Packard Forum Index » Post-War (1946-54)

If no 6 volt battery is available it is OK to start a 6 volt car on a 12 volt battery and run it for a few minutes.

Make sure the radio and other things are all turned off.Don't forget the dome lights.

No resistor is necessary as long as you limit your running time to 10 or 15 minutes.

I have had a coil overheat and quit after half an hour but once it cooled down it worked normally again. This was on a Dodge with Autolite ignition like a Packard.

Agreed, Rusty. I have worked on collections where the game of battery roulette necessitated the use of a 12V jump pack often, and we did just as you state no absolutely no ill effect. Caveat: if the eninge doesn't fire right away, don't keep cranking hoping for a miracle. I always keep a plastic squeeze bottle, the kind with a pointed tip (like diners use for ketchup, but clear plastic instead of red), before starting a dead horse take the air cleaner off, locate the bowl vent in the throat of the carb, place the pointed tip of the bottle in the vent tube and fill the fuel bowl through the tube, until it overflows slightly. Give a small shot down the throat and replace the air cleaner. This way you don't have to crank the starter excessively to pull fuel up from the tank, it should fire right away, providing everything else is in order. The fuel in the carb bowl should run the engine long enough to pull fuel from the tank and prine the system. More than two times at that and you have pump issues. Some add a supplimental electric pump to prime the carb, that's Ok too, as long as the mechanical pump can pull fuel through after starting.

One other note on this. The case I handled with a car stuck in a trailer on a hill I forgot to do something the manual says to do with a slow cranking motor - depress the clutch. It may have only been heavy transmission oil that was keeping the car from cranking. Oh well, the 12 volt battery I keep on the shelf is usually only 75% charged anyway.

Using a 12v battery to start a 6v car is like being married with a girlfriend on the side, sooner or later you're going to get caught. I would say either fix it so it starts properly on 6v, or convert it to 12v, I wouldn't try a half and half deal.

After saying that, when I converted my '48 to 12v, all I have to do now is let the fuel pump build up pressure for about 5 sec, pump the gas once, then bump the key. It starts that quickly EVERY time. No more of this crank, crank, crank, crank, crank, crank, crank, crank, crank, crank, crank, crank, crank, crank, sputter, crank, crank, crank, crank, crank, maybe sputter, fire. That gets old and tiring. It took almost a minute to start on 6v, now it's instant.

I just want to offer my recent experience with my 1950 Packard over the 6 months I have owned it. When I first got the car it acted like my 1934 Nash and my 1935 Diamond T when starting. It would crank very slowly, turn quite a few revolutions, and eventually fire. It had me concerned and starting to think about 8 volt batteries, 12 volt conversions, etc.

Since that time I havbe cleaned off the battery cable terminals, verified the cables are thick ones designed for 6 volts, ground the valves, replaced the rings, and replaced everything in the ignition from the coil to the head with new parts. Now I turn on the key, pump the accelerator lightly a few strokes (only when cold) and push down to engage the starter under the gas pedal. It cranks one or 2 revolutions and fires instantly just like my 12 volt cars! from this experience I think a six volt system can work just fine if everything is in top shape.

I've seen a car for sale with some kind of dual mode battery in it with 4 terminals. Supposedly, it used 12v for starting and the car ran off the other 2 terminals at 6v. I didn't buy the car so I can't say how well this worked.