Picking what controller is best suited for you will depend on your battery type, and other factors. If you need a controller for your PV system, then you have to make sure that it is rated properly for the battery voltage, as well as the current and voltage of your solar panel array.
PWM systems are generally rated for up to a maximum of 24V depending on the model, while the more advanced MPPT devices can handle up to 48V systems, which are becoming increasingly common.
Your devices will also likely have a rating for how many amps it can handle, with MPPT devices again having a higher capacity.
To calculate the amps of your solar array, simple run the numbers: Amps = Watts/Volts.
If you have a 1,600W solar array of four panels, rated for 24V. Then 1,600/24 gives you a potential for 66.67 amps, and you should ensure that the controller is rated for more than that, or it could overload.