EN / SCM20 & SCM40 PWM User’s Manual
5
2 OPERATION
2.1 GENERAL
The Mastervolt Solar ChargeMaster is a fully automatic
battery charger which converts power from photovoltaic
(PV) array to a regulated battery voltage. The Solar
ChargeMaster will automatically adjust itself to a 12V or a
24V system. Under normal circumstances the Solar
ChargeMaster remains switched on with the PV-array and
batteries connected.
If power from the PV array is sufficient, the Solar
Chargemaster will initiate the charging process.
WARNING
The Solar Chargemaster has no on/off switch.
Charging will be initiated as soon as power from
the PV-array becomes available.
The Load output of the Solar Chargemaster switches off if
one of the following fault conditions occurs: overload, short
circuit, overheating or under and over voltage. The Load
output switches on again after one minute if the Solar
Chargemaster recovers from these fault conditions.
CAUTION!
The Solar ChargeMaster is not protected
against:
Excessive overvoltage on the Solar input
Surges inducted by lightning.
2.2 MAINTENANCE
No specific maintenance to the Solar Chargemaster is
required. Examine your electrical installation on a regular
base, at least once a year. Defects such as loose
connections, burnt wiring etc. must be corrected
immediately.
If necessary, use a soft clean cloth to clean the casing of
the Solar Chargemaster. Do not use any liquids or
corrosive substances, such as solvents, alcohol, petrol or
abrasive components.
In the event of decommissioning, refer to section
3.9
2.3
THREE STEP CHARGE ALGORITHM
See Figure 3. Battery charging is accomplished in three
automatic stages: BULK, ABSORPTION and FLOAT.
Figure 3: Three step charge system
BULK: At this stage the charger delivers its maximum
current for quick charging from 0 to 80%
ABSORPTION: The charger has reached its maximum
charge voltage and the charge current will slowly
decrease until the battery is charged up to 100%.
FLOAT: This stage begins once the battery is fully
charged. The battery remains in fully charged state.
By installing the battery temperature sensor (not included;
see section 5.3 for ordering information) the charge
voltages are automatically adapted for deviating
temperatures.
Figure 4: Temperature compensated charging
See Figure 4. When the battery temperature is low, the
charge voltage increases. On the other hand, when the
battery temperature is high, the charge voltage is
decreased. Over charge and gassing are prevented this
way. This will extend the life of your batteries
12V
24V
battery temperature (
°
C)
charge voltage (V)