FeaturesAble to charge two batteries20Ah PWMCan connect a solar panel up to 300WProtects the batteries from over charging and reverse feed132 x 70 x 25mmThis advanced solar PV Logic 20Ah 12V / 24V Twin Battery Charge Controller is designed to protect dual batteries from being overcharged by a solar panel/s up to 300w. Able to take a 12v or 24v solar input the energy from the solar panel will always be focused on the battery connected to the number 1 terminals until that battery is 70% charged. Then if a second battery is connected both will receive a simultaneous charge. This is idea in a motorhome of boat where its typical to have both a leisure battery and a starter battery. If only one battery is connected this will be charged until full.