Solar Charge controllers, with different model. the normal is PWM solar charge controller and MPPT solar charge controller.
MPPT solar charge controller: MPPT Maximum power point tracking Function , and short for MPPT. it compares with the PWM.
This solar charge controller could math the Lithium battery, Gel battery, and Flood Battery, Lead-Acid, lithium , also the LiFePO4 battery.
The battery voltage could start from 12V /24V /36V /48V /60V, also, you can connect 4 gel batteries of 12 volts which are set to 14.5 / 15 volts I have to set to 71 volts.
And the charge current from 30A 40A 50A 60A and 100A.
The solar panel 18V Solar Panel for 12V battery, 36V solar Panle for 24V <40V, 54V Solar Panel for 36V battery and 72V Solar Panle for 48V <80V, 60V battery is charged with 90V solar panel, voltage is less than 100V.