I HAVE FITTED THE SOLAR PANEL BOUGHT FROM CHRIS. MY QUESTION IS WHEN CRUISING AND BATTERY CHARGING FROM ENGINE, DO I NEED TO DISCONECT THE SOLAR PANEL FROM BATTERY?
You shouldn't have to, if I remember correctly, they have diodes on them. this will stop current going to panel. you certainly won't if you have fitted a controller unit between the panel and the battery bank.
Yes, Steve is right, they have a built in diode so won't draw a current from the alternator or flatten the battery, the panels are fit and forget and designed to keep the batteries topped up, dependant on your battery size you shouldn't overcharge.