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Factors Affecting Battery Life
State of Health
As batteries age, their overall health diminishes. The biggest sign that a
battery’s health has declined is seen as reduced capacity. Without the SG200,
the easiest way to see if this is happening is to monitor the time it takes
a battery to charge using the same charging source. If the time to charge
decreases over time, it is because the capacity has diminished. All lead-acid
batteries age due to sulfation as well as shedding, where lead falls off of the
plates and settles on the bottom of the battery.
There are several factors that affect the health and lifespan of a battery or
battery bank. For most lead-acid batteries, the two most important factors
affecting lifespan are depth of discharge/cycle count, and the concept of fully
charing the battery after each discharge. Each of these effect the mechanical
and chemical properties of batteries.
Sulfation and Shedding
At the mechanical/chemical level, there are two primary conditions that reduce
the life, or State of Health of a battery. They are Sulfation and Shedding.
Sulfation occurs when lead sulfate, formed naturally during battery use, is
converted to a more stable crystal form that covers the negative lead plates in
a battery. This happens when a lead acid battery is left in a partially charged
state. Different battery manufacturers have devised different methods and
chemistries to combat this effect, with varying degrees of success. Sulfation is
accelerated by Partial State of Charge (PSOC) cycling and deeply discharging
batteries.
Shedding in another naturally occurring phenomenon. During use, lead is
shed from the plates and falls to the bottom battery. When enough lead has
gathered, a partial-short starts to occur in the battery which will drain the
capacity on it own and hasten the battery’s demise.
In extreme instances, a battery can suffer a mechanical failure internally
and will quickly short a cell with no chance of recovery. When this happens
the battery must be replaced. If left in place the other cells can be
overcharged,risking excessive heat and fire.
Summary of Contents for SG200
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