battery charging and death

SJ syljay at
Wed Feb 9 16:26:29 EST 2005

> From: "Ed Kellock" <ekellock at>
> Subject: battery charging and death
> My Coupe GT had a new battery last July.  Over the last couple months the
car has sat unused for longer periods of time.  It required a jump and then
would be okay until it sat again for several days.  This is generally not a
common problem for the car.
**** Ya, you killed the battery. Car batteries are designed to be fully
charged ALL THE TIME. Otherwise, they sulphate and wont hold a charge.
For a car that sits around and only gets driven infrequently, you really
should get one of those solar powered chargers. They put out about 150 ma at
14.5 volts.

> So did I kill it?  I was going to use the KnowledgeBase item to check for
a drain on it, but I figure that's moot until I get a battery that will hold
a charge first.
**** My 88 5kq has a 16 ma draw on it when shut off and the interior lights
are out.

> Do peiods of inactivity kill a battery?  Or just an already compromised
battery?  Would a constant slow drain kill it?  Did I just get a bad battery
from the get-go?
***** Every time the battery gets low, it sulphates. Letting a battery go
dead is sure death for the battery.

Most car batteries are undercharged. Around town driving never fully charges
up a battery.

      Why Batteries Fail
      When a lead-acid battery is discharged, a soft lead sulfate material
forms on the battery plates. During the battery's recharge, this material is
lifted off the plates and recombined into the battery's electrolyte
solution. If, however, the battery is left in a partial state of discharge
for as short as 3 days, the lead sulfate material will begin to harden and
crystallize, forming a permanent insulating barrier. As this barrier becomes
thicker and thicker, the battery's ability to accept a charge or deliver
energy is diminished, resulting in the perception that the battery is no
longer usable. The accumulation of such deposits, otherwise known as
sulfation, is the most destructive process in the life of any lead-acid

85 Dodge PU, D-250, 318, auto
85 Audi 4k - - sold but still on the road
88 Audi 5kq
90 Audi 100q

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