Fact or fiction: Humid climates can cause batteries to go bad.

Dear Car Talk

Dear Car Talk | Feb 01, 2000

Dear Tom and Ray:

A friend of mine visiting New Orleans had his battery go bad. He was told
by the service technician that in the humid and warm climate of Louisiana,
an electrical connection could establish itself across the battery
terminals and cause a short. This has an air of plausibility about it.
Moisture-saturated air, near enough to the ocean to have salt ions floating
around in it, might be considered a weak electrolyte fluid. Does this
explanation have "potential"? -- Joe

TOM: Clearly, it has potential, Joe. You bought it!

RAY: Unfortunately, it's complete battery wash.

TOM: It does have that "air of plausibility" about it, like all good, bogus
theories do. There's just enough science in there to make you think, "Hmm,
sounds good. ..." But if that theory were true, every coastal community in
the United States would have an army of dead batteries every time it rains
(which makes the relative humidity 100 percent, right?).

RAY: The truth is, it takes more than salty, humid air to make a meaningful
electrical connection between the battery terminals. I'd say it's more
likely that your friend left a door ajar after spending a late night on
Bourbon Street. And then the dome light ran down the battery overnight
while he was sleeping off all those Lucky Dogs. That has a greater air of
plausibility, wouldn't you say?

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