Flat starting batteries can be dangerous things. This system has been designed to reduce the chance of running down your main starting battery (or another battery you may be worried about). When installed, the Add-A-Battery Mini isolates the start battery from the leisure loads which prevents the discharge of the start battery. The Add-A-Battery Mini offers a simple way to control the charging and battery switching of two battery banks. It is designed for boats with an alternator output of 65A or less. Please note the image shown for this product is not the mini, it is very similar and we will shortly update the correct picture.