PV Controllers

BR5 PV Controller & Voltage Regulator
The BR5 is a combined 12V solar controller and voltage regulator (DC/DC converter). It is mounted on a single sided PCB and uses conventional leaded components which are shielded by an aluminium cover plate. The latter also acts as a heat sink. Both the controller’s upper set-point and the regulator’s output voltage are adjustable. A status indicating LED is mounted on the board as well as a system test switch. All connections are made via a 6-way terminal block (solar +/-, battery +/-, load +/-).

Dimensions

90 (L) x 45 (W) x 22* (H) mm * This does not include the pillar supports shown in the photograph. 55g nett weight

Solar (PV) Controller

This is a shunt regulator designed to limit the maximum voltage to which a lead acid battery can be driven when on charge from a photovoltaic (solar) module or array. It is a solid state device for use with photovoltaic modules having a peak current not exceeding 6A. The unit has very low power consumption (< 1mA) and features a single green, status indicating LED, which is illuminated when the battery voltage has reached the set-point and the module output is being shunted. The circuit for the regulator comprises three main elements, a voltage comparator, a semiconductor switch and a blocking diode. The purpose of these elements is as follows:

Voltage Comparator

The battery voltage is constantly compared with an internal reference level and when it reaches the set-point (factory set at 14.6V @ 20°C) the semiconductor switch is triggered. The reference set-point voltage is automatically adjusted upwards at lower temperatures and downwards at higher ones. (Coefficient is -20mV/°C)

Semiconductor Switch

When triggered the switch shunts the solar module/array, diverting its output away from the battery. When the battery voltage has decayed by 1.5V the module/array output is reconnected to the battery.

Blocking Diode

This is an electronic non-return valve and serves two purposes. Firstly it ensures the battery cannot discharge through the module/array at night and secondly that the battery is not shorted when the regulator shunts the module/array.

Voltage Regulator

This provides a stable voltage at up to 700mA and is adjustable from 3.75V to 11.6V (assuming 12V at system battery terminals). The dropout voltage is very low at 0.4V as is the current consumption (< 50µA).

System test Switch

This allows all system elements to be temporarily isolated from each other for easier condition analysis as shown in the table.