{"id":5281,"date":"2021-09-27T23:00:17","date_gmt":"2021-09-27T21:00:17","guid":{"rendered":"https:\/\/powerbank20.com\/?page_id=5281"},"modified":"2023-08-29T20:59:46","modified_gmt":"2023-08-29T18:59:46","slug":"actual-output-capacity","status":"publish","type":"page","link":"https:\/\/powerbank20.com\/en\/actual-output-capacity\/","title":{"rendered":"What is the real output capacity of a Power bank?"},"content":{"rendered":"

Do you know how many times you can recharge your cell phone with a 10000mAh or a 20000mAh power bank?<\/p>\n

A very common mistake among those of us who want to know the number of charges we can get on our devices with a power bank<\/a><\/strong> is to divide the capacities of both devices, i.e.:<\/p>\n

Number of Charges = Power Bank Capacity (mAh) \/ Smartphone Capacity (mAh)<\/strong><\/p>\n

For example, if you have a smartphone with a 2500mAh battery capacity and you want to buy a 10000mAh<\/a> power bank, how many charges could you get?<\/p>\n

If we apply the above formula we get 4 full charges:<\/p>\n

Number of Charges<\/strong> = 10000 mAh \/ 2500 mAh = 4 charges<\/strong><\/p>\n

THAT\u2019S A BIG MISTAKE!!<\/strong><\/span><\/p>\n

We are sorry to tell you that this calculation would be incorrect because the 10000mAh of the power bank refers to the capacity of its internal battery.<\/span><\/p>\n

A result closer to reality would be to use the actual capacity available at the output USB port of the power bank:<\/span><\/p>\n

Number of Charges = Actual Power Bank Capacity \/ Smartphone Capacity<\/strong><\/p>\n

If we assume that the actual capacity is 6000 mAh we would have enough juice for 2 full charges of our smartphone:<\/p>\n

Number of Charges<\/strong> = 6000 mAh \/ 2400 mAh = 2,5 charges<\/strong><\/p>\n

Although this second formula is still technically incorrect (capacities divide at different voltages) we wanted to make you see in a simple way that the number of charges is much lower than expected despite the fact that the power bank is advertised with a capacity of 10000 mAh.<\/em><\/p>\n

And this is the main problem that many Amazon users encounter when buying a power bank:<\/p>\n

\"customerIn the following article, we are going to explain in depth how to calculate the actual capacity and the number of charges of a power bank in any device and for different charging voltages.<\/p>\n

Although the content of this article may be a bit technical and boring to read, we have tried to make it as easy to understand as possible for anyone without previous experience.<\/p>\n

After reading this article you will become a power bank expert!<\/p>\n\n

\ud83d\udc47OTHER GUIDES YOU SHOULD READ\ud83d\udc47<\/strong><\/p>\n

\n
\n
\"laptop<\/a>
Laptop Power bank \ud83d\udcbb<\/a><\/strong><\/figcaption><\/figure>\n<\/div><\/div>\n
\n
\"best<\/a>
Best portable solar chargers<\/a><\/strong><\/figcaption><\/figure>\n<\/div><\/div>\n
\n
\"power<\/a>
Can you bring portable chargers on a plane?<\/a><\/strong><\/figcaption><\/figure>\n<\/div><\/div>\n<\/div>\n

Which are the components of a Power bank?<\/h2>\n

First of all, you should get familiar with the 2 basic elements that make up a Power bank:<\/p>\n

    \n
  1. A rechargeable battery<\/strong> of a certain capacity (mAh) and nominal voltage (V).<\/li>\n
  2. An electronic circuit<\/strong> that controls the charging and discharging process of the rechargeable battery, as well as performing other important functions such as, for example, protection against over-voltage, over-discharge, temperature control, etc.<\/li>\n<\/ol>\n

    As we will see below, the actual output capacity of a power bank will depend on the quality of such components.<\/span><\/p>\n

    Battery capacity and voltage rating<\/h3>\n

    The battery of a power bank consists of lithium-ion (Li-Ion<\/strong>) or lithium polymer (LiPo<\/strong>) cells.<\/p>\n

    \"\"<\/p>\n

    Usually, they use cells with a nominal voltage of 3.7 volts (V)<\/strong> and a capacity ranging from 1500 to 5000 milliampere-hours (mAh)<\/strong>. However, cells with other voltages are also available on the market, e.g., 3.6V, 3.8V or 3.85V.<\/p>\n

    \"\"
    Lithium Ion Battery Cell 2400mAh 3.7V<\/figcaption><\/figure>\n

    Additionally, the battery may be made of a single cell or several cells connected together:<\/p>\n

    \n
    <\/span>One cell<\/strong><\/div>
    \n

    If the power bank battery is made of a single cell, its capacity and rated voltage will be the same as that of the cell itself.\"\"<\/p>\n<\/div><\/div>\n

    <\/span>Multiple cells<\/strong><\/div>
    \n

    If the power bank battery is made up of multiple cells<\/strong>, its capacity and voltage rating will depend on the individual capacity and voltage of each of the cells as well as the configuration used (series or parallel circuits<\/a>) to connect the cells together.<\/p>\n

    Generally, a power bank battery uses cells with the same capacity and voltage nominal connected in parallel.<\/p><\/blockquote>\n

    With a parallel connection, the voltage<\/strong> of the power bank battery is the same as the voltage of the cells and its capacity<\/strong> is the sum of the individual capacity of each of the connected cells.<\/p>\n

    \"\"<\/p>\n

    In the previous image, we see an example with 4 cells of lithium-ion (Li-Ion) of 3.6V and 3400mAh have been connected in parallel<\/strong> resulting in a battery with a capacity of 13600mAh and a voltage of 3.6V.<\/p>\n

    Therefore, if we wanted to make a power bank using 3400mAh and 3.6V cells connected in parallel, the battery will have a voltage of 3.6V and its capacity will depend on the number of cells used:<\/p>\n