If you plan to buy a power bank make sure to take the following points into account. Generally, power banks are made of Lithium–ion or Lithium-polymer materials. You can be sure that these material will store electric energy in a most efficient way. Power banks can’t transfer all the energy to your mobile device, so it is always good to calculate a 10% loss of energy when you decide about the capacity of your future power bank. Buying a power bank which has a 80-90% rating is recommended. There are also some other important things which have to be considered when you are buying a power banks. These are: • Capacity • Number of output ports • Output specifications • Digital displays • Charging cycle Paying attention to the charging cycle is essential since it tells you how many time s you can completely charge and recharge the power bank and how long it is able to keep the power when it is not used. As you can see, all the things we have mentioned above have to be taken into consideration before you make the purchase. With a good quality power bank you will feel much better when you come in a situation to use it. Visit best-power-banks.com for more details.