&T’s vice president of converged access and devices who says they are moving forward. He confirmed that AT&T has contracted with manufacturers to build more refined hardware for a new round of AirGig testing most likely in 2019.

At&T Airgig eggsA key part of the AirGig technology for AT&T is that it is easy to install. Antenna modules — AT&T calls them eggs — clamp in pairs on the power line extending each direction from the power pole. The devices can power themselves via inductive power devices without a direct electrical connection. The eggs configure themselves automatically, and the early test showed it takes people 10 minutes to hook up to the network, said AT&T Chief Technology Officer Andre Fuetsch.

rb-

Kudos to AT&T for trying to figure out how to get everybody else to do their work just like Tom Sawyer..

AT&T can use the existing electrical right of way to bypass local municipality requirements, a long-running tactic of AT&T.

AT&T does not want to be in the business of connecting customers. They want to use the electric company’s infrastructure for free because fiber optic cable is expensive to bury underground or string along telephone poles.

AT&T will be using totally free unlicensed spectrum to sell access back to us at a huge profit.

They don’t even want to pay for electricity to run the equipment. They are using inductive power right off the mainline so it is not metered, which means everybody will have to pay.

 

Related article

 

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedInFacebook, and Twitter. Email the Bach Seat here.

Is Your Battery Healthy?

Li-ion batteries need very different care and feedingLithium-ion batteries have been in the news lately for causing fires and explosions. Explosions have happened with e-cigarettes, hoverboards, and the Samsung Galaxy Note 7, which was banned from all flights by the FAA due to its explosion risk. Despite the risks, most of today’s most popular gadgets have a battery.

Is Your Battery Healthy?Fred Langa at Windows Secrets Newsletter posted an article on how to get the most out of the lithium-ion (Li-ion) batteries. Li-ion batteries need very different care and feeding than the nickel-cadmium (Ni-Cd) and nickel-metal-hydride (Ni-MH) batteries used in earlier devices. Proper care of a Li-ion battery can result in as much as 15 times longer service life than with an improperly cared-for battery.

Steps to extend the battery service life

The article does not cover ways to get more run time between recharges; those techniques are already well-known. Most portable devices offer ample manual and automatic power-saving modes and methods such as adjusting screen brightness, slowing CPU speed, and reducing the number of apps running.

15 times longer service lifeRather, the article focused on ways to extend the battery’s overall service life. Follow these five important tips, and you’ll help make sure that your Li-ion batteries will deliver long, full, safe service lives in your new portable devices.

Keep your lithium batteries cool

Heat is the number-one enemy of Li-ion batteries. Heat issues can be caused by usage factors such as the speed and duration of battery charging and discharging. The physical environment also matters. Simply leaving your Li-ion powered device in the sun or in an enclosed car, even if the device isn’t being used, can significantly reduce the battery’s ability to take and hold a charge according to the article.

battery capacity can be reduced by 50%.Li-ion batteries perform best at about normal room temperature (68F/20C). If the device warms to 86F/30C, its ability to hold a charge drops by about 20%. Mr. Langa says if the battery is used at 113F/45C — a temperature easily reached by devices that are working hard or that are in the sun, battery capacity can be reduced by 50%.

So if your device or battery becomes noticeably warm while you’re using it, the article recommends moving to a cooler place. If that’s not possible, try reducing the amount of power the device is using by turning off unneeded apps, reducing screen brightness, or activating the device’s power-saving mode.

Of course, you can turn the device fully off until its temperature returns to normal. For fastest cooling, remove the battery, if possible Windows Secrets recommends. The battery and the device will cool off faster if they’re physically separated according to the article.

Low temperatures aren’t as much of a worry. Low temps usually won’t cause any long-term damage, although a cold battery won’t produce as much power as it otherwise would. The power drop becomes very noticeable at temperatures lower than about 40F/4C. Most consumer-grade Li-ion batteries are essentially useless at temperatures below freezing.

If your Li-ion powered device becomes excessively chilled for any reason, don’t try to use it. The article says to leave it powered off and move it to a warm place until the device is at normal temperature. Once the battery warms to a normal temperature, so will its electrical performance.

Unplug the charger

Overcharging, leaving a battery connected to a too-Unplug the chargerhigh voltage source for too long, can reduce a Li-ion battery’s ability to hold a charge, shorten its life, or kill it outright according to the author. Most consumer-grade Li-ion batteries are designed to work at around 3.6 volts per cell but will accept a temporary overvoltage of around 4.2 volts while charging. Mr. Langa warns that if a charger outputs the higher voltage for too long, internal battery damage can occur.

In severe cases, Windows Secrets warns that overcharging can lead to what battery engineers delicately refer to as “catastrophic failure.” Even in moderate instances, the excess heat produced by overcharging will negatively affect battery life, as you saw in Tip #1.

High-quality chargers can work in concert with circuitry inside well-designed Li-ion-powered devices and their batteries, reducing the danger of overcharging by properly tapering off the charging current. The article says the simplest, can’t fail method is not to leave your Li-ion devices connected to any charger longer than needed.

These properties are quite different from those of older Ni-Cd and Ni-MH battery technologies, which did best when left on their chargers for as long as possible. That’s because those older battery types have a high rate of self-discharge; that is, they start losing a significant amount of stored energy the moment you take them off the charger, even if the device they power is turned off.

In fact, a Ni-Cd battery can self-discharge at a rate of 10% in the first 24 hours. The self-discharge curve flattens after that, but a Ni-Cd battery will still lose an additional 10–20% charge per month. Ni-MH batteries are even worse. Their self-discharge rate is about 30% higher than that of Ni-Cd.

But Li-ion batteries have a very low rate of self-discharge. A healthy, full, lithium battery will self-discharge at about only 5% in the first 24 hours off the charger — with only 2% or so per month after that.

It’s simply not necessary to leave a Li-ion device on the charger until the last possible moment. For best results and the longest battery life, unplug the charger when it or the lithium-powered device shows a full charge.

It’s also not necessary to give new Li-ion devices an extended charge before first use. (Ni-Cd or Ni-MH devices used to come with warnings to do an initial charge of anywhere from 8 to 24 hours.) Li-ion batteries are fully ready for use when the charger or the device reads 100% charge. No extended charging is needed.

Don’t deep-discharge your battery

Not all discharge cycles exact the same toll on a battery. Long and heavy usage generates more heat, putting more stress on the battery; smaller, more frequent discharges extend the overall life of lithium batteries.

Don't deep-discharge your batteryYou might think that a higher number of small discharge/recharge cycles would eat into the battery’s overall lifespan. That was true with older technologies, the author says it’s not the case with Li-ion. Battery specs can be confusing because most manufacturers count a full Li-ion charge cycle as whatever it takes to add up to a 100% charge. For example, three 33% discharge/recharge cycles equal one full-charge cycle, five 20% cycles equal a full charge, and so on.

In short, a higher number of small discharge/recharge cycles doesn’t reduce a lithium battery’s total available full-charge cycles.

Again, heat and stress from heavy discharges cut battery life. So try to keep your deep-discharge events to a minimum. Mr. Langa recommends that you don’t let your device routinely run down to zero charge (where the device turns itself off). Instead, think of the bottom 15–20% of battery capacity as a reserve — for emergency use only. Get into the habit of swapping in a fresh battery (if possible) or plugging the device into external power well before the battery is empty.

Slow and steady is best

Slow and steady charge/discharge is bestAs you now know, both fast discharging and fast recharging generate excess heat and exact a toll on battery life. Windows Secrets says if you’ve run a device long and hard, let the battery cool to room temperature before recharging it. Batteries won’t accept a full charge when hot. And when recharging, make sure your charger doesn’t make the battery become hot to the touch, a hot battery is a sign the charger is pumping too much current, too fast, through the battery.

Overcharging is more likely with chargers that are cheap, off-brand models; that use fast-charge circuitry; or that are wireless (inductive). These “dumb” chargers simply pump out current, accepting little or no feedback from the device being charged. Overheating and overvoltages can easily occur, damaging or even destroying the battery.

Fast chargers provide a useful charge to a drained battery in minutes and not hours. The author explains there are various approaches to fast-charging technology, and not all of them are compatible with all lithium batteries. Unless the charger and the lithium battery are specifically designed to work together, fast charging could cause overheating and overvoltages. Generally, it’s best not to use one brand of fast charger on a different brand’s device.

Wireless (inductive) chargers use a special charging mat or surface to restore a battery’s power. It sounds wonderfully convenient, but inductive charging always generates excess heat, even when it’s working normally.

Not only is the excessive heat produced by a wireless charger not good for lithium batteries, it also wastes energy. By its nature, inductive charging’s efficiency is always going to be lower than a standard charger’s. Mr. Lunga says that higher heat and less efficiency easily outweigh convenience.

In any case, the safest approach is to use only chargers sold by the OEM of your lithium-powered device. It’s the only way to be sure that the charger will keep temperatures and voltages within specs. The article recommends that if a OEM charger isn’t available, use a low-output charger that’s unlikely to pump damaging amounts of power into the device you’re charging.

One source of low-output, non-OEM charging that’s often available is the USB port on a standard PC. A typical USB 2.0 port provides 500mA (.5 amps) per port; USB 3.0 provides up to 900mA (.9 amps) per port. In contrast, some dedicated chargers will output 3,000-4,000mA (3-4 amps). The low amperage offered by USB ports will usually provide cool, safe charging of almost any Li-ion device.

If possible, carry a spare battery

carry a spare batteryIf your device allows for easy battery replacement, carrying a spare battery is cheap insurance. It will give you twice the run time. When the in-use battery approaches 15–20% charge, simply swap out the drained battery for a fresh, cool one — you get instant full power, with no heat worries.

A spare battery also allows for other benefits. For example, if you find yourself in a situation where the installed battery is running hot, you can swap out the hot battery to let it cool. Having two batteries should also eliminate any need to use fast chargers — you can charge the spare at a safe, slow rate while the other is in use.

rb-

For more tips on how to keep your Apple iPhone battery in tip-top shape, check out this post from 2014.

Related articles

 

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedInFacebook, and Twitter. Email the Bach Seat here.

Wireless Charging for iPhone

Wireless Charging for iPhoneApple Computers (AAPL) has fired an opening shot in the wireless charging patent warfare. Patently Apple reports that the now Jobs-less firm has filed for patent protection on inductive wireless charging for iPhone, iPod, and iPad. The patent “Using an Audio Cable as an Inductive Charging Coil,” is available at the U.S. Patent Office website.

TApple logohe patent application in typical Apple style, calls for a “wireless” charging solution that uses wires. Apple wants to use headphone wires rather than supplying a power cable. The wired wireless charging system includes a tower that would sit atop your desk. According to MIT’s Technology Review, to charge an iPhone, specially designed earphones must be wrapped around the tower multiple times. Finally, the earbuds are to be placed on the device, where special conductive metal mesh would begin funneling electricity to your device.

Apple Inductive Charging Patent

TR says the charging tower is an eyesore, wrapping earphones around it would be a hassle and the whole thing is decidedly un-Apple-like in its unwieldy and cumbersome nature. Other opinions are “Incredibly impractical,” “ridiculous,” “like an iPhone scratching post,” “Tolkien-esque.”

WiTricity logoTR and Gizmodo believe this patent application is a “red herring” and Apple has other things in mind. Back in May 2011, MacRumors noted Apple’s interest in WiTricity, As MacRumors pointed out an international patent application filed by Apple which cites the original MIT paper as the foundation of WiTricity’s business plan.

rb-

I have already covered wireless electricity a couple of times. The obelisk charging patent is so out of character for Apple design that I believe it is a head-fake. With their closed eco-system, Apple can create a closed version of the WiTricity technology and charge a premium for it.

 

Related articles

 

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedInFacebook, and Twitter. Email the Bach Seat here.

Wireless Electricity for Car Charging Coming

Wireless Electricity for Car Charging ComingThomas Lee at Xconomy reports that Delphi and WiTricity of Watertown, MA demo’d a wireless  electricity charging system for cars at the Society of Automotive Engineers (SAE) annual World conference in Detroit. The demo was the result of a seven-month partnership between the firms to use WiTricity’s technology to wirelessly transmit electricity via magnetic waves to charge electric cars.

Delphi logoThe charging system developed by Delphi and WiTricity would enable cars powered with electricity to reboot without having to plug into a power source via a cord according to Xconomy. It would only need cars to park over a wireless electrcity source on the floor of a garage or embedded in a paved parking spot, which would then transfer the power to the vehicle’s battery charger.

WiTricity, founded by MIT physics professor Marin Soljacic in 2007, has designed a transmission coil that connects to a small electronics module and converts the traditional electric current found in a home or office to a higher frequency and voltage, to create an oscillating magnetic field around the coil. The article says if a separate coil designed to resonate to the same frequency is close enough to the source, power is transferred between the two coils.

The article quotes Mr. Sumner who says the prototype generates about 95 percent efficiency, meaning only five percent of the power being generated gets lost in transmission. Delphi hopes all cars equipped with the technology will get at least 90 percent. The pad powering the Chevy prototype was transmitting about 2.6 kW, or 16 amps, of electricity, about the equivalent of Delphi’s current Level 2 wired chargers.

Randy Sumner Delphi’s director of global hybrid vehicle business development says WiTricity’s technology enabled Delphi to design much smaller coils and achieve greater distance between the bottom of the car and the charging pad. In theory, this could allow bigger trucks and vehicles to also use the technology. In an interview, Andrew Brown, Delphi’s executive director, and chief technologist says wireless charging will go a long way to boosting the popularity of electric cars. Wireless charging pads could be installed in home garages, parking lots, offices, shopping centers, he says.

“It will eliminate this range anxiety,” says Mr. Brown, referring to consumers who worry they will run out of juice before finding the next charging station. Also, he says, “The average consumer is not accustomed to electric cars. [They worry] ‘Am I going to get dirty?’ or “Will I get electrocuted?’” Wireless charging helps with both those issues. All consumers have to do is “park and charge,” Mr. Sumner says in the article.

The author notes that Delphi still faces a long road from lab prototype to mass production. The company needs to work with OEMs to figure out how to best integrate WiTricity’s technology into cars. Delphi envisions a car that can be charged both by wired and wireless charging stations. The company also needs to find ways to shrink the electronics and reduce overall cost. Delphi officials estimate the first cars using it will roll off the assembly lines in 2014 or 2015. “This is real,” Mr. Sumner says. “This works.”

rb-

The idea of wireless electricity is not new. I have followed wireless electricity since 2008, here and here. Look Ma! No wires!

What do you think?

Can a car be wirelessly charged like an iPod?

 

Related article

 

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedInFacebook, and Twitter. Email the Bach Seat here.