LVD
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LVD currently used for the fridge power only - protects batteries from over discharge

For sale we have the REUK Programmable 12V Low Voltage Disconnect with Display.

This device is designed to protect a 12V battery or battery bank from being run down excessively and suffering permanent damage.

The output from this low voltage disconnect is rated to 1 Amp. This can be used to directly power lighting and other devices up to a total of 1 Amp, or can be used to energise a relay which in turn can switch much higher current levels. (see here for relay boards: http://www.reuk.co.uk/Relay-Boards.htm).

NEW - View our other ebay listings for a version of this device with a built in datalogger for monitoring the minimum, maximum, and average measured battery voltage.

The user can program the voltage below which the low voltage disconnect will engage (turning off the output and therefore disconnecting the loads to protect the battery), and also programme the voltage above which the output will turn back on again reconnecting the loads.
To ensure brief spikes and dips in voltage are ignored, the measured battery voltage must remain below the low voltage threshold for 10 seconds continuously before the disconnect engages. The voltage must subsequently remain above the high voltage threshold for 10 seconds continuously before the disconnect will be cancelled.

The LCD display unit is backlit and shows the measured battery voltage, the system status, and the user-programmed high and low voltage thresholds. The backlight is used to give a visual indication (by blinking) when the system state may be about to change.

PROGRAMMING INSTRUCTIONS
Connect the controller circuit board to the 12V battery and to the LCD display as shown in the connection diagram provided in this listing.

To programme in your voltage thresholds, press and hold the black button on the circuit board. The backlight on the display will turn off. If you keep holding the button for 3 seconds, the backlight will turn back on and the display will show PROGRAMMING MODE -RELEASE BUTTON-. You are now in programming mode, so release the button.

The display will now show Set Low Voltage 12.5 Volts. 12.5 Volts is the maximum value for the low voltage disconnect voltage. You now use the button to reduce this in 0.1 Volt steps until you get to your desired value – i.e. press the button six times to get down to 11.9V. Five seconds after the last time you press the button, whatever value is displayed will be stored in memory as your low voltage disconnect voltage. The screen will now show Low Voltage Saved XX.XV (where XX.X is the voltage you set).

After a couple of seconds the display will show Set High Voltage 12.0 Volts. 12.0V is the minimum value for the high voltage cancellation voltage. You now use the button to increase this in 0.1 Volt steps until you get to your desired value. Five seconds after the last time you press the button, whatever value is displayed will be stored in memory as your high voltage cancellation voltage. The screen will now show High Voltage Saved YY.YV (where YY.Y is the voltage you set).

Note that the high voltage threshold must be set to be at least 0.3V higher than the low voltage threshold. Therefore, if after going through the programming steps described above, this condition is not met, the screen will display HIGH V TOO LOW AUTO SET TO YY.Y where YY.Y will be 0.3V above whatever value you had set for the low voltage threshold.

The thresholds you programme in are stored in long term memory and so are NOT lost if/when you disconnect the device from the battery. Therefore you only need to go through these programming steps when you actually want to change the thresholds.

USING THE LOW VOLTAGE DISCONNECT
With programming out of the way, everything is very simple. If the voltage falls below the low voltage threshold, the backlight of the display will blink. The system status will change to LOW, but the output will remain on. If after ten seconds the battery voltage is still measured to be low, then the system status will change to OFF, the output will turn off, and the display backlight will stop blinking.

When the battery is recharged or recharging and exceeds the high voltage threshold, the system status will change to HIGH, the display backlight will start to blink, but the output will remain off. If after ten seconds, the battery voltage is still above the high voltage threshold, then the system status will change to ON, the output will turn on, and the backlight will stop blinking.

If when the device is first connected to the battery, the measured voltage is immediately found to be below the low voltage threshold, the device will start in the OFF position - i.e. output off, system status OFF.

FURTHER INFORMATION
If you have any questions about this low voltage disconnect the or if you are interested in a unit built in datalogger, or something for 24V battery systems etc, contact us via ebay or the REUK.co.uk website.


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