Low Voltage disconnect

freddieoliveras
freddieoliveras Registered Users Posts: 33 ✭✭
Hi, does anyone know a good affordable (less than $120) LVD ( Low Voltage disconnect) module?

Comments

  • Ampster
    Ampster Registered Users Posts: 174 ✭✭✭
    edited September 2019 #2
    It probably depends on the voltage and Amperage. I have cobbled some together from programmable voltage meters ($30) and higher amperage relays or contactors.
    For 12 volts, Elk make a simple device for alarm panels.
    8 kW Enphase micros AC coupled to a SolArk 12K
  • NANOcontrol
    NANOcontrol Registered Users Posts: 260 ✭✭✭
    There are many in the under $20 range <100V.  The real question is what do you want to disconnect.  What they send a signal to can be expensive. What voltage and amps?
  • freddieoliveras
    freddieoliveras Registered Users Posts: 33 ✭✭
    I need it for a 48V battery bank and want to activate a relay
  • Ampster
    Ampster Registered Users Posts: 174 ✭✭✭
    8 kW Enphase micros AC coupled to a SolArk 12K
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    I need it for a 48V battery bank and want to activate a relay
    So, to clarify, you already have a relay or contactor capable of safely disconnecting the max possible current flowing from the bank to the connected load?

    If so, charge controllers often include aux ports which can send a relay trigger signal (typically 12v)  based on various conditions, including low voltage.  The trigger is generally very low current, just enough to activate the relay coil. If charge controller or whatever aux output isn't available, there are lots of other pretty cheap ways of sending the trigger.

    The load side of the relay has to be rated to disconnect the load current though, which is where it can get expensive.  Contactors capable of disconnecting 48vdc safely and repeatedly at higher amperages can get spendy.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • freddieoliveras
    freddieoliveras Registered Users Posts: 33 ✭✭
    Actually I have an Outback FlexMax and a MATE, the MATE has AGS (automatic start generator) but I have been trying for a few months with Outback support to male it work, but brother we can’t make it work, so I’m looking for a second plan.
    Some inverters also have a Low Battery CutOff but mine does not.
    This one seen pretty nice
    https://4thdsolar.com/products/battery-monitoring-system-thornwave