I would not worry much about venting the second front seat battery
compartment. VW sold countless thousands of Vanagons with beds in them
and battery compartments without vents. Many also had tables inside.
Clearly these are meant to be slept in and camped in. Some of these even
had factory aux batteries.

IMO, the sealed from the inside and vented to the outside battery
compartment found in the VW Campers is a mickey-mouse hand done setup
installed only to comply with a requirement for some RV approval
sticker. The venting is appropriate for RVs fitted with chargers that
operate even while the vehicle is parked. Charging on those takes place
when people are sleeping inside or even when the vehicle is unattended.
The Westy charges only when the engine is running.

Mark

>..................................Also, there is no
>provision for a battery vent in the battery compartment under the drivers
>seat.I wanted to use my best battery for cranking, but cannot do this
>because no vent exists for the weaker battery.Does anybody know how long an
>auxillery battery will last ? Forever?
>
>
>