Specialty Concepts ASC - Manual (Page 22)

A S C
– F I E L D T E S T P R O C E D U R E
You can determine if an ASC is operational. An active solar panel is required. An accurate digital volt-
meter is recommended although a simple analog volt-meter may also be sufficient.
STEP 1: Preparation –
1) Put a solar panel in full sun. Remove any connections. Measure the open circuit voltage (voc)
of the panel (meter(+) to panel(+); meter(–) to panel(–) ). It needs to be 17 volts* or higher
to perform the following tests.
2) Remove any connections from the ASC.
STEP 2: Test FET’s (power transistors) – A unit with an shorted FET will not charge a
battery. One with an open FET may overcharge the battery.
1) With all ASC connections removed, connect the panel(+) to the ASC’s “ARRAY(+)”; panel(–)
to the ASC’s “ARRAY (–)” (no battery connection).
2) Measure voltage at BATT(+) and BATT(–) terminals on the ASC. The reading should be
between 14.0 and 15.0 volts*. (Units with Option-A (Temperature Compensation) and
Option-F (Adjustable Set-points) may vary beyond this range).
A very high reading (16-20 volts*) would indicate an open FET, or very low reading (2-5
volts*) would indicate a shorted FET. Units with open or short FET’s are defective
STEP 3: Test Blocking Diode – A unit with a shorted diode may blow any in-line fuses
and damage the power FET (see above). A unit with an open diode will not
charge the battery.
1) With all ASC connections removed, connect the panel(+) to the ASC’s “ARRAY(+)”; panel(–)
to the ASC’s “BATT(+)” (no battery connection).
2) Measure voltage at ASC. Meter(+) to ASC’s ARRAY(+), meter(–) to ASC’s BATT(+)
terminals. The reading should be .3 to .6 volts. A very high reading (16-20 volts*) would
indicate an open diode, a very low reading (0 to .2 volts) would indicate a shorted diode.
Units with open or shorted diodes are defective.
STEP 4: Test/Inspect Temperature Compensation Cable (units with Option-A only)- An
ASC with a cut or damaged cable will not charge the battery.
1) Inspect the cable and sensor tube for cuts or damage.
2) If the sensor cable is cut and the sensor itself is OK, the two wires within the cable can be
reconnected and soldered. There is no polarity with the two wires. Protect this connection
with electrical tape.
If an accurate digital volt meter is available…:
3) With all ASC connections removed, connect the panel(+) to the ASC’s “ARRAY(+)”; panel(–)
to the ASC’s “ARRAY(–)” (no battery connection).
4) Measure voltage at BATT(+) and BATT(–) terminals on the ASC. The reading should be about
14.0 to 15.0 volts*.
5) Expose the temperature sensor to a substantially higher or lower temperature for 30 seconds
(Example: attach the sensor to the side of a cup of hot coffee or ice water). With colder
temperatures, the voltage will rise (about ½
volt* per 16
°
C (30
°
F)). Hotter temperatures will
lower the voltage. Changes with temperature can be subtle. A unit that does not see a
change with temperature could have a defective sensor.
* Voltages above are for 12-volt systems. For 6-volt systems, use half the listed voltage. For 24-volt
systems, multiply by 2. For 36 volts, multiply by 3. For 48 volts, multiply by 4.