Shootout: Fastest charging phones
PUBLISHED ONJune 30, 2015 8:35 AMByJames Lu
Overview
As smartphone displays have grown in size and resolution, so too has battery capacity to meet the increased power draw. Unfortunately, despite larger batteries, battery life still struggles to accommodate the needs of heavy-usage smartphone users and, as such, reducing re-charge times has become the next best thing. Over the past few years, a number of companies have introduced innovative technologies that speed up the charging process. But which solution is the best? Let's find out.
Fast Charging Explained
Before we begin, a quick note on how chargers work in general. How fast a battery charges is determined by how much power it receives from the power source (normally a wall outlet), through the charger, to your phone. Your phone also includes built-in regulators to prevent pumping too much power into the battery and frying it. The actual amount of power output from the charger is determined by the voltage (measured in volts) and current (measured in amps) that it is rated for safe use.
Not all chargers output the same volts and amps. A standard phone charger will output around 1A at 5V for a total of 5W of power. If you charge your phone by connecting it to a USB port on your laptop, you're looking at 0.5A at 5V for 2.5W of power on a USB 2.0 port, or 0.9A at 5V for 4.5W of power on a USB 3.0 port, which basically means that if your phone can handle anything above 0.9 amps (it almost certainly can), a USB port will charge it more slowly than the charger that came with the device.
Basics aside, let's take a look at the various fast charging standards available:-
Qualcomm Quick Charge
The most prevalent fast charging technology available today is Qualcomm's Quick Charge tech, which has been around since 2012. Qualcomm's technology is designed to maximise charging efficiency by delivering a higher power load. Quick Charge 1.0 made use of a 2A/5V charger, resulting in 10W of charging power, which is double the conventional 1A/5V chargers. Obviously, only phones with higher internal regulators were able to make use of Quick Charge 1.0, and you could find it on the Samsung Galaxy S III, LG Nexus 4 and Optimus G, and Xiaomi Redmi 2, as well as a few others.
In 2013, Qualcomm introduced Quick Charge 2.0 on Snapdragon 800 chipsets, which allows for an even higher level of power transfer between your power source and device. There are actually three different specifications of Quick Charge 2.0 chargers: 3A/5V, 1.67A/9V, and 1.25A/12V. However all three deliver 15W of power.
Plenty of the latest devices support Quick Charge 2.0 including the LG G4 and G Flex 2, HTC One M9, Samsung Galaxy Note 4 and Galaxy Note Edge, Sony Xperia Z3 and Z3 Compact, and Xiaomi Mi 4i. However, out of all the phones listed, only the Samsung and Xiaomi phones include a Quick Charge 2.0 charger in the box. The other devices all come with generic chargers, and you'll need to purchase a compatible Quick Charger separately. If you do end up buying a Quick Charge 2.0 charger, do note that all devices compatible with the Quick Charge 2.0 standard can safely use any Quick Charge 2.0 compatible charger - the technology inside them is the same. Don't be fooled into buying an expensive branded one that matches your phone brand, as it won't charge any faster.
Oppo VOOC Flash Charge
While Oppo uses Qualcomm's chips in its phones, it has its own quick charging innovation that's quite unique. It's called VOOC Flash Charging, which stands for Voltage Open Loop Multi-Step Constant-Current Charging.
While VOOC chargers also deliver a higher power load than standard chargers - the current second generation VOOC mini chargers deliver 5A/5V for a whopping 25W of power - Oppo also uses a different battery structure in each of its phones. VOOC-enabled phones consist of several individual battery cells, and the high 5A current is split among those. Due to this, the battery has a higher number of contacts than usual, with each cell charged simultaneously. Most of Oppo's latest smartphones are VOOC compatible, including the Oppo N3, R5 and Mirror 3. All VOOC-enabled Oppo phones come with a compatible charger in the box.
Samsung Adaptive Fast Charge
Samsung's Fast Charge technology, found in the Galaxy S6 and S6 Edge appears to be exactly the same as Qualcomm's Quick Charge 2.0 technology. The charger that ships with both the Galaxy S6 and S6 Edge is rated to the exact same 1.67A/9V specifications as Qualcomm's Quick Charge 2.0 chargers. We also tested the S6 with the charger supplied with the Galaxy Note Edge, and it appears to work just fine. It's possible that Samsung simply modified Qualcomm's technology and adapted it to work with its own Exynos chips.
ASUS BoostMaster Technology
ASUS' BoostMaster technology, found in its ZenFone 2 series of phones, also appears to use a similar technology to Qualcomm's Quick Charge 2.0. The charger supplied with the phone is rated at 2A/9V, supplying a maximum of 18W of power. Despite using an Intel Atom processor, the ZenFone 2 will also fast charge using a Qualcomm Quick Charge 2.0 charger or even a Samsung Adaptive Fast Charger.
Which phone is the fastest charger?
For this shootout, we've selected a wide variety of smartphones with fast charging capabilities, including flagship smartphones and phablets, as well as mid-range options. We also threw in the non-fast charging Apple iPhone 6 as a baseline measurement.
To test the phones, we completely drained their batteries, then plugged them all in to the same power strip at the same time recording their power levels after 15 minutes, 30 minutes, and finally when they reached 100 per cent charge. For each phone, we used the charger supplied in the box with the phone, with the exception of the LG G4, which uses a Quick Charge 2.0 charger supplied to us by LG. The phones remained off for the duration of the charging.
Performance findings
The Oppo N3 was the fastest charger at both 15 and 30 minutes, which is especially impressive considering its large 3,000mAh capacity battery. Despite having by far the smallest battery, the non fast charging Apple iPhone 6 fell way behind, and was actually at a lower battery level after 30 minutes than the N3 was at 15 minutes.
The first phone to reach 100 per cent charge was the Samsung Galaxy S6, although it's worth noting that it also has the smallest capacity battery out of all of our fast charge enabled phones. The N3 was second.
No matter what fast charging technology was used, all of the phones slowed down considerably after they passed 60 per cent charge. The Xiaomi Mi 4i in particular had a huge drop off, taking just 45 minutes to reach 50 per cent charge, but more than two hours to reach 100 per cent!
In terms of overall battery life, the Oppo N3 was also the winner, lasting just over ten hours in our standard video looping battery benchmark test.
Conclusion
If you had any doubts about fasting charging before, they should be gone now. Fast charging, no matter the technology used, is great and doesn't appear to have any noticeable drawbacks. We haven't heard any reports of shorter overall battery life associated with fast charging devices, and other than some extra heat generated during the charging, there are no other noticeable side effects. If you're worried about exploding phones or fried batteries, you shouldn't be, as the power regulator inside your phone ensures that the battery will never receive more power than it can handle (although do avoid suspect generic chargers offering fast charging as there's no telling if the charger itself will burst into flames). Note that it's also perfectly safe to use a fast charger with a non-compatible device - just know that it won't charge any faster than it did previously.
The winner of our shootout is the Oppo N3 and its VOOC Fast Charging technology, which can also be found in most of Oppo's other smartphones. The huge power delivery, combined with Oppo's unique battery cell structure makes it by far the fastest charging smartphone, and it doesn't seem to have any negative effects on how well the battery holds its charge either, as the N3 also had the longest battery life.
Visit Hardware Zone for more stories.