New LVD wiring question

Discussion in 'General Questions' started by timber, Nov 17, 2010.

  1. timber

    timber WindyNation Engineer

    Hi Windy,

    I see that you now have the LVD in your Products listings.
    You mentioned previously that you thought the LVD could be configured to "switch ON" during a low voltage situation.
    I'm interested in turning on a grid powered battery charger if my battery voltage drops to an unhealthy level (10.5V is fine).
    I checked out the WindyNation’s LVD 12V & 24V Owner's Manual and think I can see how I would set up a circuit to do this but wanted to be sure.
    The last wiring diagram in the Owner's Manual shows an Optional Low Voltage Signal Connection using the blue wire.

    The relay I am thinking about using is the Opto 22 Solid State Relay.
    The Signal Pick-up Voltage of this relay is rated for 3-32VDC, Nominal AC line voltage is 120VAC.

    It looks to me like I can hook the blue wire to one of the signal leads (or terminals) of the Solid State Relay and connect the other signal terminal to 12VDC battery positive which in turn will turn on my battery charger (15A Iota AGM charger) when battery voltage drops to 10.5VDC. Does this sound correct to you?

    The reason I am asking for clarity is that the LVD manual indicates that the blue lead "can be used to switch an external device" but doesn't indicate whether it switches the device ON or if it switches it OFF. (I'm assuming ON but not sure.)

    Thanks for any clarification on this that you can provide.

  2. windyguru

    windyguru WindyNation Expert

    Hi Timber,

    I talked with John and he said the relay you are proposing to use is a perfect choice.

    Everything you wrote is correct and, yes, the blue wire will turn the external device "on". If you have more questions, just post them here and I will try to answer them.
  3. timber

    timber WindyNation Engineer

    Thanx Windy!

    It looked like that was the case but I wanted to get a good picture in my mind and confirmation that it should work.
    Thanks for checking with John on this, it's appreciated.

    I'll be getting one of the LVDs after I get the system set up with off-grid charging.
    Using the LVD will provide good back-up protection for my AGM batteries during low wind/ cloudy conditions.
    Batteries are expensive, it's nice to have that automated. I'll post on the incorporation of the LVD as I get that set up so others can potentially do this if desired.

    I can see another use for an LVD as well. Using the disconnect circuit (white wire, I believe) I could de-activate a (40A?) relay to disconnect my Inverter under low voltage conditions. On second thought, I'd better go back to the manual to see what amperage the disconnect circuit is designed for.
    I hate it when I let the blue smoke out of new toys ... :roll:

  4. timber

    timber WindyNation Engineer

    Hi Windy,

    I went ahead and ordered your new LVD and the Opto 22 relay discussed above.

    I hate to enter grid power into the equation but it's a necessary evil to insure that my AGMs are well maintained.
    Not having to constantly monitor and manually switch on the charger will be a great addition to the system.
    Thanks for reviewing this particular application, your great and ongoing service is appreciated.

  5. timber

    timber WindyNation Engineer

    ANOTHER ... LVD wiring question

    Hi Josh,

    I looked over the LVD manual and didn't see a recommended fuse size for the RED, power wire or the BLUE signal wire.
    I assume they would need to be a pretty low amperage to protect the LVD, internal circuit but I'm not sure what would be appropriate.

    Would a 1A, inline fuse be a good choice for both of these?

    Thank you for any information that you can provide.
    I won't be using the disconnect, Yellow or White wires for this application.

    I did see that the manual indicates that the Low Voltage Protection is adjustable, that could be very helpful in dialing-in my grid powered charger cut-in/ cut-out for optimum (AGM) battery protection.


    (aka timber)
  6. windyguru

    windyguru WindyNation Expert

    I am nearly certain a 1 amp in-line fuse will be good but I will double check with John tomorrow.

    I already had one person ask about the voltage being adjustable and, well, it is not really adjustable. John can customize the voltage for an extra charge so I guess that is what he meant by adjustable. I am just going to remove that adjustable part tomorrow from the instructions.
  7. timber

    timber WindyNation Engineer


    BTW, I received the LVD this morning and ordered it after work hours on Friday ... someone must be working overtime ... that was very QUICK!
    Not a problem on the adjustment, probably a good idea to remove the text though.
    I'll wait on the fuses till I hear back ... thanks for all!

  8. windyguru

    windyguru WindyNation Expert


    They both get 1 amp fuses. The red wire from the LVD gets a 1 amp fuse.

    The 12 volt side of the relay you use to switch "on" your battery charger also gets its own 1 amp fuse. John says that will be the other side of your relay connection (not the blue wire).

    If that does not make sense, let me know and I can get more information or a wiring diagram to you. - Josh
  9. timber

    timber WindyNation Engineer


    All makes perfect sense, just like the wiring diagram for the sensor circuit on the LVD (last diagram in LVD manual).
    I stated incorrectly that it was the blue wire, I'll place it on the battery side of the relay as shown there.
    Thanks for checking, it's appreciated!


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