Why batteries get damaged
According to one of the worlds leading battery manufacturers, there are basically
three reasons why a battery malfunctions.
- Leaving a battery stood, even for quite short periods in a very discharged or even
slightly discharged condition WILL damage your battery! This may only be a few days,
or a week or so. Its long enough! It causes them to become chemically damaged through
sulphation. This is the MAJOR cause of ruined batteries. They then will hold less
charge or go "flat" sooner than they did before. In extreme cases they cannot even
be recharged at all. And the situation gets worse the more often you do this. So
if you leave your car or boat unattended and unused for over a week you really do
NEED to have a maintenance charger left connected up to it permanently. It may well
start your car/boat still, but you definitely will have caused "some" damage to
it. Modern cars slowly "use up" the batteries charge even when parked up, with engine
management systems, alarms, clocks, remote locking, radio station memories etc all
drawing some power at all times. So at an airport for example you would do very
well to disconnect your battery until you return! The battery will still lose SOME
charge (due to its natural internal losses) but will be much less damaged. A good
battery will have enough energy left to start your car after up to a year if it
has been disconnected, but may be totally dead after a month if left connected in
some cars!
- Discharging any lead acid type battery too "deeply" as this destroys the active
plate material. Deep Cycle batteries can survive typically 300 80 percent discharges
only. A typical car starter battery will survive only 25 or so of these 80% discharges
before it is ruined! Starting a car typically only removes 5 to 15 percent of the
charge so used regularly, and KEPT PROPERLY CHARGED during long periods of inactivity
a starter battery will last for many, many years.
- Overcharging... A cheap charger just "keeps charging" long after the battery is
fully charged. Modern maintenance free batteries cannot cope with this! Years back
when we all used wet acid batteries, all that happened was that the electrolyte
"gassed" and its level dropped. Later you just topped it back up. Modern batteries
do not gas at all, and are sealed. If overcharged as all taper or cheap chargers
will do - they WILL gas, and this causes permanent loss of electrolyte and battery
damage. A modern logic controlled pulse charger like the one on this page prevents
this and can (and should) be left connected all the time. They both charge safely,
AND maintain your battery.
Remember your battery is like a piggy bank. If you take out more than you put in
it will become empty! And batteries do not actually "like" being discharged. The
secret to long battery life is to discharge them as little as possible! (not always
possible of course!) and to charge them back up as soon as you possibly can! But
NOT overcharge them. This requires a complex matched charger that suits your batteries.