I don't believe connecting the solar to the 12v or 144v battery bank will affect shading impacts directly. This is because solar gets up to voltage easily even in overcast weather, but the amps will be very low. According to a chart in a PV text I have, if only one cell in a module (modules often have over 30 cells) is completely shaded, the current at about 16 V will drop from 2.5 amps to less than 0.5 amps.
The book also makes the point that if there is one MPPT controller, which adjusts the voltage to maximize power output, that is connected to modules (panels) in different orientations, there is a lowest common denominator effect, so the panel with the least direct sun will drag down the rest. This should encourage us to wire panels independently, in parallel, which is not possible to get 144v since several panels would have to be wired in series to add their voltages up to 144v. So that's the reason to investigate step-up converters. You'll have to weigh their cost and (in)efficiency, but I don't think the many panels in a 144v array will ever completely avoid shade on a sailboat, it's hard for even one panel to do it!Thin film panels are more shade tolerant, so despite their inefficiency, are worth a look.
The 48v system I'm going to build in the spring will be easier, probably just two 24v panels in series, but this is a good problem solving/optimization exercise. Speaking of that, can some battery experts tell us if it's a bad idea to say, wire four 12v panels, in parallel, one to each battery in a 48v system? Maybe some batteries would be charged less than others? Then for power, you'd need a complicated switching system to connect the batteries in series? Can they be connected both ways if you have four charge controllers? (Or in Steve's case, six 24v controllers) I drew it out and it doesn't seem like there'd be any shorts or anything: wire it in series for the motor, then connect to smaller parts of it for each solar charger.Damon
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