Beware of Misinformation on public landscape lighting message forums

Beware of Misinformation on public landscape lighting message forums

By Mike Gambino

cluelessOnce again I am amazed at the poor and potentially damaging misinformation in regards to landscape lighting on public access message forums. One recent post titled 12V vs. 14V really made my blood boil because its truly the blind leading the blind. Here it is below with my comments in bold italics. The initial question was asked by a landscaper and the bulk of the answer comes not from a designer/installer but from a re seller of imported products to do it yourselfers and some misguided designer/installers. Obviously there are two agendas at play here. The reseller whose agenda is to sell products to everyone and anyone and doesn’t care if they know what they are doing or not. And my agenda which is to preserve the professional status of this industry and re-enforce the need to involve the help of professionals if the best result is what you are after. Things are certainly not as simple as this product reseller would like to make you believe.
Q-I have 4 50 watt fixtures. Would they be brighter hooked up to 14V instead of 12V?This question was posted by a landscaper which is really scary  as this is lighting 101 and a rudimentary piece of information that one must have before ever attempting to install landscape lighting.
A-If they are halogen/incandescent then yes they will be brighter but don’t do it.12v lamps are meant to be run between 10.5-12 volts. This is recycled old information that has no factual basis. 12 volt halogen lamps are designed to operate at or as close to 12 volts. A span of 1.5 volts between lamps on a project is totally unacceptable. This is so because brightness will be noticeably different, color shifts and lamp life is affected.  Once you go above 12volts their life span will drop dramatically. At 13 volts the life span will be ~50% and 14 volts ~25%. Additionally they will be outside their designed safety voltage range. (if below 10.5 volts they will not be burning hot enough and can give off a black soot that reduces life span as well). I don’t know what “soot” he is describing but when the halogen cycle does not occur due to low voltage the tungsten does not get deposited on the filament and a blackening of the capsule can occur as a result. What he doesn’t mention is the possibility of the glass capsule on the halogen lamp exploding when over voltaged.If they are 50v equivalent LEDs then the answer is no they will not be brighter. LEDs use constant current drivers. LEDs have a much wider operating range which varies depending on driver design. The range can be as big as 6-30 volts but is usually around 9 volts-18 volts.

 This is poor advice. 50v? I am assuming he meant 50 watts. You would be very hard pressed at this time to even find a 50 watt halogen replacement in LED for outdoor use in enclosed fixtures that has the same lumen specifications and lamp characteristics. This broad generalization of an answer does not even address dimmable LED lamps. Again the 12 v LED lamp was designed to optimally operate at 12 volts.  Dimmable LED’s will lose brightness as the voltage is reduced. Therefore the wide voltage span purported to be acceptable is absurd.  Furthermore it is way too early in the game to safely determine what affect operating LED’s at voltages other than 12 volts or close to it will have on their longevity.

Q-Thanks! Why do they make transformers that have the 14V option then? Wow, this is amazing as it shows a total lack of grasp of the concept of low voltage landscape lighting.
A-The 14 volt tap on a transformer compensates for voltage drop in the wire. Resistance in copper wire reduces voltage until it gets to the termination point.

 This is an excellent answer and it came from an experienced installer.

A- To clarify, the goal for halogen/incandescent is to get 10.5-12 volts at the fixture. As your cable run gets longer and/or you add more fixtures (load) onto the cable, the voltage drops. So if you start at 12 volts and have a long wire run, the voltage might only be say 9 volts at the end of the run. The higher voltage taps on the transformer (such as the 14 volt tap) enable you to boast the starting voltage so that you can get your desired 10.5-12 v even on longer runs or runs with more fixtures. Once again (see above) I disagree with the voltage span of acceptability. This statement paints with a super wide brush and doesn’t mention wiring techniques that would be required to accomplish small voltage spans like .5 volts which is the optimum acceptable range between all fixtures for best results in a halogen low voltage landscape lighting system.This is all old school now. If you switch to LEDs it’s a different ballgame that is much easier. LEDs can operate properly anywhere from 9-15 volts (for the most part) so you have more flexibility. Secondly they draw ~5X less power so the load is so much less– that means there is less voltage drop to begin with. With LEDs the layout is much less critical. You can generally just hook up to the 12 volt tap (or 15 volt tap if you have longer runs with lots of fixtures) and daisy chain all the fixtures on the same run. It doesnt matter whether the voltage at the fixture is 9 volts or 15 volts– the LED will perform the same output. Go LED its easier, faster, less maintenance, 80% more efficient. “Old school”? We haven’t installed a new halogen system in all of 2013 as its been all LED however halogen lighting is still very much a viable and energy economical choice for safe and effective landscape lighting systems. Again throwing the wide voltage spans around to make things seem simple, The next bit of advice about daisy chaining the installation is just plain irresponsible. Higher lumen low voltage LED’s are requiring more power , in some cases up to 12 watts. Voltage drop between the closer fixtures to the transformer on a cable run and the further ones will be significantly different. Daisy chaining is very seldom the choice of professionals. Most of all I resent this poor advice because it encourages and attempts to validate the practices of lazy and unskilled installers by breaking down any perception that this not easy work and not technically challenging just so he can make a sale of his products.

 

 

The most disappointing aspect of this all is the fact that at the time of this article being published, not one person has yet to set the record straight and challenge this information in that forum.

 

 

This landscape lighting blog is published by Mike Gambino of Gambino landscape lighting inc. all rights reserved. Mike is a professional landscape lighting system designer/ builder and has been designing, installing and maintaining landscape lighting systems for more than 20 years. Mike resides in the Los Angeles area with his wife and 2 sons. To visit his website go to www.gambinolighting.com . To inquire about hiring Mike please click here .Blog articles may be published with permission on other websites without editing or removing links.Facebook-ice

 

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