Tom Gardner wrote:

Mom's car, sitting for 2.5 years had to be moved. The Interstate 72 mo.
battery that was put in just before storage won't take a charge...no
surprise, I put another new one in. Rather than turning in the core for $12
I will get it replaced under warranty. Is there any way to keep a new
battery on the shelf for extended periods of time? Should I keep it on a
trickle charger? Is it an urban myth that sitting on concrete will kill it?



Was the car sitting outside in freezing weather? If it was and the
battery self discharged (about 3% a month) and then froze, it may well
have be ruined by the expansion of the freezing electrolyte. But if it
wasn't frozen, read on.

When you say "won't take a charge" do you mean that it will accept a
reasonable charging current for several hours but then not deliver any
significant current to a load? If that's it, the battery has croaked.

Or, do you mean when you hook it up to a charger it doesn't draw any
current?

I've seen the latter happen with "run down" batteries, but if I turn the
charging voltage way up and leave them connected to the charger, after
15 minutes or so they suddenly start drawing reasonable charging current
and will then charge normally. It's some sort of battery chemistry thing
I never learned the reason for.

Yes, trickle charging an unused battery with a "smart" charger is a good
idea.

The concrete thing is an urban myth. Back when battery cases were made
of asphalt or hard rubber they used to store them on wooden pallets at
garages and battery shops rather than on the concrete floor. The reason
for that was so that if the battery jockeys set them down "hard" the
case didn't crack like it might if it was clunked down onto concrete.

Modern battery cases can stand much more knocking around.

'Course if you cracked the case by setting it down hard on concrete, the
acid would leak out of one or more cells and you WOULD find the battery
dead when you went to use it.


Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."