What Solar panel for my start batt ?

[yohoho]

Hi, I've just bought a Bosch N70 batt for starting. Specs are 135 RC, CCA 300, 90-100 AH. The engine is a 3 cylinder Perkins. I had the idea of putting a small solar panel running through a reg to give it a small permanent charge to keep it topped up. I've seen some of thse panels for this purpose for sale but they are extremely small around 1.5 or 4 watts. Will these be a waste of time on a battery as large as this ??

[scottyt]

i have one of the sunsea se-500 7.5 watt panels and it keeps my 230 mp hour house battery happy. it even brings it over a 2 weeks if my bank is not 100 %, ie i can go to the boat and mess around for a few hours with the lights one and a week later its back up to 100 %. in fact i would say put a reg on it for a smaller battery