When we want to buy a solar charge controller,which factors we should consider.I think You should consider the following three factors.

       First,the solar panel power.For example,If you have a 150W solar panel,voltage 18 v,Its current is 8A,I suggest you should choose 10A solar controller,because you  have to have 20~30% current margin.

       Second,the solar panel voltage.The solar panel has two voltages,working voltage and short circuit voltage.For example,the solar panel of voltage 12V's working voltage is 18V and short circuit voltage is 21V.If the solar panel of voltage 24V's working voltage is 36V and short circuit is 42V.12V solar panel has to choose 12V solar charge controller.

       The last,using occasions .In general the solar charge controller is divided into solar street lamp controller and off-grid system controller.It is different function between them.Solar street lamp controller has light control and time control functions,off-grid system controlle has output 24 hours a day.