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View Full Version : It's amazing what you notice....


starry night
04-07-2011, 10:18 PM
It's amazing what you notice after you learn just a little.
I was doing an organic lawn feeding today at a bank I maintain. I hadn't really paid much attention before to their minimal landscape lighting -- a few halogen up-lights under trees.
But today I did a little inspection and found all the wiring just laying on the ground, some exposed. some under the mulch. Then I looked around, found the transformer, and took a peek. One run was fed into the 12V and the other run was fed into the 13V for no apparent reason. In fact, after looking around there was less wattage by lamp count on the run going into the 13V.
As you may know by other posts, I am a newcomer.
My findings were not astounding for you pros but it was interesting to me.

S&MLL
04-08-2011, 12:34 AM
Well there is good reason for that.... I'm sure the fixtures on the 13v tap were further away from the trans....


We use multi tap transformers to account for vd.
Posted via Mobile Device

starry night
04-08-2011, 08:20 AM
Well there is good reason for that.... I'm sure the fixtures on the 13v tap were further away from the trans....


We use multi tap transformers to account for vd.
Posted via Mobile Device

Maybe I'm just looking for trouble. But there were only 3 fixtures on that run and the farthest was 30 feet. I didn't take them apart to see the wattage but for their use it would not have been high.

I'm not trying to argue; just want to learn.

steveparrott
04-08-2011, 12:58 PM
Maybe I'm just looking for trouble. But there were only 3 fixtures on that run and the farthest was 30 feet. I didn't take them apart to see the wattage but for their use it would not have been high.

I'm not trying to argue; just want to learn.

You're probably right, even three 35w lamps at 30' would lose less than a volt. Since we shoot for about 11v at the lamp, the 12v tap would probably be best. Of course, some cheap transformers may drop excessive voltage under load. . .

To make these types of calculations, try out the CAST Lighting System Calculator (http://www.cast-lighting.com/support-installers/system-calculator-installers/).

David Gretzmier
04-08-2011, 04:25 PM
one thing I have learned is to expect the unexpected. finding voltages that are within spec and fixtures placed and aimed properly is actually rare around here.

S&MLL
04-09-2011, 08:11 PM
You're probably right, even three 35w lamps at 30' would lose less than a volt. Since we shoot for about 11v at the lamp, the 12v tap would probably be best. Of course, some cheap transformers may drop excessive voltage under load. . .

To make these types of calculations, try out the CAST Lighting System Calculator (http://www.cast-lighting.com/support-installers/system-calculator-installers/).

You shoot for 11v on a mr16? ..... Is that why your mr16s are rated for 10k hours :hammerhead:

No but seriously steve why so low?

David Gretzmier
04-09-2011, 09:54 PM
we used to spec between 10.5 and 11.5, but I kinda got slammed on here for being so low, so we went to shooting for 10.8 to 11.5. 11 is pretty close to perfect for good color and long bulb life.

I am sure this voltage conversation will seem quaint to LED guys, and it probably will seem silly in 10 years to all of us.

indylights
04-09-2011, 11:02 PM
I always shoot for between 10.9 and 11.2 on halogen. Great color, and the cool side of the optimum range helps extend lamp life.

Scott Maloney
Sunflower Landscapes

S&MLL
04-09-2011, 11:28 PM
Maybe I like mine a little less yellow or something. But I run 11.8-12.2 all day. But we relamp every 2 years. tomorrow I will fire up a mr at 10.5-11 ........ But I know im gonna hate the color

Classic Lighting
04-09-2011, 11:36 PM
I range Mr-16's 11-11.5. I've had fairly good luck with bulb life and color performance. But I guess to each his own.

David Gretzmier
04-10-2011, 09:07 PM
I relamp every year, I replace some here and there even going with 10.8 to 11.5. I can't imagine how fast bulbs would burn out at 12.2 as an option.

and 10.9 to 11.2 ? that is a tight tolerance, I can't even imagine it without a gambino trans.