Monday, December 3, 2018

How Power Consumption Impacts User Experience

Battery capacity is finite. As a result, the average power consumption determines how often the user has to replace batteries. Since manufacturers want battery replacement to be as infrequent as possible, they seek to lower power consumption. Lowering power consumption limits the functionality that a device could have.

Let’s run some numbers:

A high-end AA alkaline battery provides 2500 mAh under optimal load. This translates to 3.75 WH for a single battery. If a device has 8 AA batteries – which is probably the higher end of what’s acceptable – the total power available for the device is 30 WH.

If you assume the customer is not using a high-end battery or using a rechargeable battery, that total available capacity is lower. If you are interested in more detail, has lots of data on various types of batteries.

If you are willing to use two D batteries, the total available power is about 40 WH. Using two D batteries would, of course, make the device larger and heavier.

Let’s analyze how much operating time 30 WH would give you for various average power consumption.

Average consumption (mWH)Expected operating time
1         1,250           41.7             3.5
2            625           20.8             1.7
3            417   13.9     1.2
5            250       8.3          0.7
10       125          4.2          0.3
20   63          2.1          0.2
50            25          0.8          0.1

You can see that even under optimal load conditions, and even when using 8 high-end AA batteries, the time between battery replacements becomes shorter than 6 months when the average power consumption is about 6 or 7 mW.

Of course not all devices will want 8 AA batteries. An Arlo Pro video camera, for instance, accepts four CR123A battery. This Lithium battery has the capacity of 4.5 WH at most, so a total of about 18 WH. High power consumption is related to video streaming. Making some assumptions about power consumption of the camera:
  • If the camera averages 10 seconds/day of video streaming, the battery would last for 4 months.
  • With an average of 6 minutes/day of video streaming, the battery would last about 2 weeks
  • With an average of 1 hour/day of video streaming, the battery would last about 1 day.
Would you be happy replacing 4 CR123A batteries in a camera every 2 weeks? I know I wouldn’t be!

Thus, power consumption determines the frequency of battery replacements, which in turn impacts user experience.

But what if a vendor wants to create a device with an average power consumption of 10 mW, or 50mW or 100mW?

In that case, manufactures have to use a power cord. But a power cord negatively impacts the user experience in a different way: need to be close to a power outlet, more difficult to move the device, sometimes need to hide the power cord.

This is where long-range wireless power comes in. The ability to deliver 300 mW or even 3 Watts at a distance can revolutionize power delivery and the user experience. With wireless power, you can get the convenience of wire-free devices but add features and usability that is similar to wired devices.

Thursday, November 29, 2018

Does your bathroom have enough electrical outlets?

Mine does not.

I have two outlets near my bathroom counter and there seems to be a “competition” on what to plug in:
  • Toothbrush
  • Electric shaver
  • Water pick
  • … and that’s before whatever hair care or other products that my wife wants to plug in.

The result? a cable mess; devices that are need to be re-plugged before they are used; batteries that don’t charge.

Is it a critical problem to solve in my household? Probably not. But it would sure be convenient and neat if there was a way to keep these devices charged without plugging them in.

Now, If there was only an IR-based wireless charging solution that would safely deliver power to many devices…

Friday, November 23, 2018

The two key technologies driving smart home innovation

By now, you think you’ve seen everything: smart speakers, smart refrigerators, biometric door locks, even smart beds. But in reality, another wave of smart home innovation is coming. If the previous one was driven by AI and broadband, what are going to be the drivers of the next wave of innovation?

AI. Exemplified by intelligent assistants like Amazon Alexa or Apple Siri, it’s easy to expect that additional devices would embed intelligence, and that intelligent devices would become even smarter. Devices that anticipate your needs. Device that smartly analyze the environment. Devices that optimize energy consumption. Ordinary devices (wall clocks? bathroom mirrors?) that add useful information. Interconnected devices that learn and adapt to your preferences.

Wireless power. For years, product designers had to choose between battery operation and power cords. Batteries offered freedom of placement, but placed severe restrictions on available power. Power cords delivered all the power you want, but forced devices to be close to power outlets. But what if technology allowed you to be wire-free, yet offered 100x even 1000x the power budget of batteries? That technology is long-range wireless power.

All of a sudden, the choice between power and freedom because a false choice: you can have both. Devices that were previously battery operated can have much more functionality – such as AI capabilities – without requiring frequent battery replacements. Wired devices are suddenly afforded the freedom of installation and placement. Imagine smart speakers that you could mount or place anywhere. The sky is the limit when power cords are not tethering you to earth.

This new wave of smart home devices will be exciting. AI and wireless power are the key enablers of this new wave.

Friday, November 9, 2018

Powering today's phones with tomorrow's charging technology

One day, most phones will include an embedded Wi-Charge wireless power receiver. When that day comes, users will be free. Free from managing battery levels, from power cords, charging pads and power banks.

What can Wi-Charge do to help until that day? What can we do to pair tomorrow’s charging technology with today’s phones?

Our new AnyTable offering does exactly that. It combines a magnetic induction (“Qi”) pad with the Wi-Charge power receiver to create wire-free charging stations. It allows many existing phones to enjoy the freedom gained by wire-free charging.

Here’s how they work. Newer phones from al major manufacturers include support for charging pads. AnyTable has a standard charging pad, but unlike other pads that need a power outlet, our pad connects to a rechargeable battery. The Wi-Charge power receiver delivers wire-free power to this battery.

Why is it good to deliver wire-free power to the battery? Because it allows the AnyTable charging station to be far away from a power outlet.

For example, let’s assume that you run a coffee shop and you want to offer phone charging to your customers. Today, customers look for open outlets and use those to charge their phones. They need to remember to bring their power cords. They choose the table based on its proximity to an available power outlet. Customers wait for outlets to open. They might even leave if they can’t find one.

Some owners installed Qi pads to make it simpler for customers. But these pads still need to be close to an outlet, so they are not available on all the tables. With AnyTable, you can place a charging station anywhere you want. Away from a wall. In a busy waiting area. In a hotel lobby. All you need is to install a Wi-Charge power transmitter to deliver that energy.

Summarizing the benefits:
  • Users get a charging solution that works on any table.
  • The solution is compatible with phones from all major manufacturers.
  • Charging as is fast as a wired pad. The battery delivers as much energy as required.
  • The Wi-Charge receiver replenishes the battery

In short, AnyTable uses tomorrow’s charging technology to charge today’s phone.

Sunday, October 28, 2018


Wikipedia defines Simpexity as “an emerging theory that proposes a possible complementary relationship between complexity and simplicity. The term draws from General Systems Theory, Dialectics (philosophy) and Design.”

I think about it as “Simple on the outside, complex on the inside”. For instance, a Google search. On the outside, it’s a simple Web page. Behind the scenes, the complexity is almost unimaginable.

To me, that’s one of the beautiful things about the Wi-Charge long-range wireless power solution. On the outside, integrating is extremely easy. Embed the receiver in your product. Your product will receive power from the receiver’s USB connector (or just a +5V and GND wire, if you prefer). You have an optional data link if you want to use it – but you don’t have to. That’s it. No antennas. No complex circuitry. Just a simple 5V interface.

On the inside, it’s quite sophisticated. Just consider that a thin and focused IR beam searches for available receivers. Once a receiver is found, this beam is converted with high efficiency back into electricity. The beam is narrow enough to entirely fit on a small receiver. Transmission stops immediately if the beam is broken, and resumes when the obstruction is gone. Safety regulations are met worldwide.

But as an OEM you may appreciate this complexity, but ultimately just enjoy the interface simplicity. Sometimes, integrating with Wi-Charge is as simple as plugging in a USB cable. We found that our self-contained power receiver makes for very simple evaluation and integration.

I think this ‘deceptively simplicity’ was one reason that Wi-Charge was awarded the prestigious “Best of innovation” mark at CES 2018. We can’t wait to see all the innovation driven by this “Simplexity” in 2019 and beyond.

Saturday, October 20, 2018

Is It Safe?

When we speak to prospective customers, at some point or another we are asked “is the Wi-Charge technology safe?”.

The short answer is: YES, it is.

But let’s dive a bit deeper.

Wi-Charge delivers energy by sending a very thin beam of invisible infrared light from the transmitter to the receiver. 100% of the beam hits the surface of the receiver. This means that 0% of the beam falls on everything else. This is a stark contrast from other long-range wireless power technologies like RF that unfortunately bathe the environment with unwanted radiation.

One great thing about IR is that it has naturally existed on earth since the beginning of time. About 50% of the sun’s energy at sea level is IR, so we and our ancestors have become accustomed to living with IR light. In contrast, RF is relatively new man-made radiation.

Question: “But if there is a thin invisible beam, what happens when I put my hand in the path of the beam?”

Answer: What happens is that the beam immediately stops. Transmission is resumed once the obstacle has been removed. Those that see live WI-Charge demos are invited to try this. Not only do you need see the beam, but you can’t feel it anywhere.

Question: “How does the beam know when to immediately stop?”

Answer: we’ll tell at the right time, and once we are under NDA.

Question: “I understand everything you’re saying, but was this validated by a standards or a safety organization?”

Answer: Yes. In the US, the WI-Charge system was submitted to the FDA (the regulatory agency in charge of light-based products) and was classified as a ‘Class 1 device’ which basically means that it is safe for consumer use without any special precautions. Similar certifications were performed outside the US.

The green areas in the map below show these countries where Wi-Charge meets or exceeds the safety standards for that particular country. If a country is not yet green, it usually means that we did not yet spend the time to verify this.

Product safety is critically important to Wi-Charge and to our customers. That’s why we have invested so much in designing a safe system and in safety and regulatory approval.

Saturday, October 13, 2018

How much wireless power is enough to replace AA batteries?

One exciting opportunity for using wireless power is power delivery instead of disposable batteries. Smart devices – such as smart locks – require frequent battery changes. Replacing batteries is inconvenient – whether because one needs to always buy batteries, or because the process of replacing the batteries takes time and effort.

Some have suggested that the adoption of smart battery-operated devices could be accelerated if batteries were not needed. Customers are sometimes worried that if they forget to change batteries on time for their smart lock, they might be locked out of their own home.

If disposable batteries were no longer needed, there would be environmental benefits. Whether because of cost or capacity, most batteries purchased are disposable, not rechargeable, and these end up in landfills as toxic waste.

Additionally, device manufacturers report that some exciting features for these smart devices are left out of the product because of battery constraints.

In short, the ability to use wireless power instead of batteries is valuable to everyone, but how much wireless power is needed to replace a battery?

Many smart home devices use multiple AA batteries. AA alkaline batteries typically have a capacity rating of about 2500 mAh (milliampere hour) and AA NiMH batteries have capacities of only 1200 to 1900 mAh. Let’s assume 2500 mAh. Given a nominal voltage of 1.5V, this translates into 2500 x 1.5 = 3750 mWh (milliwatt hour). A high-end device might have 8 such batteries for a total capacity of 30000 mWh and might need battery replacements every 3 months.

But what if we provided this via wireless power? Let’s assume a small rechargeable battery is built into the lock. That rechargeable battery can provide power if the wireless power is not available (for instance, during a power outage) and also to provide occasional peak power when a high-current activity such as turning the mechanism of the lock is required. The rechargeable battery is then charged through the wireless power.

Let’s examine this using a wireless power system that can deliver 150 mW (this is the low-end model of the current Wi-Charge line). Every hour, such system can deliver 150 mWh. In a day, it can deliver 3600 mWh. Thus, the 30000 mWh – what 8 AA alkaline batteries can provide over 3 months, can be delivered in just over 8 days with a low-end Wi-Charge system.

What are the implications?
  • A wireless power system can easily replace batteries for high-end smart home devices
  • A single wireless power transmitter can charge multiple devices. For instance, a smart lock, a security camera, a smart thermostat, etc.
  • Manufacturers using wireless power can unlock new and exciting features on their devices, now that the energy constraints are removed.