My Battery lay out is as follows: 2 Batteries on Port side, 2 Batteries on Starboard side and 1 Battery for Generator. Without thinking things through and getting a discount...I replaced the 2 old wet cell port Batteries with 2 AGM's. The 2 wet cell Batteries on the starboard side are only about 16 months old and are good so i did not replace them. While on a recent cruise I noticed the Helm Amp gauges were reading different charging rates, one read 12 amps and the other 14 amps. Also while anchoring out my fridge would quit running on the 12 volt system after a couple hours. My questions are: Should I go ahead and replace the good wet cells with the AGM's so they all match or does it make any difference? Should one of the Batteries on each side be a cranking Battery and one a deep cycle Battery. Does the 12 volt house system draw from both Port and Starboard battery banks.