Power banks are commonplace and with our increasing use of battery powered equipment: everything from mobile phones to battery powered headphones, portable speakers, MP3 players can be charged via a power bank. They are effectively a portable charger. All they need is a USB charging interface.
Power banks come in a variety of shapes and sizes and to suit many different people and their needs.
Power banks can be defined as portable batteries that use circuitry to control any power in and power out. They can charged up using a USB charger when power is available, and then used to charge battery powered items like mobile phones and a host of other devices that would normally use a USB charger.
The name power bank can be likened to a financial bank where funds can be deposited, stored, and withdrawn when needed. These items are also often referred to as portable chargers, as they can charge items like mobile phones without the need to be connected to the mains during charging, although they will need to be charged, and this normally requires a mains charger.
There are a few different types of power bank portable charger that can be bought. Obviously the size is one of the main criteria, but there are some other categories that can be considered.
There are two main forms of lifetime that are associated with power banks.
A good power bank can hold charge for up to 6 months with only a small loss of charge, but lower quality ones may only retain a useful charge for about a month. These figures are for room temperature, but storing them outside these temperatures considerably reduces their performance.
All power banks use rechargeable batteries based around lithium technology. Lithium-Ion and Lithium-Polymer batteries are most commonly used for power banks but don’t be surprised if other types start to hit the market before long. Battery technology is key to many new developments: everything from mobile phones to electric vehicles, and as a result it is quite likely there will be some spin-offs into power banks.
The two technologies that are currently used have slightly different properties:
Both forms of power bank work well, but it is a balance between cost and performance.
Power bank portable chargers are particularly useful as they enable battery powered items to be charged on the go. As it is not always possible to reach a mains power point every time a mobile phone or other battery powered item needs charging, these power banks are have now become an established product and they are very useful, especially when travelling.
When looking at how a power bank works, it is essentially a battery into which power is passed typically from a mains powered USB charger. This is stored and then passed out to the device under charge as required.
To facilitate this operation, the power bank not only consists of a battery itself, but some sophisticated electronics which manages all of these operations.
Power bank battery technology
Whilst the management of the battery charging and discharging is key to the way the power bank works, so too is the battery technology employed.
Power banks are generally very easy to use, and typically conform to some simple conventions, especially with respect to the connectors. Normally power bank connectors have separate functions.
When using the power bank, it is normally only necessary to connect a powered USB micro connector to it for it to receive charge. Depending on the power bank capacity, its charge level, and the charger, the ambient temperature, etc., it can take quite a while to complete its charge. As an example, a 1500mAh rated power bank should take very roughly about the same time as a typical smartphone to charge. For larger power banks, this time can be considerably increased – it may take two three, four . . . times as long.
Power banks have electronic battery management and this includes a safety cut-off to prevent overcharging and overheating. However, whenever possible, it is best to remove the power bank from charger when it is full – at least avoid leaving it connected long-term after its full.
However when using the power bank to charge electronic devices, the leads need to be connected, and it is normally necessary to use a button on the power bank to enable the charging. This is required because a sort circuit on the output of the power bank could generate a lot of heat and possibly cause the power bank to catch fire or explode. The prevent keys in pockets and other metallic items causing an accidental short circuit, the output normally has to be enabled before use.
Often the power bank will have a simple LED indicator showing the level of charge it has when charging is enabled, or when it is being charged. These indicators often turn off after a short while to preserve the power bank charge.Tags: definition, technology, types