If you had a 1200ah bank draining to the point where you had to start an engine to charge it in less than a day I have to wonder what kind of washer/dryer electric stove and air conditioner you were running.
That you had two banks that size leaves me speechless. The weight alone (24 type 31's, or 8d's), just wow.
Obviously you would have to have a inboard diesel to charge that 1200ah , the 25% it's going to WANT at bulk charge would be 300 amps. Not your typical alternator set up.
You did / do know that batteries need to have that 25% of capacity for bulk rate charge right?
Unless you are waving a couple hundred square feet of solar you can't be meeting the need of that sized bank.
No way you are doing that on solar that fits on a boat
We're talking a couple hundred ah of batteries and portable generators
, not 9kw Northern Lights that can throw out a couple hundred amps.
Like I said, my 300w makes 9ah, more than I'm using even when sailing and running my instruments and autopilot.