The amount of charging that a device requires depends on the type and rating of batteries in use with the device. Some devices can withstand a constant sustained charging source and are not damaged or impaired should that charging source remain in place even after the batteries have been fully charged. Other devices will cut off the current to the batteries once they reach full charge. Some chargers employ a trickle charge, supplying only a small amount of current that can take several hours to charge a battery, whilst others can charge batteries in under an hour.
There are many different types of battery chargers available which employ many different methods, and we will only mention one or two as we concentrate on chargers employed for mobile phones, Smartphones, iPhones, iPods and iPads, which we often refer to as a portable battery charger.
One type of charger of note is the induction charger which uses a form of electromagnetic induction by transmitting electrical energy by means of some form of inductive coupling. For quite a number of years now they have been designed for use in environments where normal chargers may represent a risk of electrocution, such as bathrooms and other areas where the user may come into contact with water. Electric toothbrushes are a good example of objects that may use an induction charger. Powermat provide a range of induction mats designed to wirelessly charge a selection of smartphones, including the iPhone range.
Probably the biggest use for battery chargers is in the mobile phone market, and in recent years standards were developed for charging mobile devices using USB connections. The microUSB connector was developed specifically to connect a USB cable to a mobile device such as a phone or a digital camera. Voltages on USB connections are designed at or around 5 Volts with a maximum of 5.25 Volts, so they are ideal in most situations due to the low voltages involved. Since 2009 most of the major mobile phone vendors agreed to standardize the use of Micro-USB as the interface on mobile phones for the purpose of charging the batteries.
A popular type of charger is the in car battery charger for use with devices such as mobile phones, MP3 players and SatNav models. They receive their power via a connection with a car cigarette lighter and have an input range of somewhere between 12 and 24 Volts and output 5 Volts at 1 Amp current. Some of these chargers even come with a selection of connector tips to make them compatible with a range of popular mobile devices. A good example of a universal car charger is the Belkin F8Z689CW which is designed to charge your Apple device such as iPad, iPhone or iPod whilst on the move. This compact device sits neatly in your dashboard and connects to your cigarette lighter, providing a 3 foot cable for connection to your mobile device.
There are a wide variety of mobile battery chargers and adapters currently on the market specifically designed for use with mobile devices, and it really just depends on the model that suits your needs. I would certainly recommend buying a model from a well known manufacturer, particularly as a lot of cheaper copies have flooded the market in recent months, some of which have been found to be faulty, and in some cases dangerous.