:I have a General Electric Model 6RS934A2 Battery Vitalizer, I was told it is to charge 6V (pre-1960 era) car batteries. Mine puts out 9.4VAC, since it is missing its cigar lighter adapter which apparently had a diode.

Correction: I have a General Electric Model 6RS934A2 Battery Vitalizer, I was told it is to charge 6V (pre-1960 era) car batteries. Mine puts out 9.4VAC when unloaded; when connected to a battery it provides half-wave rectification. It has a resistor and lamp which draw current from the battery the rest of the time. One theory is this is for increasing the cold-cranking amperage, see "http://www.fieldlines.com/story/2006/6/11/360/48625"

:Correction: I have a General Electric Model 6RS934A2 Battery Vitalizer, I was told it is to charge 6V (pre-1960 era) car batteries. Mine puts out 9.4VAC when unloaded; when connected to a battery it provides half-wave rectification. It has a resistor and lamp which draw current from the battery the rest of the time. One theory is this is for increasing the cold-cranking amperage, see "http://www.fieldlines.com/story/2006/6/11/360/48625"

Mark:
Guessing: The lamp is maybe a Tungar rectifier bulb, and the resistor is to drop 115 to the filament and battery Voltage??
It plugs into the cigarette lighter and is a trickle charger???
Lewis