Meet The Man Behind OPPO's Super Fast Charging Speeds

2018-11-22

The biggest gripe I have with the new iPhone has nothing to do with its performance during active use, but rather when I'm not even touching the phone.

The new iPhone XS can support fast charging up to 30 watt, but the charging brick Apple includes with the $1,200 phone is a putrid 5w plug that takes over three hours to fully charge. The larger Max needs another half hour on top of that.

In the Android space, a fast-charging brick included in the packaging is just about standard, and every single big brand Android I've tested this year can fill up in one-third of the time (or less) it takes to charge my iPhone.

But while Huawei and Qualcomm offer pretty speedy top-ups (it takes about 45 minutes to charge a Huawei Mate 20 Pro, and an hour and 10 minutes for a Samsung Galaxy Note 9, respectively) none are as amazingly fast as what I get from Oppo's and OnePlus' phones.

The special Lamborghini edition of Oppo's Find X can go from 0 to 100 in 35 minutes. Even my less-premium standard Find X can fully charge in 45 minutes. My OnePlus 6T, likewise, can top at similar speeds. Even if I were to invest in the official Apple fast charging gear for the iPhone (which costs over $50 for a USB-C charging brick and Type C to Type C cable), the iPhone XS's absolute best charging speed is still around an hour.

And when you consider that the Oppo Find X and OnePlus 6T both have larger batteries (around 3700 mAh) than the iPhone XS (around 3100 mAh), that makes the difference in charging speed even more pronounced, because the iPhone has less battery capacity to fill.

Oppo and OnePlus are able to achieve best-in-class charging speeds because the charging tech used is an anomaly in the industry. Most other fast charging tech -- from from Qualcomm's Quick Charge to Apple and MediaTek's version, use high voltage, low current to pump juice into devices; Oppo and OnePlus phones instead goes the opposite direction with low voltage, high current power transfer.

And it was all one quirky man's idea.

Two sides of the same coin

Let's clear this up first: to the outside world, Oppo and OnePlus are completely separate brands. That they cater to different regions (up until recently, Oppo was mostly China-centric, while OnePlus has been popular in the west from the start) means very few "normal consumers" have access to both brands. So for the most part, each brand had been advertising its fast charging tech as separate entities and did not acknowledge each other. Oppo calls its tech "VOOC" (Voltage Open Loop Multi-step Constant-Current ); OnePlus initially called its version "Dash," until copyright issues with another company led to the scrapping of that name.

But make no mistake: VOOC and the Charge Formerly Known As Dash are almost the same thing. I can use an Oppo brick and cable to top up the OnePlus, or vice versa, and attain the same max charging speeds.

The official story here from Oppo's side is that it licensed VOOC's tech to OnePlus. But the open secret that everyone who covers the phone industry knows is that Oppo and OnePlus share the same parent company and components.

Fast, not furious


In electricity, voltage is the cause, and current is the effect. Voltage is the force that pushes current from point A to point B -- like the horsepowers of an engine pushing a car forward. Current, meanwhile, is the rate at which electric charge flows through a circuit point -- like the actual speed of the moving car.

As mentioned earlier, all the major charging tech in consumer electronics right now focuses on high voltage, but Oppo's VOOC instead prioritizes current. This is akin to other carmakers focusing on ramping up horsepower, while one decides to focus on helping its car attain efficient top speed as its moving.

The idea to flip the script and go against the grain came from Zhang Jialiang, an engineer at Oppo, in 2012, when the then-35-year-old concluded that the high voltage, low current charging solutions of other brands were using had a ceiling.

"High voltage charging is inherently constrained by the laws of physics," Zhang, who is affectionately known as Jeff to English-speaking colleagues, says. "Because there's only so much power you can push through before the current bottlenecks while entering the phone, resulting in heat buildup."

Instead, Zhang decided a more efficient, and potentially safer, method is to stop focusing so much on pushing for higher voltage, but instead use smart solutions to help the flow of electricity gain speed and efficiency.

To do so, Zhang and his team build a "smart" charging head to keep voltage in check before entering the phone's circuit board. The excessive current was then solved by using a thicker, wider charging cable.

To use another driving analogy, this is like increasing the lanes in a highway to ease traffic jams instead of asking cars to just drive faster.

But here's the thing, Zhang's idea initially was rejected by everyone else at the company.

"My colleagues asked, 'if Apple, Samsung, Huawei and Qualcomm are all doing things one way, why do we need to do it differently," Zhang says. "Not to mention my method would increase production cost of the charging brick and cables."

The lack of official support or access to resources didn't deter Zhang. Having been with Oppo since 2004 -- when the company was a maker of MP3 players -- Zhang had build up enough clout with the company to work freely. So he began developing his low voltage, high current charging tech after work hours at Oppo's research center in the southern Chinese city of Dongguan.

Zhang convinced fellow colleagues, including one who now works at OnePlus, to join his secret pet project. The four would stumble along the development process with plenty of trial and error. Because of the unauthorized nature of their project, they could only use the lab after work hours, and had to purchase items for testing (such as a controller chip from Fairchild), out of their own pockets.

A year later, Zhang and his team showed off a working prototype of VOOC to the same colleagues who initially rejected the idea. Impressed with the results, Oppo's COO and Zhang's direct boss, Mac Zeng, approved the tech to be implemented into Oppo's 2014 flagship the Find 7.

The at-the-time unrivaled 50-minute from 0 to 100 charging speeds of the Find 7 drew immediate praise from reviewers, but Oppo phones at the time were still mainly used in China and Southeast Asia. It wasn't until OnePlus -- which has a cult following in the U.S. and Europe -- adopted the tech in 2016 on the OnePlus 3 did the superior charging speed get widespread English media acclaim.

Not only does Zhang's low voltage, high current solution top up faster, but the phones do not get hot during charge. On devices using Qualcomm's Quick Charge solution, the phone heats up significantly during charging. If you're gaming and charging, say, a Samsung Galaxy phone at the same time, the heat could get worrisome, especially after what happened with the Note 7 and all.

There are shortcomings with Zhang's low voltage, high current solution: Oppo and OnePlus phones must use the same charging brick and cable to achieve the speed. If you are charging your phone at a friend's house, and he doesn't have an Oppo/OnePlus charging brick and cable, you'll charge at a much slower rate.

Splitting the difference

Since the Find 7 debut, VOOC has been improved by Zhang and his team. As mentioned, Oppo's Find X Lamborghini Edition and the recently released R17 Pro can go from dead battery to fully charged in 35 minutes. This version, dubbed "Super VOOC," uses a bi-cell battery design to achieve the insane speed.

The idea behind it is clever, but simple. Batteries recharge faster in the middle portion -- the jump from 40 to 50% is faster than 90 to 100% -- because the charging tech knows to begin winding down charge. Again, to use a driving analogy: a race car's peak speed is in the middle of its run, not at the beginning or near the finish line.

By splitting its 3,700 mAh battery into two cells, the charging process gets to the "middle" part of the charge earlier.

Of course, the elephant in the room is that premium flagship phones are all moving towards wireless charging -- a path Oppo and OnePlus have not followed yet -- and it is fair to question that as users adopt wireless charging more and more, will Oppo's wired charging tech be considered outdated.

Zhang isn't concerned. For one, it is unlikely wireless charging will ever catch up to the speeds of wired charging, so while wireless charging may be good for overnight charging or those who have their phone sitting on a desk all day at work, for moments when you need a quick top up (say, making a quick stop at home in the evening before heading out for the night), everyone will still prefer to use cables for faster charging.

Plus, Zhang says he and his team are actively working on fast wireless technology, and "there have been breakthroughs already." He's not ready to announce anything yet, but it might just be something drastically different from what everyone else is doing again.


From Forbes.com

Reporter Ben Sin