VictronConnect - MPPT Solar Charge Controllers

5. Programmable relay

In this section:
VC_Programmable_relay.png

A programmable relay switch is available on some SmartSolar models. The datasheet for your model will tell you whether or not it is available.

The relay offers three connections:

  1. NO (Normally Open)

  2. C (Common)

  3. NC (Normally Closed)

Relay state

Connection between

Switched ON

C and NO

Switched OFF

C and NC

The conditions for switching the relay depend on the relay mode setting, note that the conditions for switching over must be present for at least 10 seconds before the relay will change position.

Relay mode

  1. Relay always off. This option switches the relay OFF. It will disable the other relay options. Use this option if you do not plan to use the relay function.

  2. Panel voltage high. This option switches the relay ON when the panel voltage becomes too high. See Panel voltage high mode settings below.

  3. High temperature (Dimming). This option switches the relay ON when the charger output current is reduced due to high temperatures. Use this option to for example switch an external fan.

  4. Battery voltage Low. This option switches the relay in ON when the battery voltage falls too low, see Battery voltage Low settings below. This is the default setting when the relay function is active.

  5. Equalization active. This option switches the relay ON when the manual equalization mode is active.

  6. Error state. This option switches the relay ON when there is an error.

  7. Defrost option (Temp < -20 °C). This option switches the relay ON when the Charger temperature falls below -20 degrees Centigrade.

  8. Battery voltage high. This option switches the relay ON when the battery voltage is too high, see Battery voltage High settings below.

  9. Float or Storage state. This option switches the relay ON when the charger is in the float state.

  10. Day detection (Panels irradiated). This option switches the relay ON whilst the solar panels are providing energy (Day/Night detection).

Panel voltage High settings

  1. Panel high voltage. (User-defined Voltage)

  2. Clear panel high voltage. (User-defined Voltage)

This option switches the relay ON when the panel voltage rises above the chosen “Panel high voltage” setting, and switches the relay OFF when the panel voltage falls below the chosen “Clear panel high voltage” setting. Ensure, of course, that the “Panel high voltage” setting is greater than the “Clear panel high voltage” setting. These settings must never exceed the maximum voltage-rating allowed by your MPPT charger.

Battery voltage Low settings

  1. Battery low-voltage relay. (The default setting for this is 10.00V) (12V battery assumed)

  2. Clear battery low-voltage relay. (The default setting for this is 10.50V)

These settings, which can be user-defined, will cause the relay to switch ON when the battery voltage falls below the chosen “Battery low-voltage” setting; and will cause the relay to switch OFF when the battery voltage once again rises above the “Clear battery low-voltage” setting. Ensure, of course, that the “Battery low-voltage relay” setting is lower than the “Clear battery low-voltage relay” setting.

An application for this feature, for example, is to automatically disconnect a load in order to prevent a battery from becoming too deeply discharged.

Battery voltage High settings

  1. Battery high-voltage relay. (The default setting for this is 16.50V) (12V battery assumed)

  2. Clear battery high-voltage relay. (The default setting for this is 16.00V)

These settings, which can be user-defined, will cause the relay to switch ON when the battery voltage rises above the “Battery high-voltage relay” setting; and will cause the relay to switch OFF when the battery voltage drops below the “Clear battery high-voltage relay” setting. Ensure, of course, that the “Battery high-voltage relay” setting is greater than the “Clear battery high-voltage relay” setting.

An application for this feature, for example, is to disconnect a load in order to protect it from an over-voltage.

General settings

  1. Minimum closed time. (The default setting for this is 0 minutes)

This option sets a minimum-time for the ON condition to prevail once the relay has been switched ON.

An application for this feature, for example, is to set a minimum generator run-time.