What Is The Real Output Capacity Of A Power Bank and How To Calculate It?

Here’s some food for thought.

When you’re shopping for or using a power bank to charge your phone, laptop, or whatever other device you have, how do you know you’re using a power bank that offers the proper power levels?

There are a lot of stats that come with your typical power bank. This one has 10,000mAh, while this one delivers 40Wh with a discharge efficiency of 75%. 

It can get very confusing very quickly, but fortunately, there’s a quick and easy way to figure out how good a power bank is, what its actual output capacity is, and whether it’s right for you.

Let’s get into it.

So Many People Get It Wrong

The way so many people believe power banks work is like this.

If it takes 2000mAh (mAh stands for milliampere per hour) to charge your smartphone, then it would make sense that a 10,000mAh power bank would charge that phone five times… right?

Well, not exactly.

The reality is that a 10,000mAh only refers to the power bank’s internal battery. As an example, this could refer to four 3.7V 2,500mAh batteries that you could find inside the power bank.

However, if the USB port of the charger is a standard 5V connection, this means the 3.7V charge from the batteries is being converted into a 5V charge that’s compatible with your devices, and therefore we need to convert the 10,000mAh as well.

In this case, a 10,000mAh power bank, the formula would look like this;

3.7V x 10,000 / 5V = 7,400 mAh

This means the output of a 10,000mAh power bank is actually only 7,400mAh, because of the conversion at the 5V USB connection!

You could also take into account conversion loss, which is the energy lost via the heat generated while the power bank is in use (which sits anywhere between 2% and 10%, depending on the brand), but the fact of the matter is that your power banks may not be running to the level you think they are.

You may be wondering if or why this is allowed.

Well, the fact of the matter is that most people don’t really understand how power banks work and therefore don’t need to describe it. 

Technically, a 10,000mAh power bank is just that; it’s just not the result you’re given when actually charging.

Nevertheless, once you understand how this works, you can start shopping smarter.

For example, here at Veger, we know power loss via incorrect formulas can be irritating at best. But, loss of power through energy transformation is unavoidable, so we aim to design power banks that break the mold.

The New Age of Power Bank

Take our S11 10,000mAh Fast Charging Mini Power Bank.

The Type C USB power supports PD and QC3.0 fast charging with speeds of up to 20W. It can even charge two devices simultaneously at 5V, even at 10,000mAh.

Or take the Tank Lite, a massive 50,000mAh with Fast Charging capabilities. With a maximum speed of 22.5W, you can charge the latest model iPhone 13 from 0% to 60% battery in just 30 minutes, and you can charge four of these devices simultaneously.

With every power bank loaded up with intelligent safeguards that protect from overcurrent, over-voltage, or overheating issues and affordable price tags, ensuring you’re using a quality power bank for a quality charge has never been easier.

Check out our catalog today and find the right power bank for you.