Surely all users of mobile devices want the battery not only to work as long as possible, but also to charge as quickly as possible. But there is one problem – peak charging power has been steadily increasing lately, but the laws of physics say: the more current is charged, the higher should be the battery heating, which means that the battery will lose capacity faster with a large number of charge/discharge cycles. However, it is not all so unambiguous, because the creators of devices with fast charging are doing everything possible to significantly reduce battery degradation and make the devices safer in general. For more details, see the article by Gennady Yagupov.
Fast charging standards
Qualcomm’s Quick Charge is considered the best-known standard for fast charging. Its first version, introduced back in 2013, was designed for only 10 watts. For many budget smartphones, it is still the most common option. Sometimes even slower chargers can be found. But the technology of the American company did not stand still: as it developed, it received more and more power and compatibility with other charging profiles. The QC 4.0 and 4.0+ versions began working with Power Delivery and USB-PD 3.0 PPS profiles, respectively. In July 2020, the new Quick Charge 5 was introduced, delivering more than 100 watts of power, of course, if the standard is supported by the devices in use. But either way, devices will take as much as they need. There is no need to fear overvoltage or other problems.
For devices running on chipsets from MediaTek, the popular charging standard is Pump Express, which works in about the same way as the analog from Qualcomm: in the new versions there is a step voltage regulation. At the same time, it is not the fact that some smartphones with PumpExpress technology will be able to charge quickly when using power supplies with QC support, although it is stated that this problem is eliminated in the new Pump Express 4.0 standard due to support for Power Delivery 3.0.
So what is Power Delivery? It is the most universal standard, allowing you to charge not only smartphones and tablets, but even laptops. It can also power modern monitors. The power charging reaches 100 watts or more.
At the same time Power Delivery is absolutely safe due to full compliance with USB specifications and solves the problem of a variety of connectors. In fact, the Type-C port, which is used in conjunction with Power Delivery, now have no only budget and outdated devices, as well as mobile equipment Apple, but probably only temporary problems.
Announced in July 2020 OPPO 125W Flash Charge was an incredibly powerful solution, capable (so far only in theory) in about 20 minutes to charge the battery capacity of 4000 mA*. But we can safely assume that the manufacturers will not stop there and will increase the figures.
There is an analogue called Realme 125W UltraDart Fast Charging, but in many ways the technology is similar: they require a special power supply and a double cable capable of withstanding enormous loads without significant voltage sags.
For now, less powerful variants are more common in smartphones – VOOC, SuperVOOC 2.0, SuperDart, etc. For example, SuperDART Charge is compatible with Quick Charge and Power Delivery. With 65 watts of power it can charge a 4,500 mA*h battery in less than forty minutes. It claims to support chips that control temperature and are responsible for overall charging safety, keeping the battery from getting hotter than 40° C.
There are a lot of other standards – Samsung Adaptive Fast Charging, Motorola TurboPower, Dash Charge, Huawei SuperCharge, mCharge and their modifications, but they could not offer something unique.
How fast charging works
Despite occasional news that revolutionary solutions which will soon last much longer than traditional batteries, lithium polymer (Li-pol) batteries are still the standard in mobile technology.
They consist of a cathode, an anode and a polymer electrolyte with dissolved lithium salts. During charging, lithium ions intercalate into the structure of the anode, while during discharging the ions penetrate into the cathode. And here you should understand that any charging, even with a small current, somehow contributes to the degradation of the battery as a result of natural processes. The anode is constantly interacting with the electrolyte, which leads to loss of capacity, but the electrolyte itself also degrades.
There are a huge number of power supplies that indicate charging at 9, 10, 11, 20 volts and so on, but the battery itself is supplied with a standard value of 4.2 volts, while everything else is converted into current.
Oppo and TÜV Rheinland conducted tests of fast charging in their laboratories. They concluded that after 800 fast charging cycles, the initial capacity of smartphone batteries decreases only slightly – by about 9%. Whether it is worth believing such data, everyone decides for himself. In any case, the tests were probably conducted under optimal laboratory conditions, and in real-world usage scenarios, things might not be so rosy.
Is overheating dangerous during fast charging
The main cause of battery wear and tear is the heating of the batteries during charging and the large number of charge/discharge cycles used. It would be reasonable to assume that it is the fast charging options that are most dangerous. In theory this is true, but there are some interesting solutions to combat heat. For example, some devices have started using two batteries connected in parallel. When the current is distributed over several cells, each cell heats up less and charging becomes faster.
At times, users tend to blame fast charging for absolutely all the sins, especially if there is a significant reduction in the life of the device. But it is necessary to remember about some rules of use. First of all, do not let the device overheat: do not leave it for a long time in the sun or in very warm places, do not cover it with anything while charging and do not allow overcooling.
Mechanical damage can lead to battery bloating and more serious problems, up to and including fire and explosion, which means you should be careful when using the device, although in almost all cases the body will take the brunt of the impact. The battery can also be damaged when disassembling smartphones and tablets. Therefore, in any case, do not repeat what, starting from the sixth minute, does the author of the video below.
It is not recommended to use mobile devices while charging, especially for complex tasks like running heavy applications and games. First, there is a considerable risk of loosening the charging connector over time, even if it is a modern Type-C. Secondly, the device running at full power will create an additional load and lead to higher heat, and it is not yet known how the chips that control the temperature will cope with this problem.
But leaving the charging smartphone overnight is acceptable, as charging will automatically stop when the battery reaches maximum. But there is an opinion that you should not charge the battery to 100% (although it is not dangerous), as well as to allow a deep discharge. It is more reliable when the charge reaches about 80%, but with the discharge everything is more complicated, because in different smartphones after the indicator shows 0%, there are different amounts of capacity. But we can say for sure that a discharged device should not be left without recharging for weeks or even months (especially in the cold). The voltage in the battery can drop so low that the mobile device will stop responding to the connection to the power supply.
There shouldn’t be a problem using third-party power supplies or cables either, but note that they can significantly reduce charging speeds as not all protocols are compatible. Cheap, low-quality accessories can heat up a lot and give a lot of voltage drop, which will not be good for your devices and can cause short circuits. Some Chinese budget devices still come with low quality accessories. It is advisable to replace them with more reliable analogues.
At the moment a large number of fast charging standards have already been created, but it is impossible to say unequivocally that all of them are harmful or absolutely harmless. Nevertheless, some manufacturers are finding ways to reduce charging heat, which significantly increases battery life.
Therefore, when buying devices with the latest charging standards, you do not have to fear that the batteries will explode or something will happen to them. Most tragic cases are caused by defects, mechanical damage or improper operating conditions.
In normal conditions, the battery, even with daily charging should last for several years, which is very important, because most modern devices without damage is at least problematic to disassemble. And for some little-known Chinese devices it is difficult or even impossible to find a battery.
Ardent opponents of fast chargers often call to read physics textbooks, but technology is not standing still and no textbook will not tell you about all the nuances of modern chargers. Moreover, some details are kept secret by the manufacturers. Anyway, you can always find a lot of tricks to reduce the negative impact of high power. Some of these tricks were described in this article.
However, for some manufacturers, for example, Samsung and Huawei, in the operating system you can find a feature that disables fast charging, even if it is supported by the power adapter – apparently for those users who doubt the usefulness of this function and want to use their smartphones as long as possible.