6 volt /12 volt

I believe that in order to have galvanic corrosion, a necessary ingredient is moisture. Place any two dissimilar metals in a glass of water and there will be a minute voltage produced. Sometimes, putting certain types of metal in your mouth will cause the fillings in your teeth to tingle. In a battery cable connection, the moisture is provided by the condensing acid vapors emitted through the vent caps on top of the battery. To counteract this condition, battery polarity was changed. This worked okay until the vehicle was parked and there was no load on the battery, then galvanic action took over again. Further actions to reduce corrosion where sealed top batteries and side post terminals, that's why you seldom see corrosion at the terminals any more. Smarter people than me are invited to dispute this, but that's my story and I'm stickin to it.

Edited February 18, 2015 by Larry W (see edit history)

Positive or negative ground does not make any difference for corrosion. Electrons do not really care which way they are going in the wire.

The issue on corrosion is dis-similar metals. The easiest one to think about is aluminum and steel connected together when you add salt enhanced water.(Think winter road slush from salting)

The poorer the connections, the quicker the corrosion. Even with same metals look at the corrosion that happens on battery connections.

Many manufacturers would like to go from copper to aluminum battery cables because of weight & cost savings, but the corrosion issues are very difficult to manage.

Al, For all I know, the powers that be may have just flipped a coin and it came up negitive.

. This may be the general consensus, as I consulted a retired automotive engineer and here's what he had to say. "Larry, in truth there is no "good" official reason, but old (early) engineers had some theories, and I will tell you the few I know. The spark plugs would last longer because the center electrode would run cooler. Another old theory was that the batteries would last longer because they thought that batteries were discharged when the vehicle body would make contact with a wet bush, or the wire wheels immersed in water or snow. Another reason yet, is that some of them theorized that the battery terminal corrosion will be less if connected positive to ground. Apparently none of the above reason were very valid and then they went back to negative to ground. I say went back because the very, very early model "T" started with negative to ground,. Hope that this helps somehow. At any rate this will make for good discussion over coffee."

I read somewhere years ago that ignition points lasted longer with positive ground.

I'll throw another little bone of contention into the 24 volt part of the discussion. In the 1960's John Deere sold it's tractors with multiple batteries wired in series rather than parallel to turn 24 volt starters. Somewhere in the text books of theory this was supposed to make the large diesel motors start better. In reality, what happened was you doubled (or quadrupled) the number of connections between the batteries and the starter, and in dusty wet conditions, created the potential for more trouble. I had two tractors with this system, a 4020 that used 2 12 volt batteries, and a 5020 that used 4 sixes. Both tractors were converted to 12 volt starters with a single large 12 volt battery, short fat cables and they have never started better. Despite having modified my systems, in a round about way this puts me in the keep it 6 volts and make proper connections camp for a stock car. Unless you are adding a modern power train, AC, stereos I don't see the need to mess with it. Keep things simple.

I don't see the need to mess with it. Keep things simple.

I agree