Planning on adding a house battery (two Trojan T-105 6V) for electronics. Currently have 2520 with twin Suzuki 200's with two start batteries with two Perko style switches all located in the transom. I will get rid of the Perko style switches and switch over to appropriate BEP cluster (3 bank) as part of the upgrade. Wondering where people install the "third" house battery? Thinking about the starboard side V-berth compartment or maybe the forward bilge which would be a more central (less listing?) location? Might have to install new hatch for access to forward bilge area (haven't measured pie-hole diameter yet, 6V might fit through the pie hole?) and a platform for the batteries to sit on. Thoughts/recommendations much appreciated.