Why bother?

During the normal discharge process, soft lead sulfate crystals are
formed in the pores and on the surfaces of the positive and negative
plates inside a lead-acid battery. When a battery is left in a
discharged condition or is continually undercharged, some of the soft
lead sulfate is re-crystallizes into hard lead sulfate, which cannot
be reconverted during subsequent recharging. This creation of hard
crystals is commonly called “sulfation” and is the most common cause
of failure of lead-acid batteries while in storage. The longer
sulfation occurs, the larger and harder the lead sulfate crystals
become. These crystals lessen a battery’s capacity and ability to be
recharged. People kill more deep cycle batteries (due to sulfation)
with poor charging practices, than die of old age. This is because a
deep cycle battery is typically used for short periods and then is
stored the rest of the year why they are slowly discharging. In
contrast, a car or motorcycle battery is normally used several times a
month, so sulfation rarely becomes a problem.

Sulfation is a result of lead-acid battery discharge while in storage,
which is a consequence of parasitic load and natural self-discharge.
[Parasitic load is the constant electrical load present on a battery
while it is installed in a vehicle even when the ignition key is
turned off. The load is from the continuous operation of appliances,
such as an emissions computer, the clock, a security system, and the
maintenance of radio station presets in a radio.] While disconnecting
the negative battery cable will eliminate the parasitic load, it has
no affect on the other problem, the natural self-discharge of battery.
Thus, sulfation can be a huge problem for lead-acid batteries not
being used while in storage or sitting on a dealer’s shelf, in a
basement, or in a parked vehicle.


How do I prevent sulfation?

The best way to prevent sulfation is to keep a lead-acid battery fully
charged because lead sulfate is not formed. This can be accomplished
three ways. (1) The best solution is to use a charger that is capable
of delivering a continuous “float” or “trickle” charge at the battery
manufacturer’s recommended float or maintenance voltage for a fully
charged battery. 12-volt batteries and depending on the battery type,
usually have fixed float voltages between 13.2 VDC and 13.6 VDC,
measured at 70 degrees F (21.1 degrees C) with an accurate (.5% or
better) digital voltmeter. For a six-volt battery, measured voltages
are one half of a 12-volt battery. Charging can best be accomplished
with a microprocessor controlled three- or four-stage charger, such as
a, Battery Tender (Deltran), Truecharge (Statpower), BatteryMinder,
Schumacher, ChargeTek, etc., or by voltage-regulated (or constant
voltage) charger set at the correct float voltage. By contrast, a
cheap, unregulated “trickle” charger can overcharge a battery and
destroy it. (2) A second method is to periodically recharge the
battery when the State-of-Charge drops from 100% to 80%. At 70
degrees F (21.1 degrees C), a battery with 100% State-of-Charge
measures approximately 1.261 Specific Gravity or 12.63 VDC and 80%
State-of-Charge measures 1.229 Specific Gravity or 12.47 VDC.
Maintaining a high State-of-Charge tends to prevent irreversible
sulfation. The recharge frequency is dependent on the parasitic load,
temperature, a battery’s condition, and plate formulation (battery
type). Temperature matters! Lower temperatures slow down
electrochemical reactions and higher temperatures speed them up. A
battery stored at 95 degrees F (35 degrees C) will self-discharge
twice as fast than one stored at 75 degrees F (23.9 degrees C). (3) A
third technique is to use a solar panel or wind generator to float
charge the battery. This is a popular solution when AC power is
unavailable for charging.


So how do I store my battery?

There are three simple steps. First, if the battery has filler caps,
check the electrolyte (battery acid) level in each cell. If required,
add only distilled water to the recommended level, but do not
overfill; clean the top of the battery and posts; and fully charge the
battery. Second, store the battery in a cool (above freezing), dry
place where it can be easily recharged. Finally and most importantly,
prevent sulfation by keeping the battery charged above the 80%
State-of-Charge level!

For additional free consumer information on car (and motorcycle) or
deep cycle batteries, please go to http:/www.uuhome.de/william.darden/