Intially, on my last boat, I used a regulator, with similar capacity for two
56 watt panels into a small house battery bank. However, when I installed
the same panels on my present boat with a much larger bank (~800 AH), I
found I didn't even need the regulator since there was little risk that the
panels alone could ever bring the batteries to a full charge. What with the
demands of the boats normal loads. Full charge is normally only achieved
after several days of good wind for the wind generator or while running the
engine.

In my experience, any device, be it blocking diode or regulator will drop
the net voltage about a half amp per device. With solar panels this half
volt of the regulator can make a big difference when the sun angle is low
and the panel voltage is near that of the battery bank. Blocking diodes
remain necassary unless you do a manual disconnect when ever there isn't
enough sun to charge.

My experience and opinion, FWIW.

Steve
s/v Good Intentions