Power Bank – from the English. “Power bank, energy bank” – external portable battery, also called. Power Bank is also called ROM – Portable Charger or simply “external charger”. Having received a predetermined amount of electric charge from the network, the Power Bank is able to charge any compatible equipment independently and autonomously via a USB cable or Lightning in the case of Apple equipment. Power banks have a light weight and compact size, which makes it easy to take the device with you to places where it is impossible to connect to the mains.
Power Bank – Separation by Battery Type
- Li-ion batteries Li-Ion. The most popular Li-Ion battery used in ROM is 18650 (168A).
Those. parameters: capacity = 2500 mAh; number of recharge cycles = 500-1000; weight of 1 battery = 45 ± 5g.
The shape of the 1st battery is an AA battery, but a little larger.
- Lithium polymer batteries Li-Polimer – the electrolyte uses a polymer material with a low weight and the energy density per unit area is higher than that of Li-Ion.
How to choose a power bank?
Before you start choosing, you need to determine for yourself: how often in your daily life there is a need to recharge your gadgets autonomously? In other words: do you need a Power Bank, will it make your life easier?
The options can be different, for example:
- by the nature of your activity, you need to show videos, take photos, give presentations on your tablet to potential clients several times a day. To be constantly in touch is a necessity for you;
- the daily journey to the place of study or work takes more than 1-2 hours by public transport and you are not used to wasting this time;
- you love outdoor activities, travel to places far from civilization.
Having decided on the need for a device, proceed with the selection of a suitable model.
STEP 1: compatibility with other gadgets
Thanks to various cables and adapters, Power Bank is compatible with all modern digital devices: phones (iPhone and Android smartphones), tablets, MP3 and MP4 players, photo and video cameras and other energy-consuming gadgets. Their power parameters are identical.
You need to know the input voltage for your device that you are going to charge autonomously. USB specification is 5V DC (5V DC).
Power consumption may differ (1A or 2A). You can connect a smartphone or other gadget that needs a current of 1A to a 2A connector without any problems, the device will not take more than it needs.
The opposite situation: it is not recommended to connect, for example, a 2A tablet to the output of an external battery 1A. Charging will either take a very long time, or there will not be enough power to charge at all, which is bad for the device’s battery. First of all, such situations occur when charging iPads.
STEP 2: ROM capacity
You can follow the principle – “the more, the better”, but one must clearly understand that a Power Bank with a large volume weighs more and its own charging will take longer.
In order to correctly calculate the capacity of the external battery you need, you need to know which devices will have to be charged in terms of capacity and how many times you will need to do this away from the network.
How to correctly calculate how many full charges of your device the volume of the Power Bank will last?
There are objective reasons for the discrepancy between the declared and real capacity:
- own efficiency of the external battery ≈ 78.7 to 94.3%, the difference is the expected losses, conversion of electrical energy into heat;
- any device needs more energy for charging than the energy of their battery – by 29.2 – 43.1%;
- each device is equipped with its own controller that regulates charging, and each such voltage correction is a loss;
- if the phone put on charging is not turned off, then it spends the received energy for its own needs during the charging process, and the process can take ~ 2 hours.
Not an objective reason for the discrepancy between the promised capacity of the external battery and the real one is the indication of overestimated indicators in the technical documentation or on the ROM itself. This is practiced by little-known selling companies or “no name”.
In order to get the correct result and calculate how many times the gadget can be charged from the Power Bank, you need to multiply the capacity of the gadget’s batteries by 1.5 and divide the capacity of the ROM batteries by the resulting number.
STEP 3: power bank manufacturers
The number of global Power Bank manufacturers is growing from year to year. Among the many companies of various sizes, the TOP-10 stands out, which have proven themselves well in the market: PINENG, XIAOMI, DOCA, Lenovo, Sony, Yoobao, Samsung, Huawei, Asus, Momax.
In terms of sales volume in the world, the first place is occupied by PINENG (China), which received the status of the best Asian power bank manufacturer at the end of 2012.
XIAOMI (China), which produces its products under the Mi brand, is the third company in the world for the production of smartphones. XIAOMI is so widespread and famous that manufacturers have become victims of counterfeiting.
For the purchase of Power Bank from Sony, however, as well as for all the equipment of this brand, you will have to pay significantly more.
You can choose a cheap, non-branded Power Bank, the so-called “no name” (nameless), but, in most cases, their quality leaves much to be desired. Devices can be mounted from low-capacity batteries and from “left-wing” manufacturers.
The circumstances of the purchase are different, but such an acquisition may, unfortunately, not only fail to charge, but also spoil the charged expensive equipment.
STEP 4: additional functions of external charging
Additional options are optional, but increase the variety of ROM uses:
- LED flashlight, which can be additionally equipped with a reflector. Switching on / off – using a double tap on the control button, the brightness of the glow is different and does not depend on the capacity of the battery.
- Digital indication of charge. The LCD display with digital readout will show the percentage of charge for each USB port.
STEP 5: weight, dimensions and design of the portable battery
Most importantly, always keep in mind that as the capacity increases, the dimensions and weight of the device also increase.
The design can be completely different, it all depends on your taste, needs and the required capacity of the device.
Recommendations for the operation of power banks
An external battery will last longer if you follow a few simple rules:
- charge the ROM using serviceable chargers with the required characteristics;
- frequent use – for the benefit of the gadget, the manufacturers’ warranty obligations start at 500 cycles, which is enough for 5-6 years of intensive use;
- first ROM charge = 100%, do 3-4 full charge / discharge cycles to reach the maximum capacity of the device. If the discharge time of the external battery decreases, it is recommended to repeat the procedure from 3-4 cycles (the battery statistics will be overwritten);
- keep a fully charged / discharged PowerBank – to shorten its service life; if the device is not needed for a long time, leave ~ 1⁄2 charge in it.