When your batteries are lower the voltage from your solar will too.
Your batteries are a big resistor. The voltage may look like 16 volts
at the panel but at the battery you will see it at about 1 to 1.5 volts
about its charge so you don't have to worry about it. The thing that
really fries your batteries are those 3 stage balmar regulators that
push 100 or more amps into your batteries at high voltage.

You're only dealing with 5 amps per panel with solar and on a crazy
blow day maybe 15 if your lucky with your wind gen. I have had days
when 35 knots of blow and hot sun was making 25 amps and all I did was
turn on the stereo or TV and a light or two - instant regulator.

Remember back in the days of the 70's where you turned on your lights
to drive cross-county so you wouldn't over work your regulator? Maybe
your younger then I but it works the same today.

You're working so hard to make juice, the last thing you want to do
is ragulate it.