CirKits.com LVD1-a1 Low Voltage Disconnect Alignment Instructions Work with the board mounted on a non-conductive surface, or mount the board permanently to a metal plate using spacers. You will need a 0-15VDC variable voltage power source such as a lab supply, a volt meter and the assembled Low Voltage Disconnect circuit board. Make sure to connect the power source with the correct polarity. CAUTION: the first time the board is connected to the power source, it is advisable to make a brief connection to be sure that there are no high current shorts from the soldering job. Rechargeable batteries have the ability to produce large amounts of current, short circuiting batteries can cause fires. Remove metal jewelry when working with batteries. Keep loose wire and metal away from the circuitry. The customer assumes all liability for any damages. Never apply more than 18V to the LVD1 board or damage will result. It is recommended that you use a red positive (+) wire and a black negative (-) wire for the battery connections. The potentiometers have a full range of 25 turns, they make a faint clicking sound when they are at the endpoints. Before aligning the circuit, first decide which off voltage, on voltage and low voltage detector settings you wish to use. Remember that a battery's voltage will tend to rise after a load is disconnected, so the on and off settings will need to be a few volts apart or the load may oscillate on and off when the battery is depleted. A good test is to connect the load directly to the battery and run the battery down to a suitable shutoff point (typically 10-11V for a lead-acid battery). Disconnect the load and see where the battery's voltage rises to, the On point should be set higher than that voltage. []Connect the board's BAT - terminal to the DC supply's - terminal. []Connect the board's BAT + terminal to the DC supply's + terminal. []Connect a volt meter across the DC supply's output terminals or refer to the supply's voltage meter if it has one. []Install the shorting block on jumper JP1 to enable the calibration LEDs, LED2 and LED3. []Turn both toggle switches to the On (right) side. []Set the variable voltage DC power supply to the off voltage, 11V DC is a typical value. []Turn the Off setpoint potentiometer RV1 clockwise until LED3 turns on, adjust RV1 back and forth to zero in on this point. []Set the variable voltage DC power supply to the on voltage, 12.5V DC is a typical value. []Turn the On setpoint potentiometer RV3 clockwise until LED2 turns off, adjust RV1 back and forth to zero in on this point. []Set the variable voltage DC power supply to the Low Voltage warning point, 11.3V DC is a typical value. The Low Voltage warning point should be beween the Off and On setpoints. []Turn the Low Voltage setpoint potentiometer RV2 clockwise until LED4 turns on. The Low Voltage detector has hysteresis (resistance to change states) so adjust RV2 slowly from the point where LED4 is off to where LED4 just turns on. []Verify the operation of the LVD1 circuit by adjusting the variable supply between 0V and 15V. LED1 should flip-flop on and off as LED2 and LED3 turn on. LED4 should turn on as the voltage is lowered, it will stay on until the voltage is around 3 Volts. If S2 is in the manual position (middle), LED1 will turn off and stay off until S2 is temporarily switched to the left, even if the battery voltage is above the On setpoint. []Optionally remove the shorting block on jumper JP1 to minimize the LVD1 board's power consumption. []The alignment of the LVD1 board is now complete. LVD1 Board Mounting: The LVD1 should be permanently mounted in a metal or high temperature plastic box to prevent short circuits and the resulting fire hazard. A good enclosure for the LVD1 is a box with a clear plexiglass top, holes can be drilled in the sides of the box for the switches and wiring. The LEDs can be viewed through the plexiglass. The LVD1 should be mounted to the enclosure with four 4-40 x 1/2" screws and 1/4" long spacers. Do not connect permanent power to the LVD1 until it is screwed into the box and the box is screwed shut. Be sure to allow sufficient ventilation if the LVD1 is to be used at or near the full 20 amp current capacity. Cabling to the LVD1 should be securely clamped to the enclosure. LVD1 Board Connection: Crimp-on spade lugs are the preferred way to terminate the DC supply and load wires. The minimum recommended wire gauge for 20 amp operation is #12, stranded wire is easier to work with than solid wire. The LVD1 can be permanently connected to a 12VDC power source such as a solar-charged lead acid, NiCd or NiMH battery or a 12V DC power supply. If the power source is a long distance from the LVD1, a 15 amp fuse should be put near the power source to protect the wire against shorts. LVD1 Board Operation: -The battery or power source should be connected to the - BAT + terminals on connector CN1. -The load should be connected to the - LOAD + terminals on connector CN1. Load current should not exceed 15 Amps or the fuse F1 will blow. -A computer or other circuit can be connected to connector CN2 for detecting low voltage prior to power disconnection. CN2 pin 1 is ground, pin 3 is +5V and pin 2 is the active-low low voltage detection signal. -If the power switch S1 is off, LED1 and the load will always be off. -If the power switch S1 is on and S2 is switched to Auto-On, LED1 and the load will turn on and off with varying battery voltage. -If the power switch S1 is on and S2 is switched to Manual (center), LED1 and the load will stay on until the battery voltage drops below the Off setpoint. After the battery voltage rises above the On setpoint, it will be necessary to push S2 to the left to manually activate LED1 and the load.