Date: Sun, 8 Apr 2001 22:04:15 -0500 (CDT)
From: David Scheidt <dscheidt@tumbolia.com>
Subject: LRO: Battery question
>I've got this battery that doesn't hold a charge. Sort of. What it
does is not produce starting current, but only if it's been sitting.
It's got 13 something volts, hit the starter and the starter doesn't
spin.
Couple of things to check before tossing the battery completely.
First, make sure the battery connections are good. A dirty or
corroded connection can give enough resistance to keep a
starter from working if the battery voltage drops even a little,
like over a period of time. Second, make sure the ground
connection is good to the frame or wherever it's attached
on your vehicle.
However, batteries can go bad on their own. They can suddenly
reverse polarity or short out. Also, as batteries sit, the acid
and water separate somewhat. What you end up with is a
battery that's only got perhaps a third of its effective plate
depth working for you. (I learned all this because we
just had an inverter/charger installed on our trawler
and the guy told me more
about batteries than I thought there was to know). Anyway,
as the batteries sit, you slowly lose the power (cranking
power) in the battery. It will indicate 12-14 volts just
fine, but there's just no power there to do much work.
The solution is called "equalizing"
the battery. What you do is deliberately overcharge it
for about eight hours. It makes nasty gas and boils
water out of the cells, but the important thing is that it
re-mixes the acid and water and gets all the accumulated
sulfide off the plates so that the entire plate surface is
working for you again. The inverter/charger we have on the
boat has this "equalizing" function built in. Most smaller automotive
chargers do not. By the way, this is not something you do
a lot and frequently. Most battery manufacturers recommend
doing this every ten to twenty cycles (a cycle is when you
run a battery almost completely dead, as you do with the house
power batteries on a boat.) So equalizing only needs to be done
perhaps two or three times a year. You don't run a car battery dead
on a routine basis, so you can't use cycles to judge when to
equalize. So maybe once a year would make sense on a car,
if it's worth doing at all.
If you can find a charger that will overcharge your battery
(about 16 volts is what you want to pump in there), you might
want to try that. Just remember to do it in a well ventilated area
and don't turn on any accessories in the car that might be
damaged by 16 volts DC. Probably the best thing is to take the
battery out of the vehicle altogether. And make sure it doesn't
run low on water during this process.
However, it may be less hassle simply to discard the battery
and get a new one.
___________________________
C. Marin Faure
(original owner)
1973 Land Rover Series III-88
1991 Range Rover Vogue SE
Seattle
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