We've been using 250 watts of solar for the last 5 years and I've found a few very interesting things.
Normally, the solar array (around 20 amps in full sunlight) has charged the batteries to the point of trickle charging for the rest of the day, by 11AM. It doesn't seem to matter how much we consume for the rest of the day, I'll not see any more 'bulk' charging. By the way, I do not have 12 volt refrigeration. So, by dusk we've been trickle charging all afternoon but not getting that last bit to get them all the way up. Night comes, the time when we're watching movies on the computer et al, and the consumption drains the house bank back down to 12.4 by dawn, and it all begins again.
This is of course the best case scenario. 4 days w/o good sunshine and I'd be in real trouble w/o the generator, if I didn't curtail usage hugely.
Of course at night La Luna doesn't help, so enter the windgen. The idea was to lessen the overnight drain. Funny thing, a windgen needs wind, just as the solar panels need the sun. Well, quite often the wind dies at night, even here in the Caribbean. Actually, this year the Christmas Winds still haven't arrived. Summer time, don't count on wind too much. Today, a ten hour 70 mile voyage in around 20 knots of wind produced 35 amps from the windgen. That's less than 2 hours of solar input, so don't expect too much from a windgen.
Of course, we are full time liveaboards with a bit of a electrical addiction, but still, I don't see how adding a huge bank of solar panels would improve this scenario very much if the panels are cutting back to a trickle charge by mid morning. You'd just get to that point faster.
Please Mr. Neptune, can I win the lotto next week so we can have lithium ion batteries?
Sounds like the dreaded premature floatulation,
a very common problem with far too many controllers, chargers etc... The lawyers try to make them "safe" and the absorption duration is often far too short, especially for a full time cruiser.
If your controller is adjustable/programable (some require an additional remote or a computer for this) raise the absorption voltage to the highest your batteries are rated for, eg: Trojan's would be set to 14.8V, then extend the absorption duration. Some controllers are set with as little as 1 hour of absorption time. This is far too short. You'll want more like 3-5+ hours depending upon usage & charge rate to bank ratio...
If you can't lengthen the absorption duration, simply increase the float voltage into the low 14's... If you're still at 12.4V by morning you're not doing horribly but by increasing the absorption voltage to the max your batteries can take AND extending the absorption duration
you can see a marked improvement and avoid premature floatulation...