Pulse Width Modulated (PWM) charge controllers turn on and off very rapidly; holding the batteries fully charged and making better use of available power.
Maximum Power Point Tracking (MPPT) charge controllers would find the point in which the source can deliver power most efficiently, and then charge the batteries. MPPT charge controllers are normally used in larger arrays; they also allow the use of modules with higher rated voltage. MPPT cost more than other charge controllers but can deliver up to 30% more charging capacity from the solar panels to the battery bank.
Model: XW-MPPT60-150View product
Model: SS-MPPT-15LView product