SC30 Manual

Installation and Operation Manual
4
To assist in understanding the performance of your solar system the SC30 includes a solar charge amp-hour counter. The amp-hour counter displays
in whole numbers with no decimal point up to a maximum count of 999 amp-hours. The number displayed is the total solar charge amp-hours accumulated
since the last time the amp-hour counter was cleared. Amp-hour production varies widely with operating conditions, but as a very broad brush approximation
each 100 watts of PV modules can deliver up to a maximum of about 30 amp-hours per day. Any partial shading, lower sun intensity, shorter days, or time
spent in Absorption or Float where current is intentionally reduced will decrease amp-hours produced. The present amp-hour count may be cleared by
pressing Display Select for 5 seconds while viewing amp-hours on the display.
BATTERY LEVEL GRAPHIC
The SC30 provides a battery level graphic on the front panel which indicates approximate battery level versus battery voltage. Generally a higher voltage is
better than a lower voltage. Note that the graphic does not illuminate.
A battery that is being charged will typically range in voltage from about 12.5 volts after charge commences, to perhaps 14.0 volts or greater when the
battery is highly charged. Once charge stops and the battery begins discharging and delivering power to a load it is normal for battery voltage to drop. A battery
under a light load of about 1 amp per 100 amp-hours of battery capacity may range between about 12.5 volts when the battery is full, down to perhaps 12.0 volts
when the battery is about 50% discharged. Battery voltage during discharge will tend to be higher under light load and lower under a heavier load.
Do not think of these voltage values as absolutes but rather as a broad brush indication of battery level. Voltage at a particular state of charge will vary with
battery size, age, construction, temperature, and with the level of charge or discharge current. Most battery manufacturers recommend not discharging below
about 50% DOD (depth of discharge) to promote improved battery performance and life. Avoid allowing battery voltage to drop below about 11.5 volts, and NEVER
allow battery voltage to drop below 10.0 volts.
FRONT PANEL OPERATION & INDICATORS
FIGURE 1
3-STAGE CHARGE CONTROL
The SC30 is factory configured for a 3-stage charging process, Bulk, Absorption and Float. The 3-stage charge process provides a somewhat higher
charge voltage to charge the battery quickly and safely. Once the battery is fully charged a somewhat lower voltage is applied to maintain the battery in a
fully charged state without excessive water loss. 3-stage charge improves battery performance and life while minimizing battery maintenance.
Bulk Charge
The SC30 will be in Bulk charge when battery voltage is below the Absorption Charge Voltage setpoint. During Bulk the SC30 delivers as much charge
current as possible to rapidly recharge the battery in an effort to drive battery voltage up to the Absorption Charge Voltage. During Bulk it is a combination of
battery size, state of charge and available charge current that determines battery voltage during, not the SC30.
Absorption Charge
When the battery recovers sufficient charge for battery voltage to rise to the Absorption Charge Voltage setpoint (factory set to 14.4V), charge current is
reduced as necessary to hold battery at the Absorption Voltage. The SC30 remains in Absorption until the battery is fully charged as determined by the SC30
holding the battery at the Absorption Charge Voltage continuously for the Absorption Charge Time period (factory set to 2 hours).
Float Charge
Once the battery is fully charged a somewhat lower Float Voltage (factory set to 13.2V) is applied to maintain the battery in a fully charged state
without excessive water loss. During Float a healthy fully charged lead-acid battery will draw about 0.1 – 0.2 amps per 100 amp-hours of battery capacity.
Charge Status LED’s
Shows present charge mode.
Setup Push-Button
Used with Display Select to
view or change charge
parameter settings.
Digital Display
May show battery voltage,
solar charge current, or solar
charge amp-hours. AMP
indicator be on if showing
solar charge current. Display
automatically dims at night.
Display Select push-button
Selects display mode. May
also be used to clear solar
charge amp-hours or
start/stop Equalize.
Front Panel heating
Panel serves as a heatsink
for power control devices,
may become quite warm
during normal operation.
Battery Level Graphic
Shows approximate battery
level vs. battery voltage.