MCM Electronics

Low Voltage Battery Cut-Off - 12/24V SelectableMCM Part #: 82-13990  |  Seco-larm Part #: ST-BD01Q

Low Voltage Battery Cut-Off - 12/24V Selectable 4 stars from 3 reviews.
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The Enforcer Low-Voltage Battery Cut-Off prevents deep discharge of backup batteries. Use it to save power for a backup battery on your security system. If there is a power failure this device will ensure that your backup battery remains powered and your security system won't go down.

Mfr.# ST-BD01Q

Product Description

  • Selectable 12/24VDC
  • Adjustable voltage cutoff and restore point
  • Master on/off switch
  • Green LED AC power indicator
  • Dual color DC LED indicator
  • Includes: Low Voltage Battery Cut-Off, battery lead, double-sided tape, and owner’s manual
  • Note: When not used with a control panel and backup battery, circuit requires that a momentary-on voltage be applied to the output terminals in order to latch or activate the relay switch
  • Mfr. #ST-BD01Q

Product Reviews

  • "Needs better description and instruction" by mattdm on 7/8/2013
    Overall: 4 out of 5

    I ordered this product believing that I can use this on a DC-only circuit without much complication. It did not work as expected; no LED light illuminated and the relay did not engage. I retraced the circuit to check everything and ensured the relay activates and the general circuitry is laid out properly (another person commented that he had to wire the battery to the output connectors). Long story short, everything appeared to be functional. Here's the catch: the circuit requires that a momentary-on voltage be applied to the output terminals in order to latch or activate the relay switch. Once the relay is activated, the momentary-voltage can be removed as the relay will hold-on until the input battery voltage drops below the cutoff voltage. This information is not found in the instructions.

  • "Great product that did what I needed it to do." by egadgetgeek on 7/25/2012
    Overall: 5 out of 5

    I purchased this product to fill a gap that was missing from a power supply I had purchased. The power supply had the feature of having a backup battery that it would keep charged then use if the AC power went out. It worked great except it would drain the battery below a safe level. This product worked great at keep the battery from being discharged too far. It was a simple hook up. I plan to put it inside the power supply when time allows.

  • "mislabeled connections?" by tmetro on 12/6/2011
    Overall: 3 out of 5

    This product either has a design flaw, mislabeled connections, or I don't understand the manufacturer's intended purpose.

    Presumably this device is intended to go between a backup battery and an alarm panel, where normally the alarm panel provides charging voltage to the battery, but in the event of a power failure, the panel draws current from the battery. This device is then supposed to detect when the battery voltage drops below a threshold and disconnect the battery to prevent deep discharging it.

    The circuit uses a relay (which you can hear engaging) to complete the circuit between the battery and the panel, and has an indicator LED to show when it is actively engaged. To test it out I attached a variable voltage power supply to the battery terminals (red and black wires), set it to about 12 VDC, and turned the "master switch" on. Nothing happened. No light, no relay. Varying the voltage made no difference.

    I found that if instead I attached the "battery" to the alarm panel side (faston terminals), the device seems to work as you'd expect. The relay engages. The LED illuminates. Voltage appears on the other connector (the "Battery" wires). When you drop the voltage below about 9 VDC the relay drops out, and no voltage appears on the battery wires.

    My first test scenario (voltage applied to only the battery terminals) should have emulated a power fail scenario. Given it only worked when wired in the opposite fashion, it would seem the connectors are mislabeled. Unless the circuit has some sort of a latching mechanism, where it needs to see voltage on the panel side in order to initially engage the relay, but if power is lost from the panel, it'll keep the relay engaged as long as there is adequate battery voltage. (I didn't test for that.) But if that's the case, the manufacturer failed to explain it, or specify that the device requires a specific power up sequence.

    It is also worth noting that although the device has an adjustable cut-off threshold, I found the lowest voltage it would keep the relay engaged at was 9 V. (Manufacturer specifies a range from 9 V to 10 V, or 19.2-20.3 V in 24V mode.)

    The circuit also has pass through connection for the AC power supply going to the alarm panel. One of the lines passes through one pole of the "Master Switch", and has a green LED hanging off it. It seems to serve little purpose, so I only verified through visual inspection that the AC connections were separated from the battery cut-off functionality and didn't test them.

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Package Specifications & Dimensions
Weight:0.14 lbs.
RoHS Comp:Yes
Warranty:90 days
Need to Return?
Length:3.37 in.
Width:3.25 in.
Height:1.87 in.
Shipping Information
Extra Shipping Charge:No
Drop Ship:No
Catalog Pages

MCM Cat 56, Page 494

Mfr. Info

Mfr. Name:Seco-larm
Mfr. Part Number:ST-BD01Q
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