Battery Encyclopedia/The difference between charger and adapter

The difference between charger and adapter

Preface

In our business with most of users and customers, we found that charger and adapter are easy to be confused by user. They would think they are the same electric appliance. And it wastes time and causes troubles between both parties. So it is very necessary to clarify the differences between charger and adapter. 

About the charger

The charger is a device converting the alternating current into low voltage direct current. There is a control circuit in its internal which can meet the battery charging requirements, like current-limiting, voltage-limiting, etc. 

According to the differences of battery characteristics, the charging mode of charger is different. At present, it can be divided into two types. One is used to charge lead-acid battery, NI-MH battery, NI-CD battery, etc. This charger type is constant current charge. When the battery is charged to its highest limited voltage, charging is finished. The other charger type is for lithium battery. Its charging mode is CC-CV. First is constant current, and then is constant voltage. Here we will use the lithium battery with 3.7V nominal voltage as an example to make further explaination. If this 3.7V lithium battery needs a 4.2V/1A charger, its charging process must be this: firstly, use 1A contant current to charge the battery into 4.2V (in this process the voltage is variable, getting high little by little), and then, the charger will turn into constant voltage mode, use constant voltage 4.2V to continue to charge. In this process, the charging current is variable, and current is getting small, until the current reach to charger’s cut-off current, and the charger will stop charging. Under normal situation, the charger’s indicator light will be changed from red light (represent in charging) to green light (stop charging). 

About adapter

The power adapter we usually see on the market is the power converter without the process of voltage transformation, rectification and voltage stabilization. The output is direct current. In the situation of meeting the power, it can be understood as low-voltage and voltage stabilization power supply. It will be applied to telephone set, game machine, walkman, laptop, and other electric appliances.