With the family car out of service for the duration, the September 1943 issue of Popular Mechanics offers this suggestion for putting the radio and battery to work by bringing the radio into the house.
Here, the set is mounted on a small shelf, with a speaker mounted above it. The six-volt car battery is in a carrier on the floor underneath, connected to an optional trickle charger. The antenna is mounted on a bracket on the wall. The ground wire is run to a metal plate which could be placed under a carpet or, on the ground floor, to a piece of sheet metal placed under the floor joists.
The magazine points out that the car radio probably provided good reception. If the project looks familiar, we previously carried a similar one for mounting the radio inside, and another for putting the radio on a bicycle.