discharges greater than 5% of capacity will result in a longer battery life.
(Batteries are ALSO rated at the number of charge cycles they can support. A
battery discharged to 80% DOD may have a rating of 1500 cycles, however if
only discharged to 20% DOD the number of charge cycles increases to 4000)
Discharges of 50% DOD (or
less) are recommended.
(Discharge to no less than 12.1V on a 12V system or 24.2 within a 24V
Sulfation of Batteries starts when specific gravity falls below 1.225. This
is 25% of battery capacity. Within a 12V battery this would be when voltage
measures less than 12.4V or 24.8V within a 24V battery array. Sulfation coats
the battery plates reducing and eventually destroying the capacity of the
battery or stated otherwise, its ability to generate Volts and Amps.)
The ABSOLUTE MAXIMUM
DISCHARGE is to 80% of battery capacity, any deeper discharge and your
batteries will suffer irreversible damage.
(80% discharge is down to 11.66V on a 12V system or 23.32V within a 24V
Most experts recommend
operating batteries from 50% to 85% of full charge. A periodic equalization
charge is a must when cycling from 50% to 85% of full charge.
(The 50-80% range for a 12V system is discharge to between 12.1 and 12.5V.
The 50-80% range for a 24V system is 24.2 to 25V).
discharged must not be left discharged for any length of time.
(When batteries are discharged lead sulfate ions clump on to the negative
battery plates as they lose their charge to the battery plate. These ions are
disorganized or chaotic as they attach themselves to the battery plates.
However, over time these proximal ions re-arrange themselves into an organized
crystalline structure forming sulphate crystals. Sulfate crystals are non
conductive, forming a barrier to future chemical/electrical reaction at the
battery plates and electrolyte. Sulfate crystals are very difficult to
dissolve once formed.)
Batteries should NOT be
regularly discharged by only
a few percent because sulphate builds up irregularly during the first phase of
the discharge cycle. Try to ensure your batteries are discharged to at least
five or six percent of capacity.
Lead acid batteries do not
develop a memory and need not be fully discharged before recharging.
Batteries should be
charged as soon as possible after each period of use.
(see point F above)
Batteries that charge up
but cannot support a load are most likely sulfated or corroded and should be
(Refer to our Battery Maintenance document for proper testing procedures.
Lack of cycling BATTERY STORAGE
Completely charge the
battery before storing.
(This removes the sulphate ions from the battery plates so that they canít
organize into crystals.)
Clean the batteries.
(A light skim of acid on a battery will attract water [hydroscopic], water
with the acid can act as a conductor and short the battery or the acid can
corrode wires and terminals.)
Store the battery in a
cool, dry location, protected from the elements.
(Batteries are chemically active, storing them in a cool place slows the
chemical reaction. Dry because you donít want condensation or water to short
(even a light short over a long period of time will discharge a battery.)
During storage, monitor
the specific gravity (flooded) or voltage. Batteries in storage should be
given a boost charge when they show a 70% charge or less.
Completely charge the
battery before re-activating.
(Lead acid batteries slowly self discharge over time.)
After charging, for
optimum performance, equalize the batteries (flooded) before putting them back
into service. Refer to our Battery Equalizing document for this procedure.