What Is A Power Bank — Everything You Need to Know

6 min readSep 11, 2020

As many will agree, smartphones are one of the most essential devices in our lives, and we struggle to live without one in today’s hectic world. We may forget to grab our keys, but heading out without a phone is nigh-on impossible. With the amount of time we spend using our phones, the battery runs down, leaving us helpless. Since plugging in the phone to charge isn’t always feasible, we need a portable option to take with us when traveling or just dealing with our usual busy schedules.

The answer for many is a power bank. A is a portable charger that can store energy and release it to recharge other devices. However, to truly understand what a power bank is, you also need to know the technology.

How Does A Power Bank Work?

A power bank’s built-in battery charges through an external power supply, such as a wall socket, then stores the energy in chemical form. When needed, the battery sends electrical energy to the connected device via the output port.

The process consists of three parts: energy absorbing, storing and releasing. It works similarly to a cell phone battery, although a power bank can be more complex and have more functions depending on its design.

How Does A Power Bank Store Electrical Energy?

We can either charge up our devices through a mains power supply or battery. The two main types of batteries used in power banks are Lithium-ion and Lithium-polymer, which have the highest energy density, yet they are the lightest and smallest. Their charging and energy-releasing efficiency are also considerably high, making both Lithium-ion and Lithium-polymer batteries prone to spontaneous combustion.

Reliable power banks have built-in safety features, such as overloading protection and safeguards against excessive current, overheating, and overcharging.

What are the Different Types of Power Banks?

Power banks vary in sizes, shapes, as well as the ways they charge or release energy.

The power bank size tends to be the most important criterion; the bigger the power bank, the higher the charging capacity (measured in mAh). More capacity means more energy but also more weight.

Small-sized power banks (20,000mAh or below):

If you simply want a power bank to charge cell phones, 20,000mAh or below will do the job. The average battery capacity of recent cell phones is between 4,000 to 5,000mAh.

Anker powerhouse 120,000mAh

Although there are supposed 100,000mAh power banks on the market, their legitimacy is arguable. Larger ‘power banks’ range from between 40,000–60,000mAh and can be used to charge laptops, mini-fridges, and similar appliances and typically marketed towards campers. As you can imagine, those ‘power banks’ are usually the size of a car battery or bigger, clearly running counter to the purpose of a ‘portable’ power bank.

After size, the next important consideration is how a power bank charges and releases energy.

Standard USB power banks:

The most common power bank works just like a USB charger. They charge using a USB charger or a built-in plug, and then they become the USB charger to recharge a device via a USB cable.

Wireless power banks need to be charged through a USB cable, but they charge cell phones wirelessly, making the process more convenient. Unlike USB power banks that are restricted by cable type, wireless power banks can be used universally by all cellphones.

How Many Times Can A Power Bank Charge My Phone?

This depends on the capacity of the power bank and your mobile.

For example, the iPhone 11 battery has a 3,110mAh capacity. If the battery is flat and you charge it with a full 7,000mAh power bank, the power bank can charge the iPhone three times with 780mAh (7,000–3110*2=780mAh) remaining.

Well, this is only partially true. The general rule is that your power bank’s real capacity is around 2/3 of the theoretical capacity. A 10,00mAh power bank may only be around 6600mAh.

Are Power Banks Allowed on Planes?

Power banks are only allowed in carry-on luggage and should not exceed 100 watt-hours (Wh) per battery, around 26,315mAh. You will need to seek approval from the airline if your power bank exceeds 100Wh, inevitably prolonging the check-in process.

How to Extend your Power Bank’s Life?

In a similar way to cell phone batteries, power banks have an average of 300–500 charge-discharge cycles. When a power bank uses up all its cycles, it needs to be thrown away, so ensuring you purchase a reliable, high capacity power bank will elongate its charging life.

Your power bank’s life is also affected by how you use it. To make your power bank last a little longer, follow the following tips:

Charge your power bank when you’re not using it:

Lithium-ion and Lithium-polymer batteries age whether you use them or not, but they do age slower with some charge in them. If you plan on storing it away, charge it first to about 50%. A flat battery loses its charge at a faster rate than a charged battery.

Don’t fully charge the power bank:

The battery is most efficient when kept between 20% to 80%. Batteries don’t function well at either 100% or 0%, especially not for long periods.

Don’t expose it to extreme temperatures:

Batteries work best at temperatures between 5 and 25 degrees. In extreme scenarios, the battery inside a power bank will lose its energy faster and may even pose safety risks.

Don’t drop your power bank:

Just like your cell phone, your power bank also contains a circuit board, battery, and other components, so handle it with care.

How to Pick the Perfect Power Bank for Charging on the go?

The most significant advantage of wireless power banks is that it cuts the cord. You can also use one wireless power bank to charge different phones without being limited by the charging port and cable.

However, the most frustrating aspect is that they limit your movement. Most standard wireless charging pads require you to place your phone very precisely to charge. Placing your device incorrectly results in sporadic, inefficient charging.

Yet there’s a silver lining: incorporating wireless charging power banks with magnetic functionality.

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