You need an MPPT charge controller to reduce the voltage down to the right voltage,about 14V, to charge the battery, but also increase the current on the output. If you use a PWM charge controller, because watts (or power) equals volts times amps, if you drop the volts down to the right voltage for your battery bank, the volts are going to drop, the amps are going to say the same, and you’re going to lose about half of the power. With an MPPT charge controller, it will drop the volts, but raise the amps, so you’re going to get more of that power from that solar panel to your battery.