MONITORING
The system operation can be monitored by the meters and the status lights.
DIGITAL DISPLAY: The Digital display of the MARK/(15,20) provides metering of four
parameters, selected by a front panel slide switch.
1
st
POSITION - "BATTERY VOLTAGE": This displays the battery voltage. The battery
voltage is a general indication of battery condition, or capacity. Battery voltage will be higher
when the battery is being charged, with the increase in voltage depending on the amount of
charge current. When charging stops, the voltage will immediately drop down.
For most systems, a fully charged battery that is not being charged or discharged will be at
about 12.6-12.8 volts. The normal range of a 12 volt battery is about 11 to 15 volts. A voltage
below 11 volts usually indicates a dead battery, and over 15 volts is almost always an over-
charged battery. It is best to keep the batteries above 11.5 volts and below 14.5 volts for
maximum battery life and performance.
2
nd
POSITION - "ARRAY CURRENT": This displays the amount of current flowing from the
solar panels to the batteries or loads.
The solar array current reading can be used to optimize the array tilt angle by moving the
array and noting when current is maximized. Consult the panel supplier or literature for rated
output to see what the output should be for the total number of panels in the system under
ideal conditions. If the charging current seems low, refer to the SOLAR PANEL PROBLEMS
section (Page 18).
3
rd
POSITION - "CHARGE SET-POINT": This position displays the charge termination
voltage set-point that the controller is currently set to. This setting can be used to verify the
termination set-point, or for set-point adjustment. See “CHARGE SET-POINT
ADJUSTMENT” section (Page 11).
4
th
POSITION - "BATTERY VOLTAGE (bar-graph off)": This position is identical to the 1
st
position described above except that the battery bar-graph display is turned off. Use this
position if current consumption is a special concern.
“CHARGING” LIGHT: The "CHARGING" light will be on when the battery is charging. When
charging, virtually all the power available from the solar array will pass through to the battery.
“CHARGED” LIGHT: The "CHARGED" light will be on when the battery is fully charged. After
the battery has reached the charge termination voltage, the charging will stop and the
“CHARGED” light will go on. This light will remain on until the battery voltage drops down to
the charge resumption voltage.
12