Batteries :
We have three batteries, two larger batteries, and one car size battery (starter battery); these are connected to a battery charger and a battery monitor / management device. The larger batteries will always be drained first, saving the started battery to start the engine when necessary. I believe I will always have enough power for refrigeration, although if I ever decide to turn the icebox which is located forward of my stove in to a freezer then I may need to do more research AND fabricate a much tighter lid ...
Vents / Louvers :
Being quite new to all this, and not being familiar, at all, with other Ericson's, I don't quite understand whey anyone would need install louvers on the face of all settees ? The configuration of the cabin must be quite different than ours. We have seating and table tops on both the Port and Starboard sides of the mast. The port side houses two storage areas and the holding tank, and the starboard side has two 15 gallon water tanks beneath the seat cushions with a table top that can be that can be dropped down and fitted between the two for a single sleeping area .
I would guess that the icebox and settee must be on the same side for the E38 you're speaking of ?