Installation
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Battery Disconnect Module Controller
Instructions
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MidNite Solar Battery Disconnect Module – MNBDM
The Midnite Solar Battery Disconnect Module (MNBDM) is an optional circuit board which can be installed in most MidNite
Solar E-Panels. It is used in conjunction with one or more MNBH Disconnect switches and MidNite Solar disconnecting
combiners to remotely shutdown the system in emergencies. The MNBDM is controlled by the (MNBH) Birdhouse
Disconnect switch and disconnects the main batteries from the system in a similar manner as the disconnecting combiner
disconnects the PV array from the rest of the system. The trip signal for the MNBDMs and combiners is generated by the
MNBH Disconnect Panel. Control signals are provided to the target devices via a ruggedized 600V CAT-5 cable, which
connects all components in the system.
Installation
Select a dry protected location for the MNBDM, such as inside an E-Panel or other enclosed panel. The MNBDM must be
mounted on standoffs to provide open space behind the board to prevent shorting it to the enclosure.
Power and Circuit Breaker Connections
The MNBDM is powered from the main batteries (24 to 48 volt) and has terminals for connection to the E-Panel circuit
breaker, other MNBDMs, the disconnecting combiners and the MNBH Disconnect Panel. Connect the switched battery
positive (after the battery breaker) to TB1 pin 1 (+). Connect the battery negative to TB1 pin2 (-). Connect chassis ground
to the TB1 pin 3 (GND symbol).
Connect the red circuit breaker trip wire to TB2 pin 1 (+) and the black to TB2 pin 3 (-). Leave TB2 pin 2 open (middle).
System Connections
There can be up to four MNBDMs in the system. All system components are connected together with CAT-5 cable which
plugs into the two RJ-45 (Ethernet-style) connectors, J1 and J2. There is no difference between the two connectors. A
typical installation consisting of one MNBH Disconnect switch, one MNBDM and one disconnecting combiner would use
one of the RJ-45 jacks for connection to the MNBH switch and the other for connection to the combiner. Connect one to
the MNBH Disconnect switch, or to another MNBDM that connects to the MNBH Disconnect switch. Connect the other to
any downstream MNBDM units or combiners. A terminating connector is not required on the last MNBDM.
Operation
The MNBH Disconnect Panel must be energized and connected to an MNBDM before closing the battery circuit breaker
on the E-Panel. If you attempt to close the breaker without the MNBH on and the cable installed, the MNBDM will detect a
problem and trip the breaker within about 5 - 7 seconds. This is a fail-safe feature that requires the system to be intact and
working before energizing.
If the cable is properly installed the power will remain on and the system is now ready for operation. The MNBDM LED will
briefly blink (off) three times when power is first applied. This is normal and indicates that the board is working properly.
The system may be tested by pressing the button on the MNBH Disconnect Panel, but doing that will trip every combiner
and MNBDM in the system. To avoid this, a small test button is located on the front edge of the MNBDM board. Pressing
the test button only trips the one breaker in that panel. Note that there is 2 second delay after pressing the button before
the breaker trips.
IMPORTANT SAFETY INSTRUCTIONS
SAVE THESE INSTRUCTIONS
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THESE INSTRUCTIONS CONTAIN IMPORTANT SAFETY AND OPERATING INSTRUCTIONS FOR
THE
MNBDM BATTERY DISCONNECT MODULE.
If you do not fully understand any of the concepts, terminology, or hazards outlined in these instructions, please refer installation to a qualified dealer, electrician or
installer. These instructions are not meant to be a complete explanation of a renewable energy system. All installations must comply with national and local electrical
codes. Professional installation is recommended.
GENERAL PRECAUTIONS
:
WORKING WITH OR IN THE VICINITY OF A LEAD ACID BATTERY, SEALED OR VENTED IS DANGEROUS. VENTED
BATTERIES GENERATE EXPLOSIVE GASES DURING NORMAL OPERATION. FOR THIS REASON, IT IS VERY
IMPORTANT THAT BEFORE SERVICING EQUIPMENT IN THE VICINITY OF LEAD-ACID BATTERIES YOU REVIEW AND
FOLLOW THESE INSTRUCTIONS CAREFULLY.
If service or repair should become necessary, contact MidNite Solar Inc. Improper servicing may result in a risk of shock, fire or explosion. To reduce
these risks, disconnect all wiring before attempting any maintenance or cleaning. Turning off the inverter will not reduce these risks. Solar modules
produce power when exposed to light. When it is not possible to disconnect the power coming from the Photovoltaics by an external means such as a
combiner, cover the modules with an opaque material before servicing any connected equipment.
Do Not expose to rain or snow. NEVER attempt to charge a frozen battery.
Do not smoke around batteries.
When it is necessary to remove a battery, make sure that the battery bank disconnect breaker is in the off position and that the PV breakers, grid
breakers and any other sources of power to the inverter are in the off position. Then
remove the negative terminal from the battery first
.
To reduce risk of battery explosion follow these instructions and those published by the battery manufacturer as well as the manufacturer of any
additional equipment used in the vicinity of the batteries.
Avoid producing sparks in the vicinity of the batteries when using vented batteries. Provide ventilation to clear the area of explosive gases. Sealed AGM
and Gel batteries do not under normal conditions create explosive gases. Refer to the battery manufacturer's documentation. Be especially cautious
when using metal tools. Dropping a metal tool onto batteries can short circuit them. The resulting spark can lead to personal injury or damage to the
equipment. Provide ventilation to outdoors from the battery compartment when installing vented batteries such as golf cart T-1 05 batteries. The addition
of a spill tray is also a good idea.
Clean all battery terminals. Very high currents are drawn from the batteries; even a small amount of electrical resistance can result in overheating, poor
performance, premature failure or even fire.
Have plenty of fresh water and soap nearby in case battery acid contacts skin, clothing or eyes. Wear complete eye and clothing protection. Always
avoid touching eyes while working near batteries. If battery acid or battery terminal corrosion contacts skin or clothing, wash immediately with soap and
water. If acid enters the eyes, immediately flood with cool running water for at least 1 5 minutes and get medical attention immediately. Baking soda
neutralizes battery acid electrolyte. Keep a supply near the batteries
Do not work alone. Someone should be in the range of your voice or close enough to come to your aid when you work with or near electrical equipment.
Remove rings, bracelets, necklaces, watches etc. when working with batteries, photovoltaic modules or other electrical equipment. Power from an
illuminated photovoltaic array makes a very effective arc welder with dire consequences if one of the welded pieces is on your person.
To reduce the risk of injury, connect only deep cycle lead acid type rechargeable batteries. Other types of batteries may leak or burst, causing personal
injury or damage.
Wiring methods used shall be in accordance with the Canadian Electrical Code, Part I.
Wiring must be done in accordance with the National Electrical Code Article 690 ANSI/NFPA 70. Use Class 1 wiring methods for field wiring connections
to terminals of a Class 2 circuit. Use only 1 4-1 0 gauge AWM wire. Select the wire gauge used based on the protection provided by the circuit
breakers/fuses.
Overcurrent protection must be installed as part of the system installation. Refer to the wiring diagrams provided in
this manual for breaker/fuse/GFDI sizes and model numbers.
Use of attachments or accessories not approved by MidNite Solar could result in damage or injury.
Before making any connections verify that the circuit breakers are in the off position including the inverter breaker. Double check all wiring before
applying power.