SYSTEM OPERATION
(con’t)
Charge Voltage
For both 8A & 8G batteries the following voltage settings
should be followed:
Charge / Absorption / Equalize
13.80V to 14.60V @ 77°F (25°C)
Float / Standby
13.50V + .01 @ 77°F (25°C)
The charger must be able to maintain the system voltage
within ± 0.5% of the desired level at all times.
Note: Divide values in half for 6-volt battery(ies).
Temperature Compensation
Battery voltage should be adjusted for ambient
temperature variations.
3mV per °C (1.8°F) per cell
18mV per 12V battery
9mV per 6V battery
For temperatures above 77°F (25°C) subtract and
for temperatures below 77°F (25°C) add.
Consult Voltage Compensation Chart in
Appendix A for temperature compensation voltage
maximum and minimum limits.
The average battery operating temperature should not
exceed 95°F (35°C) and should never exceed 105°F
(40.5°C) for more than an eight-hour period. Operating at
temperatures greater than 77°F (25°C) will reduce the
operating life of the battery. If operating temperatures
are expected to be in excess of 95°F (35°C), contact
MK Battery for recommendations.
Discharging at temperatures less than 77°F (25°C) will
reduce the capacity of the battery.
Charge Current
To properly determine the amount of charge current
required the following variables are to be considered:
• DoD (Depth of Discharge)
• Temperature
• Size & efficiency of the charger
• Age and condition of battery(ies)
Maximum charge current should be limited to 30% of the
C20 Ah rate for the battery(ies) being used in the system.
Example: 8G24 C20 rate – 73.6Ah
Max. recharge rate: 73.6Ah x 0.3 = 22.1A
Consult Charging Current vs Charging Time chart in
Appendix A as a guide line to determine recharge time
from 0% to 90% state of charge at an initial charge current.
Discharge Voltage Curve
To estimate battery voltage during a constant current
discharge at various DoD (Depth of Discharge) consult
chart Discharge Voltage Curve in Appendix A.
NOTE: Battery voltage can vary depending on
temperature, age, and condition of battery.
RECORD KEEPING
Voltages, Temperatures & Ohmic Readings
Consult User Manual of specific application for
additional Safety & Operating requirements.
Record keeping is an important part of battery mainte-
nance and warranty coverage. This information will help
in establishing a life history of the battery and inform the
user if and when corrective action needs to be taken.
(Refer to Appendix B, Battery Maintenance Report).
After installation and the batteries are at a fully charged
condition, the following data should be recorded:
Depending on application, some of the following
recommendations may not apply.
• Battery and/or string terminal voltage
• Charger voltage
• Individual battery float / charge voltages
• Individual battery ohmic readings**
• Ambient temperatures
• Terminal connections should be checked to verify all
connections are properly torques. Micro-ohm readings
should be taken across every connection. Refer to meter
manufacturer’s instructions for proper placement of
probes. If any reading differs by more than 20% from its
initial installation value, re-torque the connections. If the
reading still remains high, clean contact surfaces
according to installation portion of this manual.
** Note: To provide accurate / consistent values,
battery(ies) must be fully charged, at same temperature
and probes placed at same location each time readings
are taken.
®
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