Portable phone chargers


The main problem with modern phones and tablets is low battery capacity. Most smartphones have a hard time making it through the evening or sit down at the most inopportune moment. Big screens, powerful 4G and 5G apps all drain your battery and drain your phone at the most inopportune moment. Is there a real opportunity to extend its service life and not get into an unpleasant situation? The solution is simple – use portable phone chargers, recharging it when needed at the workplace, in the car or on the subway. In this article, we will tell you how to choose the right portable charger for your phone and how to use it correctly.


You’ve probably come across a situation when the phone runs out of charge at the most inopportune moment. It is good if it happens at home or in the office, where it can be recharged. But if you went on a trip and use your smartphone as a navigator, if you urgently need to take an important call or check your mail, and it takes several hours to get to the nearest outlet, then only a portable charger or a spare battery will help you, which will have to be charged separately or carried with you. …

Working with a spare battery is not always convenient – the phone will have to be disassembled, replaced, turned off. In some models, the battery is not removable at all, so this trick will not work. Portable charging is preferable for this.

Most chargers are rechargeable batteries that charge from the USB connector and transfer the charge through a cable to the phone. There are also various exotic chargers from a solar battery or a campfire, but they are mainly of interest to tourists. In our article we will focus on the so-called Power Bank, which are colloquially called external batteries. Let’s consider what types of portable batteries for charging the phone are, how they differ and which device you can choose for reinsurance.

What is Power Bank

Power Bank, in fact, is a universal battery suitable for charging any device via USB or mini-USB connector. It is an array made up of several small batteries connected together and packed into a beautiful case. The battery capacity depends on the number of cells, in popular models it varies from 5 mAh to 15 mAh.

The case of the Power Bank can be plastic or aluminum, it has 1-2 outputs, charge indicators, a power button and other additional options. For example, some models have a built-in LED that allows you to use the Bank as a flashlight. But the main task of the device is to charge phones, smartphones, tablets and other devices.

More about capacity

If you choose a portable charger for your mobile phone, then be sure to pay attention to the number of “swings” (mAh) or milliampere-hours. It is in them that the capacity is indicated and how much your smartphone is charged depends on this indicator.

Attention: the larger the capacity of the Power Bank, the greater its weight and dimensions. You don’t need to buy overly powerful devices for your smartphone if you only need to recharge your phone occasionally – it will be an unreasonable waste of money, and it will be inconvenient to carry a huge and heavy device.

Inside the Power Bank there are modern lithium-polymer or lithium-ion batteries, the main advantage of which is the minimum self-discharge current and high specific energy intensity. They can withstand up to 500-600 charge / discharge cycles, after which they slowly begin to degrade. On average, when you charge your phone 2-3 times a week, they last for 5-6 years, which is quite a decent period for modern batteries.

Now let’s figure out how to choose the right container. At the moment, there are devices on sale with a capacity of 2 to 20mAh. Find out how much battery capacity is on your phone. Add 20% to this and you get the desired capacity.

Example: Your smartphone has a 2200mAh battery. To fully charge, you need to use a Power Bank with a capacity of 2200 + 2200 * 0.2 = 2640. That is, theoretically, a bank with a capacity of Mach 2.5 is enough for a full charge, but it is better to play it safe and take 3.

Tablets have more capacious batteries, so devices with a capacity of 7-15 mah are suitable for them.

We calculate the number of charging cycles

Consider one subtlety of portable phone chargers that you must know without fail and take into account before choosing. Many people believe that if the battery capacity is 3mAh, then by purchasing a charger for 15 it will be possible to charge the phone 5 times. But this is a deep misconception. If you choose a bank that can charge the battery several times, then carefully read the following information.

Batteries have self-discharge. If you charge the 15 flywheel device to 100%, then after two days its capacity will be 14, after another 2 days – 11, etc. Different devices have different degrees of self-discharge, but it is present everywhere.

Power Bank is not 100% efficient. So, the battery has an output voltage of 3.7-3.5 volts (depending on the state of charge), while USB requires 5 volts. Therefore, a step-up transformer is included in the bank’s circuit, which also eats up part of the capacity. It is noteworthy that in the phone, these 5 volts are converted to 3.7 volts again, and the loss occurs again.

On average, the bank is able to give 70-80% of its real capacity when charging. And if in the city these losses are insignificant (by “feeding” the phone from Power Bank, you can get to a full charge), then for travelers it can become a problem. Therefore, be sure to purchase devices with a margin of 20 or even 30 percent to get the desired values.

Example: if the capacity of your battery in a smartphone is 2200mAh and you plan to charge it from the bank at least 5 times, then 2200 * 5 = 11000 + 11000 * 0.3 = 14300. The Mach 15,000 capacity will be enough to charge the device the required number of times until the batteries inside begin to degrade.

How to choose the right one

Now you know what a portable phone charger is called, how to correctly calculate capacity and stock. Let’s analyze which device is right for your phone.

The key tip is to decide in what format and when you need to recharge. If you use a phone for work and in 99% of 100 cases it is enough for the whole day, and you charge it every night, then a small 1mAh key fob that can be carried on keys is enough for you. It will not overload your pocket or get in the way, and this capacity is enough to charge your phone by 30-40 percent and safely get to the classic charging.

Considering small pocket phone chargers, you should focus on the batteries built into the cases. These are quite interesting devices, the main advantage of which is their compact size. You just purchase a convenient protective case for your phone and along with it you get an additional 2-3 thousand mAh battery that can fully charge your smartphone if necessary.

Charge currents

Native phone chargers have such a parameter as charging current. It can vary from 0.5 to 1.5 Amperes (sometimes even 2 A). The higher the current, the faster the battery will charge. For pocket chargers, this parameter is lower than for wired chargers, and usually amounts to 0.2-1 A. When choosing a device, remember that the higher the charging current, the sooner the device will charge. Do not buy inexpensive devices with minimal performance – very often they only provide maintenance of the battery charge, while not really charging the phone (during operation, the smartphone consumes as much or even more than a weak Power Bank gives it). Buy devices with a power of more than 0.5 A, and preferably 1 A, then your phone will be charged in 3 hours instead of 5.

Li-Ion devices

The most common types of charging are those powered by 18650 lithium-ion batteries. They are similar to conventional AA batteries, but are larger. Output voltage – 3.7 volts, standard capacity 2500 mAh, weight – 45 grams. Li-Ion batteries can withstand up to 600 charges without degradation, and by 1000 charge cycles they lose 20% of their capacity. The main advantage of the cells on lithium-ion devices is their long service life, low self-discharge current, low weight and no memory effect.

Of the minuses, one can single out a violation of the tightness of the batteries, which manifests itself when the device overheats – do not leave it on the battery, in the sun under the glass of a car, in other places with high temperatures. Overheating does not occur when charging on modern high-quality devices – special protection is installed in the unit.

Attention: today on the market there are a lot of fakes from unscrupulous manufacturers promising 30,000-50,000 mAh in inexpensive devices. Buy only branded Power Banks in trusted locations.

Note the approximate dependence of the capacity on the mass – 5,000 swings weighs at least 100 grams. Therefore, a 50,000 device will weigh a kilogram, and not 300 grams, as promised in various online stores. However, such a system for determining the real capacity is not a panacea – the Chinese have learned to put weighting agents in the case in order to convince buyers of the reality of the characteristics. You can check the capacity using a multimeter or calculations.

Li-Polymer devices

Lithium polymer batteries are considered to be more advanced devices than lithium-ion batteries. A special polymer with gel lithium acts as an electrolyte in them. They are rectangular plastic bags with two leads. The package contains electrolyte and working elements. The case of the Power Bank reliably protects an unstable battery from damage. The key advantages are low weight, high energy density per unit volume, and no memory effect. Of the minuses – a complex circuit that protects the battery from overheating, providing a specialized charging mode for current. Also, the battery should not be deeply discharged, since it may not turn on (it will be necessary to apply voltage directly to the contacts, bypassing the circuit in order to revive it).

Caution: Purchase only certified lithium polymer devices, as counterfeits often fail. They are prone to fire, generating enormous amounts of heat and gas, which is extremely harmful to health.

It is from these batteries that fires start and phones burn out. If a short circuit occurs while charging, the device could cause a serious fire.


If you want to be always in touch or your phone plays an important role in your life, then a portable charger should definitely be present in your pocket. The main thing is to decide on its capacity and weight. For travelers who spend a week without an outlet, powerful batteries for 15-30 thousand swings are suitable, for office workers small 1-3 thousandth batteries. We recommend that you purchase original chargers so as not to be disappointed in them – today there are a lot of fakes on the market. A quality item will not be cheap. The average price of an original can is $ 30-40.

If you have a phone and a tablet, then you can purchase a device with two outputs – it can charge them at the same time. There are many options on the market – research them before making your final choice.