Exide Technologies Battery Charging and Storage Guidelines - Manual (Page 2)

Note: This information applies ONLY to 8 volt single lead acid batteries of the types listed.
WARNING: Data is not necessarily valid for conditions where multiple 12 volt batteries are connected in strings (series or parallel)
See notes below the data table for battery strings.
Recommend boost at or
before this SOC before
battery use.
Lead Acid Battery Types
Bulk Charging
(Constant Current)
8 volt Battery
Absorption
Charging (Constant
Voltage)
8 volt Battery
Float Charging
(Constant
Voltage)
8 volt Battery
Trickle Charging
(charge maintenance
during extended
storage)
Temperature Compensation
Open Circuit
Voltage (OCV) @
10% State of
Charge (SOC)
Open Circuit
Voltage (OCV) @
50% State of
Charge (SOC)
Open Circuit
Voltage (OCV) @
60% State of
Charge (SOC)
Open Circuit
Voltage (OCV) @
70% State of
Charge (SOC)
Open Circuit
Voltage (OCV) @
90% State of
Charge (SOC)
Special notes Other Guidelines
Flooded/Wet Deep Cycle
(Antimony)
Exide Golf Cart
Exide Special Heavy Duty
Charge at a constant
current rate of no more
than 10 times I 20 to a
voltage of 9.78V
(example; For
C20=100Ahr, the max
charge current is 10x5A
or 50A).
Charge with 9.78V -
9.91V limit for 12 to
24 hrs or when
current drops below
1% of the C20 rating
(example;
C20=100Ahr, the low
current shut off is
1%x 100 or 1A).
8.78v - 8.91v
Charge voltage on
point - 8.25v
Charge voltage off
point - 8.78v
Limit current to 0.4
times I 20
Charging Temperature Compensation: All the listed
charging voltages are appropriate for a temperature range
of 15-25ºC (68-77ºF). For average operating
temperatures below this range (colder than) the
maximum voltage set point should be compensated with
an increase at a rate of 0.063 Volts Per Cell (0.25 Volts
for a 8 v battery) for every 10ºC (18º F.) For average
operating temperatures above this range (warmer than)
the maximum voltage set point should be compensated
with a decrease at a rate of 0.063 Volts Per Cell (0.25
Volts for a 8v battery) for every 10ºC (18º F.)
Example: at 95ºF and 9.4 volt set point Corrected
Voltage = 9.4 + (((95-77)/18) x (0.25)) = 9.65 volts
7.65v 8.04v 8.16v 8.25v 8.45
Battery Temperature: Batteries should be brought to a temperature
of at least 60ºF (15ºC) for most efficient charging and below 85ºF
(30ºC) to limit over heating effects.
AC Ripple Charge Limitations: Some DC chargers will have what
is referred to as an AC ripple wave-form to the charging input.
Excessive ripple can cause battery heating and gassing resulting in
reduced life. Ripple current excursions during the float charging
phase should not exceed 5 Amps for every 100 AH of nominal
capacity (Example: 4 amps for 80 AH battery) Ripple voltage
excursions during float should not exceed +/- 5% of the float voltage.
(Example: +/- 0.46 volts at 9.2 volts)
Operating Temperature: The recommend operating temperature
range is 10ºC - 30º (50ºF -86ºF) for optimal operation. Lower
temperatures will limit capacity output. Higher temperatures may
reduce life. Maximum operating temperature is 50ºC (122ºF). Storage: For open circuit storage it is recommended that the
battery be stored indoors in a clean, dry location. Never store
(or operate) in an airtight enclosure. Keep away from direct
heat sources. Storage temperature should be between 50ºF -
77ºF (10ºC - 25ºC). Batteries should be disconnected from all
potential load sources during storage. Batteries should be
fully charged prior to storage. Batteries should be boost
charged every 6 months or when the battery voltage reaches
8.16 volts. Storage at elevated temperatures will result in
accelerated rates of self discharge. A general rule of thumb is
that for every 18ºF (10º) above 77ºF (25ºC) the time before
boost charging will be halved. Storage without proper charge
can result in excessive sulfation and can be detrimental to
battery performance and life.
Helpful explanations
1) Calcium and Antimony notations refer to metal alloy additives used in battery grids. These alloys have small effects on the charge voltages.
2) Bulk charging is the rapid and most aggressive re-charge method. It is typically only used in applications that need rapid recovery for deeply discharged batteries. Battery cooling may be required.
3) Absorption charge is an aggressive method where current is allowed to diminish as the battery naturally comes to full charge. It can be used for deeply or less deeply discharged batteries. Battery cooling may be required.
4) Float charge is a stage where the battery is charged at a lower voltage to slowly "top off" a slightly discharged battery.
5) Trickle charging is used to maintain charge during a long storage period. Charge voltage on/off points are very important to hold charge without damaging battery life.
6)
State of Charge (SOC) is a highly variable number. Data should be taken as reflective of technology listed, but actual performance may be plus/minus 0.10 volts.
7) The reference to C 20 in the table above means 20 hour capacity as measured in amp-hours (Ahr). Similarly, I 20 refers to the current discharge rate for 20 hour capacity. For example, a C 20 of 100 Ahr would have an I 20 of 5 amps (5 amps times 20 hours = 100 Ahr)
8) To estimate C 20 capacity for 8 volt GC batteries - multiply RC minutes at 56 amps times 1.35 = C 20 capacity. For example, RC minutes at 56 amps is rated at 110 minutes. The C 20 estimate is 110 times 1.35 = 149 Ahr.
For 16 volt systems that are comprised of two (2) 8 volt batteries connected in series that are charged with 16 volt chargers (with no parallel battery connections)
1) All charging voltages double (due to series connection) as listed in the above table.
2) All charging currents remain identical to 8 volt numbers as listed above (due to the series connection.)
3) All charging times remain identical to 8 volt numbers as listed above (due to the series connection.)
For 24 volt systems that are comprised of four (3) 8 volt batteries connected in series that are charged with 24 volt chargers (with no parallel battery connections)
1) All charging voltages increase X 3 (due to series connection) as listed in the above table.
2) All charging currents remain identical to 8 volt numbers as listed above (due to the series connection.)
3) All charging times remain identical to 8 volt numbers as listed above (due to the series connection.)
For 8 volt battery strings using two batteries in parallel connection (positive to positive and negative to negative)
1) All charging voltages remain the same as listed in above table.
2) All charging currents double as listed above in order to charge in same amount of time as listed in above table.
3) All charging times double as listed in above table if current stays as listed in the above table..