Yogesh Sapkale 21 September 2015
How to select a power-bank that would save your day

With speedier processors and more RAM (random access memory), mobile handsets are becoming faster every day. Although the new-generation hardware consumes less power, the battery, which allows the show to go on, is not getting smarter. So, you will find smartphone users searching for a charging point all the time. There is another option too. Use a power-bank to recharge your mobile devices. This comes handy, especially if you travel a lot and do not have time and opportunity to recharge your mobile device.

A power-bank is a portable device that can supply power through USB (universal serial bus) using the stored energy of its built-in batteries. This is similar to an inverter we use at homes and offices as a backup for electricity disruptions. There are thousands of power-banks available in the market selling for a few bucks to some thousand rupees. So how can one choose a right power-bank?

First, check the capacity of the mobile battery, which is denoted in milliampere hour (mAh). So, if your device battery shows 2,300mAh, it means that it can hold that much energy charge. In this case, you need to buy a power-bank with minimum 2,300mAh so that it can provide at least one full recharge for your mobile device.

Second, check the battery output. It will be denoted on the battery in volts (V). Normally, it is below 5V or/and 2.0A. However, since most new mobile devices have adopted this as a standard, you need not worry too much about it even if your device shows numbers below this.

Now, an important question: How many times do you want to recharge your device/s? If you are planning to recharge a single device, you can either go for a power-bank that would give you one or two full recharges. If you want to recharge more than one device, you need to take the cumulative energy value (total of battery capacity) of these devices and choose accordingly. However, ensure that the power-bank has additional charging cable and connecting points for simultaneous charging of your devices.

Also, while deciding on the capacity of the power-bank, do consider the average health of the battery and conversion rate. Normally, both are considered at about 80% or 0.8 of the battery capacity. A simple formula thus would be:

Battery capacity/0.8 (average health)/0.8 (conversion rate) x n (the number of times you need to recharge the device).

From this example, 2,300mAh/ 0.8/0.8 x 2=7,200 (rounded off). So for a device with a battery capacity of 2,300mAh, you need to have a power-bank of about 7,200mAh capacity for two full recharges.

Which brand should one buy? This is a complicated question because, until recently, there were hardly any standard brands in power-banks available in India. Although these power-banks are available at a throwaway price, I would not recommend these for two simple reasons. One, the after sales support; and, second, the quality of the power-bank, including the battery itself. Remember, dubious batteries tend to heat a lot and may cause explosion, in rare cases.

While unbranded power-banks are available at cheap rates, known brands, like Sony, Samsung, Lenovo and Asus, command a higher price. The launch of power-bank from Mi has completely changed the scenario and several top brands are now selling power-banks at a reasonable price. For example, a 10,400mAh power-bank from Asus costs about Rs1,699 and Lenovo sells at around Rs2,297. At the same time, Mi sells the same capacity power-bank at just Rs999. Even Ambrane, PowerXcel also sell it at Rs999.

When you buy a branded power-bank, you get peace of mind and some additional features like metal casing, smart-control and charging-discharging chips as well as protection from overcharging and over-discharge. I can say from personal experience that Mi power-bank is one of the best for regular usage. It has ample power (10,400mAh) and comes with an aluminium casing and smart-chips. If you want to buy some other brand, check, if it has similar features.