Need voltage drop help

Discussion in 'Landscape Lighting' started by Rainman7, Apr 14, 2012.

  1. Rainman7

    Rainman7 LawnSite Senior Member
    from NY
    Posts: 288

    A few years back I installed a unique 24v system on a property due to distance issues. It has been working very well except now the cust wants some lighting down his 400' driveway. I want to use led's which operate between 10 & 17 volts. I have a spare branch off a hub to the furthest point we have lit which I connected it to thinking the voltage drop matpy take care of it but it doesn't...only goes down to 21v. Anyone have an idea how I can bring it down?
  2. Lite4

    Lite4 LawnSite Gold Member
    Posts: 3,113

  3. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Posts: 4,102

    I would recommend that you ensure the long term operating voltage of those LEDs falls into the middle of their range and not at the top of the range.

    This is the first thing I have heard about Unique's 24V "system" in some time. I guess Nate had it wrong when he predicted that 'this LED thing isn't going to go anywhere'. (paraphrasing)

    In the long run, I think it would be better to discuss a complete switch over and update to LEDs for your client. This would require a new transformer and a bunch of retrofit LED lamps or new LED fixtures. Having a mixture of 24V lamps and LED product in the same system is not an ideal long term solution.
  4. steveparrott

    steveparrott Sponsor
    Posts: 1,196

    I wouldn't recommend any of the voltage regulator devices that operate at the fixture - they have a troubled history.

    The CAST LED Bullet and Tree Light operate up to 28.8V.
  5. GreenLight

    GreenLight LawnSite Senior Member
    Posts: 466

    Have you already built this run yet and how many leds/watts are you ultimately going to be pulling off the hub branch?

    If you are at 21 volts, empty load from the hub output and you still need to run somewhere from 100-200 feet of wire with 6-8 new leds averaging 3-5 watts per, you could simply use much lower guage wire to exit the hub. For instance, if you came out with 16-18 gauge wire and connected a total of 40-50 watts over the span of a few hundred feet, you can dramatically drop your voltage from that point. You would probably have to avoid daisy chaining because the first few lights would probably still run to hot, but if you made hybrid Tee's that carry multiple lights from a single junction point it's quite feasible.
  6. steveparrott

    steveparrott Sponsor
    Posts: 1,196

    It would only take a few burnouts of the incandescent lamps to bring your voltage too high. The risk of over-voltage at the LED's (and subsequent failed LED's) is too great in all these approaches. Either spec LED fixtures that will handle the voltage or run a new line to the transformer.
  7. GreenLight

    GreenLight LawnSite Senior Member
    Posts: 466

    I agree, it's definitely less than conventional and would have a downside if you had unmonitored halogen burnouts.
  8. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Posts: 4,102

    Or you could install a new, conventional transformer and replace all of the 24V lamps with LED lamps. This solution would be much less expensive than replacing all of the fixtures with LED fixtures that have relatively high input voltages.
  9. irrig8r

    irrig8r LawnSite Platinum Member
    Posts: 4,535

    Well, I'm not going to take sides while the two forum sponsors battle this one out... except to say that I think Steve's solution might work well for you in your situation. It seems that the folks at CAST saw a niche (systems with higher voltage output transformers that CAST, Unique and even Vista were pushing just a few short years ago) and found a way to fill it.

    Either way, run the numbers and see which is the most economical or most profitable, depending on your relationship with your client.
  10. S&MLL

    S&MLL LawnSite Senior Member
    Posts: 751

    Great advice.
    Only thing i could add is watch for color temps. I have never even seen a 24volt install but at what volt do these lamps run warm. If 21 volts is similar to 10.5 on a 12 casts led might appear a bit on the hot side.
    Posted via Mobile Device

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