[Althornin]

Originally posted by Since87
[b]No, it is you who is missing things.

It seems to me I've explained things such that anyone who is truly trying to understand can. However, I'll try briefly one more time.

the problem is you are wrong, AFAIK. You ignore one limit (ion concentration and salt bridge) to focus on the other ("leakage path").

Assume you have a D-cell battery.

If there is no conductor between the positive and negative terminals of the battery, then very little reaction will occur in the battery. There is no need to apply a voltage to the battery to stop the reaction from occuring.

thanks for the patronizing "lesson". I think i said the same thing about 15 posts ago.

If there is a copper wire connecting the two terminals of the battery, then a very energetic reaction will occur in the battery. In theory you could use an external power source to maintain the 'natural' voltage of the battery between the terminals. However, considering the amount of power that would need to be dissipated in the copper wire to maintain that 'natural' battery voltage, it's pointless to try.

Im sorry, but you are not correct here.
The output of the galvanic cell is limited by the ion concentration in the salt bridge, not only by the resistance of the connection between the two metals.
Ergo, you are incorrect wrt to power required.
I believe that i have been quite clear in saying this, yet you continue to ignore my statements. If you could direct your content to showing me the flaw in my thinking rather than repeating yourself, maybe we could move on.

You seem to be neglecting the electrolyte in your considerations (ion concentration...)
from your source:

Electrolyte factors that have a major influence on bimetallic
corrosion are composition, pH and, in particular, electrical
conductivity, which affects both the intensity and distribution
of corrosion.
The severity of corrosion often increases with increasing
electrical conductivity of the electrolyte because, in practice,
high conductivity is often caused by the presence of aggressive
ions such as chloride, or by acid or alkali.

I dont think that the water in most cooling systems is a very effective electrolyte, and ergo, the current generated by said galvanic cell will be minimal. All that is needed to prevent said coprrosion is an equal and oposite voltage and current.