Battery Fuse Removal Test

This test temporarily removes the battery connection to the MARK/15. The new voltage display will indicate if the unit is working properly. Note: when the fuse is removed, it is normal for the “CHARGING” and the “CHARGED” lights to both go on (during the daytime) and to hear a faint buzzing. Remember to replace the fuse immediately after testing.

Procedure: During a sunny period when the battery voltage is over 10 volts, remove the BATTERY fuse. Note the "BATTERY VOLTAGE" reading. Compare the reading to the options below.


· VOLTAGE READS FROM 10.0 TO 15.0  VOLTS*  -  If the new reading is in this range, perform another step. Note the exact voltage value. Replace the fuse. Now, again note the value.  Did the value change ?

· VOLTAGE: 10 - 15V.* AND   CHANGES WITH FUSE REMOVAL  -  This is the correct reaction and the unit is working properly.  If problems still exist, consider checking the charging set-point at the display (3rd position) and checking for a voltage drop

· VOLTAGE: 10 - 15V.* AND   READING DOES NOT CHANGE WITH FUSE REMOVAL  - If the meter stays the same before and after removing the fuse, this indicates the MARK/15 may not be connected to the battery. BAD CONNECTION: BATTERY.


· BATTERY VOLTAGE” READING IS BLANK -  If the meter is blank, this means that the solar array is bad or disconnected or that the MARK/15 is defective. If possible, perform this step. Disconnect the array(+) connection at the MARK/15. With a volt meter, measure the voltage of the array by measuring the array wires where they meet the MARK/15.

· VOLTAGE DISPLAY BLANK AND ARRAY VOLTAGE AT MARK/15 IS ZERO  -  This indicates that there is a problem with the array or array connection. · VOLTAGE DISPLAY BLANK AND ARRAY VOLTAGE GREATER THAT 16V.

Check Array Fuse. If Array fuse is OK, the MARK/15 is defective.


· VOLTAGE READING IS GREATER THAN 16.0 VOLTS* - This would indicate that the MARK/15 is defective. The meter is displaying the panel voltage, which is usually about 16-22 volts*.

* Voltages above are for 12 volt systems.  For 24 volt systems, double the listed value.