I am thinking 160 watts should run the Ice box, well it does now.
My first though was the over head of the solar regulator is now like 2 volt of 24 volt where before it was like 2 volt out of 4 volt. (20v panel-14.2v battery-2v over head = 4 v to turn into extra power)
then I was thinking maybe you had a bad blocking diode in one of the panel that was draining the battery at night. with the new wiring you have 2 blocking diodes I would have though the solar regulator would guard against this discharge at night.

Thanks for posting this, something to think about.