This smart lock never runs out of battery — because I shoot it with lasers

One morning last month, I walked into my kitchen to get a glass of water, but my smart faucet was out of battery. I went to sit down in my front room, and the shade was still shut — it was out of battery. I walked down the hall and found a beached robot vacuum — out of battery. I headed outside to feed the chickens, unlocking the back door on the way out. The battery-powered smart lock had done what it was supposed to and automatically locked at 8PM. At least something was working.

The game changer here is wireless charging. Not wireless like putting your phone on a charging pad, wireless like across the room. For the past year, a Wi-Charge transmitter in my ceiling has been shooting infrared lasers at a photovoltaic panel on the specially modified Alfred DB2S smart lock on my back door, keeping its battery hovering at 100 percent. So I never have to deal with a dead lock when going to feed my chickens.

To get this souped-up setup cost around $1,250, required cutting a hole in my ceiling, and is only available through an early access program (the Wi-Charge-compatible Alfred lock can’t be purchased off the shelf). However, despite this extra effort, after a year of living with a wirelessly-powered smart lock, whose battery I never have to mess with, I want this for everything in my smart home.

I want the convenience of battery-powered gadgets: no cords cluttering up my house, no pricey electrician bills, the freedom to put things where I want, unrestricted by power outlets. I want the benefits that come with battery-powered connected gadgets like smart faucets and shades: voice control, schedules, hands-free operation — without having to spend a day every month recharging or replacing batteries. In short, I want wireless power everywhere.

Long-range wireless power has been a dream for over a century. Wi-Charge (pronounced WHY like wire) has been working on its solution for the better part of a decade, debuting it at CES in 2018. Based on my experience, the technology works. But I’m less bullish on whether the infrastructure will ever exist in the home to make this more than just a curiosity or niche luxury.

Wi-Charge’s AirCord technology uses infrared lasers to beam power from its R1 wireless power transmitters to a receiver within line of sight. The standard transmitter, which I tested with the door lock, can deliver 100mW to devices within 10 meters; there’s a higher-powered one that can send 300mW at up to 5 meters. One transmitter can juice up multiple devices, powering one at a time.

Should I be worried about having infrared lasers bouncing around my home? Wi-Charge says no. The company has Class 1 FDA approval for a laser product, which means it should be as safe to use as a DVD player. Still, I rarely look directly into a DVD player. The transmitters are also FCC-certified (because they use Wi-Fi to connect to the Wi-Charge cloud) and UL-approved. (It doesn’t directly connect to 110V, so doesn’t need to be UL-listed).

The transmitters use a low-powered laser to locate the receiver and switch to high power for charging once the connection is established. When I walk under one, it cuts off the transmission, resuming it once I’ve passed through (indicated by a small LED status light). “100 percent of what is sent reaches the receiver, there is zero emission outside the beam, and people are not exposed to any infrared,” Ori Mor, founder and chief business officer of Wi-Charge, assures me.

While we weren’t able to independently verify the safety claims, I still have my sight and have had two Wi-Charge transmitters in my house for a year now — one for the Alfred lock on my back door and the higher-power R1HP model in the ceiling of my bathroom, powering an electric toothbrush charger. The toothbrush charger is a prototype and not for sale, which is a shame, because it’s excellent. Bathrooms are precisely the type of place you don’t want to be dealing with wires.

Alfred’s DB2S is the Canadian manufacturer’s second smart lock to work with Wi-Charge (the first was the ML2, a US mortise-style lock for commercial buildings). A deadbolt lock with a sleek, modern look and a high-quality build, DB2S has most of the features you’d expect in a smart lock, including a touchscreen keypad, a keyway for unlocking, and the option of two RFID keyfobs.

It works over Bluetooth and Wi-Fi (with a separate $60 bridge) to connect to Alfred’s app for managing keycodes and controlling the lock, as well as connections to Amazon Alexa and Google Home. There’s also the option of a Z-Wave module for compatibility with platforms such as Samsung SmartThings and Ring Alarm. While the lock cost $299 when I reviewed it, and can still be found for that price, Alfred recently raised the MSRP to $320, due to the impact of tariffs.

As a smart lock, it worked reliably. The keypad is easy to use, the lock responds promptly, and I liked its GPS auto-unlocking feature. Overall, it’s a solid, albeit expensive, smart lock, but it’s the Wi-Charge integration that makes it noteworthy.

Out of the box, the DB2S is not set up for wireless power — you need to request a Wi-Charge/Alfred conversion kit by filling out a form on Alfred’s website. Alfred’s Brad Cook tells me that pricing for the conversion kit and transmitter ranges from $499 to $799, depending on your setup — that’s in addition to buying the lock.

The kit I tested consisted of a Wi-Charge transmitter with a ceiling mount and a new backplate for the lock that included a modified replacement 2200 mAh lithium-ion battery. The backplate is significantly larger than the one the lock came with, incorporating an infrared-optimized photovoltaic panel built into the top. It looks a bit like the chonky remote for your old TV.

I had the transmitter installed in the ceiling three feet from my back door. It’s small and unobtrusive, measuring approximately 4 inches wide and 1.5 inches deep. It has a wide glass panel that transmits the infrared laser to the receiver, and it’s powered by a 12-volt barrel connector connected to my mains power via a modified ceiling light fixture supplied by Wi-Charge.

In theory, I could have just installed the transmitter where there was an existing can light, but the Wi-Charge team was concerned that the angle of the lights in my hallway wouldn’t be optimal, so recommended installing a new can in a more central area. This cost $450 for an electrician to cut a hole in the drywall and extend a circuit from the existing lights.

All in, the price for the privilege of never having to mess with the battery on a single smart lock was around $1,250. Is it worth it? No. Could it be in a future where the tech costs less and can do more? Totally.

Once installed and up and running, I evaluated the Wi-Charge device by putting a fully charged battery into the lock and using it regularly for nine months, locking and unlocking it using the keypad and via a schedule that locked the door automatically every night. The battery never fell below 100 percent.

I then unplugged the transmitter and taped over the infrared receiver on the lock, continuing to use it normally. After about three months of intensive use, the battery was down to 58 percent. I uncovered the infrared receiver panel for a week to see if the lock would recharge at all using ambient light; it didn’t. I then plugged the Wi-Charge unit back in, and the battery started charging again. It went up to 68 percent in a day, 78 percent in three days, and was at 90 percent after a week.

It was impressive. I test a lot of smart locks, and the number of times I’ve tried to unlock my back door only to be faced with a dead lock is surprisingly high. Most can only go three to six months before needing new batteries, and that can get tiresome.

The Alfred uses Bluetooth LE, rather than power-hungry built-in Wi-Fi, so it can go a bit longer — Alfred claims nine to 11 months — but it’s still a pain to fiddle with batteries. Alfred’s Cook explains that Wi-Charge’s power management algorithms optimize the charging cycles, so it’s not constantly pulsing electricity; instead, it sends power only when needed. All of which make Wi-Charge an excellent, if expensive, solution to a particular smart lock problem.

However, Mor says the Wi-Charge system can power anything with a rechargeable battery. That includes smart locks, smart shades, smart faucets, security cameras, and even smart speakers and smart displays if they have a battery. If the puck in the ceiling of my hallway was also powering the smart shades and security cameras nearby, it would be a much better value proposition. Extending beyond smart home devices, imagine never having to plug in your game controller or swap the batteries in your TV remote, or being able to wirelessly power your VR headset.

But in order to be powered by Wi-Charge, a device needs a receiver, and for most products, that means a complete redesign. Mor says they are developing a receiver that can plug into any device with a charging port, but I don’t want dongles in my wireless future. And, as the receiver needs line of sight, I’d need several transmitters around my house to power all my gadgets.

The good news is that the transmitters are flexible, installation-wise. Along with the ceiling light option, you can also wall-mount it, install one in track lighting, and there’s a model that can be placed on a shelf — so no need to mess with drywall.

While I can confirm that wireless power over a distance actually works, it still feels like the dream of whole-home wireless power may be stymied by infrastructure. Companies just aren’t going to invest in putting receivers in their products unless people demand them, and people aren’t going to install wireless power transmitters unless they have something to power with them.

Where wireless power likely has the most potential — and where Wi-Charge has had the most success so far — is in commercial applications where there are lots of devices to charge. For example, digital posters, electronic signage in stores, or other digital displays where hardwiring is difficult and changing or recharging batteries would be expensive and time-consuming. A Wi-Charge unit can power many electronic price signs, and the lack of wires means it’s easier to move them around.

Of course, there’s also the question of efficiency. Wireless charging is significantly less efficient than using wires or batteries, or even magnetic induction. You’re converting electricity to infrared light, shooting it through the air at a photovoltaic panel, and turning it back into electricity to charge a battery.

When actively charging — which Mor says is about 1 percent of the time — the transmitter uses about 5W of power to get a steady 100mW output from the receiver.

Mor says Wi-Charge’s wireless power transfer efficiency is about 15 percent compared to a direct wired connection. That’s not counting the energy used to power the transmitter’s Wi-Fi connection, status LEDs, and so forth. He claims it’s more efficient than any other line-of-sight charging, but about four and a half times less efficient than magnetic induction (Qi) charging.

However, devices like locks, shades, and so on use very little power overall, meaning the total increase in electricity use should be minimal. Based on a $0.20/kWh electricity cost, Mor says that over a year, the Alfred lock would cost less than $0.10 to power wirelessly, compared to less than a cent to recharge with a USB cable.

If I could power all the other battery-powered devices in my home at the expense of a few pucks in my ceiling and a dollar or so more a year in electricity, I would do it. Ditching wires, charging docks, cables, and disposable batteries to power door locks, electric toothbrushes, smart faucets, shades, remote controls — maybe even more power-hungry gadgets like battery-powered security cameras — could be a game changer in the smart home. Sadly, I’m not sure if it’s a game anyone else is ready to play.

Photos by Jennifer Pattison Tuohy / The Verge