I decided to move my batteries off of the firewall and into the well of the forward baggage compartment. This removes items from the firewall(a goal of mine), it'll help a little to move CG back as well as helping the batteries live longer(less harsh environment). I plan to put a hinged lid above the batteries. In addition to the batteries the compartment will house the bus manager and other electronics.
I'm using dual Earth X ETX680C batteries. I purchased the boxes from them as tehy are lightweight and fit like a glove.