How to choose a mains charger

The need to buy a charger is not so rare: regular “charging” can be lost or broken, and for some time now, many gadgets do not have a charger at all. However, not every charger will fit every gadget. You should make sure that its characteristics correspond to the parameters of the device being charged.

Characteristics of mains chargers

The connection connector is the first thing that determines the compatibility of the charger with the one being charged. Fortunately, the days when each manufacturer provided their gadgets with a unique connector are a thing of the past, and most modern devices use a micro USB or USB Type-C connector. The chargers for such gadgets usually have a USB or USB Type-C connector and a detachable cable included. Occasionally there are chargers with a micro USB connector on a non-removable cable. But this does not give them any advantage, on the contrary, it makes them less universal.

Although there are adapters from USB to USB-C, and vice versa, it is advisable to select the connector on the memory unit the same as on the gadget. Despite the common data transmission standard, the number of pins on these connectors is different. The information transmitted by the additional pins of the USB-C connector in the USB adapter is emulated using resistors or jumpers.

Using an adapter cable instead of a straight cable for charging will, at best, result in fast charging protocols not working. But the charger can also burn out, in the worst case, “pulling” the gadget along with it.

There are chargers with more than one USB connector. These can charge multiple devices at the same time.

Output current per port
Before version 2.0, the USB connector could supply no more than 500 mA, and even many modern gadgets are designed for such a supply current. An average smartphone battery with a capacity of 3000 mAh will be charged with such a current for 7-8 hours, although it can “take” currents up to 3 A, or even higher, without harm to itself.

The more output current per port, the faster the charge will go. However, chargers with a current per port above 3A are rare. The fact is that the USB standard was developed for data transfer, and not for power. USB wires are thin, have high resistance, and as the current increases above 3A, the voltage drop in them becomes too large.

The current of the charger must match the capabilities of the gadget. Usually, the required charging current is given in the manual for the mobile device. If the output current per port is more than required, it’s okay – the gadget’s charge controller will protect it when connected to an overly powerful charger. Otherwise, when connected to a “weak” charging device that can be charged with high current, the charging time will increase.

For chargers with multiple slots, the output current per port may be less than the total maximum output current

If you connect two devices charging with such a current to a charger with a maximum output current of 1000 mA, both of them will receive only 500 mA each, even if the output current per port is declared to be the same 1000 mA, and they will charge twice as long. The output current per port can be equal to the maximum only when only one device is connected to it, “taking” the maximum current.

output power
Power is the product of current and voltage. In the old USB standard, the voltage is constant and is 5 V, respectively, the power of the memory depends only on the current strength. For devices that do not support fast charging, power is synonymous with charging current. The more power of the memory, the faster the charging of the gadget will go. Of course, if the gadget is able to accept this power. If on most memory devices the output current per port does not exceed 3A, then the power should not exceed 15 W? Not certainly in that way. Fast charging protocols allow you to increase the voltage in the USB connector to 22V, thus raising the power to 60 W or more – up to 120 at a current of 5 A.In reality, compact memory devices with an output power of more than 45 watts are rare. The reason is the imperfection of technology. Power microelectronics simply cannot withstand such currents. The latest development in this area is gallium nitride (GaN) power semiconductors. They have a much higher power density and allow you to lay down to create chargers up to 80 watts. Unfortunately, the technology is still expensive, which is why such memory devices are not cheap.

fast charging
The inability to increase the charging current led to the emergence of fast charging protocols that allow the memory controller to “negotiate” with the gadget’s power controller to increase the charging voltage.

Depending on which of the fast charging standards is supported by both sides, the charger outputs an increased voltage of 9, 15 or 20V. In the power controller, the voltage is reduced back to 5 V with a corresponding increase in charging current. Take, for example, a smartphone with a 4000 mAh battery. When charging from a conventional charger with a maximum output current of 2 A, the battery will charge for 2 hours. And when using fast charging with a maximum voltage of 20 V, the same smartphone will be charged in 30 minutes, since the charging current will be 4 times higher.

Fast charging often involves the use of currents of 2C or more – 2 or more times the battery capacity. For early batteries, this mode quickly led to a loss of resource. Fast charging also affects modern batteries not in the best way – with constant charging with a current of 2C, a decrease in battery capacity by 20% is noticed after 500-800 charge-discharge cycles. Is it worth giving up fast charging because of this? Unlikely. Even with daily charging, it is 2-3 years before the decrease in battery life becomes generally noticeable.

There are many standards for fast charging, and for them to work, it is necessary that both the charger and the device being charged support the same standard. Therefore, if you plan to use the purchased charger to quickly charge your gadget, make sure that it supports the required standard:

Quick Charge is Qualcomm’s standard and has been supported by devices based on Snapdragon chipsets since 2013. The maximum current in the latest version of the standard is 5 A, the maximum voltage is 22 V, which gives more than 120 W of theoretical maximum power. In practice, such power is not supported by real devices, and standard memory devices give out only 18 watts. The first versions of the standard did not provide for temperature control, which caused many cases of overheating during fast charging.

Adaptive Fast Charging – for charging Samsung gadgets since 2015. It is based on Quick Charge 2 and is partially compatible with it, so you can charge gadgets with Adaptive Fast Charging support from a charger with QC 2 support.
Huawei Fast Charge and Huawei Super Charge , as the name implies, is used on Huawei devices. The standard is also based on Quick Charge 2. The maximum power of the memory with support for this standard is 18 watts.
MediaTek Pump Express was developed by the company of the same name and is supported by modern smartphones based on the SoC of this manufacturer – many Chinese smartphones are such. The standard is also based on Quick Charge 2, and is fully compatible with it. The power of memory with support for this standard is limited to 15 watts.
Super Fast Charge is Samsung’s fast charging protocol, supported on high-end smartphones and based on Power Delivery 3.0. Declared support for maximum power up to 25 watts.
PowerIQ is a Quick Charge-based standard supported by Anker charger manufacturer. PowerIQ is compatible with most fast charging protocols, allowing you to quickly charge any gadgets from a charger that supports the standard.
Power Delivery is the most promising fast charging protocol developed by the USB Consortium in 2015. Currently used by Apple, Xiaomi, Sony gadgets. Quick Charge version 4.0 is also fully compatible with Power Delivery. The standard supports supply voltages up to 20 V and current up to 3 A, which ultimately gives up to 60 W of power. It is part of the USB 3.1 standard. In fact, any device with a Type-C connector must support PD for charging.

AC charger options
A charger with a USB A connector is the most versatile type of “charge” today. Most mobile devices can either be charged from this connector, or have an adapter for it.

If you want to charge several devices at the same time, choose among chargers with multiple ports .

UCB-C threatens to become the main charging connector in the near future. If your gadget is equipped with USB-C, do not use an adapter with USB A, but choose among the memory with the appropriate connector.

To speed up the charging of the gadget, use a charger that supports fast charging . Just make sure that your gadget supports the same standard and use the “native” cable.

To charge gadgets with high-capacity batteries (tablets, laptops), choose among high-capacity chargers – they are able to “give” high current and voltage.