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APPLICATIONS

Lighting applications include bus stop shelters, security, hazard signs, billboard and advertising signs, landscape, warning beacons, parks, campsites, roadside rest stops, walkways, street and parking lot lamps, etc.

DESCRIPTION

The SLC92 is designed specifically for photovoltaic (PV) powered lighting systems. The SLC92 combines the functions of a charge controller, a nighttime sensor, daytime sensor, an on/off timer, and a low voltage load disconnect, into a single solid state circuit. The SLC92 circuitry improves reliability, reduces system assembly time and testing, and facilitates troubleshooting and repair in the field.

STANDARD FEATURES

• Charge controller with series linear, constant voltage charge regulation

• PV array used for night and daytime detection

• No seasonal adjustments required

• First timer: instant-on, to 3.5-hour delay after nighttime detection

• Second timer: turns lights off and is adjustable from 0.5 to 15.5 hours

• Models available in 12 and 24 Vdc; 1 to 30 amps

• Field-adjustable float and low voltage load disconnect set points

• Solid state relay for load control

• Manually initiated controller test

• Temperature compensated float charge at 5.14mV/°C/cell

• Lightning protection on array input, battery input, and negative to ground

• Protectively coated for harsh and corrosive environments

OPERATION

During the day, the SLC92 efficiently regulates the battery charging. At early evening, when there is insufficient sunlight for battery charging, a timer is initiated. After a field-adjustable time (up to 3.5 hours) has elapsed, the light(s) are automatically turned on. Once the light(s) have turned on, a second field-adjustable timer is activated to automatically turn the lights off.  At sunrise, the daytime detect will override the timer and automatically turn off the lights. These features are convenient for cloudy weather and seasonal changes.

The timers save energy and allow you to maximize the light output during the hours when it is required most. The timers and efficient voltage regulation circuit reduces your system cost by minimizing PV array and battery requirements. To simplify simplify field testing of the controller and maintenance of the system, there is a manually actuated test for the controller’s on-board timers, solid state relay, lamp, and ballast.

The SLC92 is neither a switching- nor shunt-type regulator. The MOSFETs are used as variable resistors for precision voltage and current control. The float voltage is field-adjustable by an 18-turn potentiometer. This method of regulation has several advantages:

1. As the battery approaches its full charge condition, the charging current tapers to zero.
2. Because of the low resistance of the MOSFETs, the forward voltage drop through the SLC92 is extremely small, allowing the maximum amount of current to flow into the battery when required.
3. The SLC92’s efficient electronic circuitry reduces the PV array size, which can lower overall system cost.
4. Because of the low resistance of the MOSFET's, the forward voltage drop through the SLC92 is extremely small, allowing the maximum amount of current to flow into the battery when required.
5. The SLC92's efficient electronic circuitry reduces the PV array size, which can lower overall system cost.

To protect the battery against deep discharges which will shorten the battery life, the SLC92 will automatically turn off the lights at low battery voltages.

The SLC92 uses a low resistance, solid state relay to disconnect the light(s). Unlike an electromechanical relay, the solid state relay requires virtually no energy when energized. For small PV systems this can result in a considerable energy savings, thereby reducing system cost. Because there are no moving relay parts or contacts to wear, reliability is improved.

SLC92s, with array current ratings of 1 to 4 amps have 3 amp solid state load relays. SLC92s with ratings of 7 to 30 amps have 12 amp solid state load relays.

Over-Temperature Shutdown
Recommended for applications requiring charging currents greater than 7 amps. This is a safety feature that automatically reduces charging current should the charging MOSFETs get too hot due to poor installation or field abuse.

Factory Calibration
Though the float and LVD set points are field-adjustable, factory calibrated units can be specified with orders.

SPECIFICATIONS

 Solar Lighting Controller Assembly Model Identification

Custom controllers are available for higher voltage, larger currents, and longer sensor wires.