Re: Landscape lighting bulbs burn out prematurely
Joseph Meehan
> We have Malibu landscape lighting and the bulbs burn out after only
> about two months of service. They are very bright compared to my
> neighbor's Malibu lights and he only replaces bulbs about once a year.
> When the landscapers installed our lights they did not use the wiring
> that came with the set. Instead, they used their own wiring which is a
> much larger gauge resulting in less voltage drop by the time the
> current reaches the lights. I am sure they thought they were doing me
> a favor, but their generosity appears to have worked against the life
> of the bulbs. Is there a simple solution to drop the voltage enough so
> these bulbs don't burn so hot? Would a standard light dimmer for 120
> VAC work to adjust the 12 VDC voltage?
Run them in to sets of series so each gets only half the voltage. You
also may want to check the voltage they are really getting with a good
meter. You may find over voltage.
--
Joseph Meehan
Dia duit
RickR
doesn't have anything to do with the burn-out.
Check a couple of things;
1. What is the rated life of your bulbs?
2. How long are you running them? Timer or photocell or both? If your
running them all night and your neighbor isn't your going to lose bulbs
(and money) faster.
3. As below, check your incoming voltage. Are you getting 115-120V?
4. Check your out going voltage from the transformer. Many transformers
have multiple taps to help overcome line losses. Check it at the
closest fixture. If its over 11.5V you may want to drop it down.
5. Do you like having brighter lights? If so you may want to just live
with it.
6!! Check for voltage spikes! This is probably your problem. A motor
starting up or some other electrical problem (loose neutral, large
factory near by) can give you a spike that will burn bulbs in a well
designed system. This is the number one cause of premature failure.
7. Check for overheating in the fixtures. Not usually a problem
outdoors but killer for lamps.
Putting a dimmer in *will* get you longer life.
1. Get a transformer rated dimmer!!!! You could lose both the dimmer
and the transformer and that will cost far more than the extra bulbs.
2. Put it in the 120V side.
RickR
Jeff Wisnia
> We have Malibu landscape lighting and the bulbs burn out after only
> about two months of service. They are very bright compared to my
> neighbor's Malibu lights and he only replaces bulbs about once a year.
> When the landscapers installed our lights they did not use the wiring
> that came with the set. Instead, they used their own wiring which is a
> much larger gauge resulting in less voltage drop by the time the
> current reaches the lights. I am sure they thought they were doing me
> a favor, but their generosity appears to have worked against the life
> of the bulbs. Is there a simple solution to drop the voltage enough so
> these bulbs don't burn so hot? Would a standard light dimmer for 120
> VAC work to adjust the 12 VDC voltage?
If you happen to have another transformer with a 120 volt primary and a
12 or 24 volt secondary lying around you could wire it up as an
autotransformer to subtract 12 or 24 volts from the 120 volt line and
use that reduced voltage as the supply voltage to the transformer
feeding the lights.
The added transformer's secondary current rating has to be at least as
large as the primary current the exixting transformer draws of course.
Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
"Truth exists; only falsehood has to be invented."
Pop
"Joseph Meehan" <sligojo...@hotmail.com> wrote in message
news:uKYnf.190540$tD4.1...@tornado.ohiordc.rr.com...
: Ike wrote:
: > We have Malibu landscape lighting and the bulbs burn out
after only
: > about two months of service. They are very bright compared to
my
: > neighbor's Malibu lights and he only replaces bulbs about
once a year.
: > When the landscapers installed our lights they did not use
the wiring
: > that came with the set. Instead, they used their own wiring
which is a
: > much larger gauge resulting in less voltage drop by the time
the
: > current reaches the lights. I am sure they thought they were
doing me
: > a favor, but their generosity appears to have worked against
the life
: > of the bulbs. Is there a simple solution to drop the voltage
enough so
: > these bulbs don't burn so hot? Would a standard light dimmer
for 120
: > VAC work to adjust the 12 VDC voltage?
not with a regular dimmer. For DC you'd need something
different, made for the application. Or, maybe the right
transformer? Does it have multiple taps? Did they yuse the
right ones? I would doubt an install would depend on the
resistance of wires to be done right - very unreliable way to
design anything.
:
: Run them in to sets of series so each gets only half the
: also may want to check the voltage they are really getting with
a good
: meter. You may find over voltage.
===> Uhh, in series, meaning half voltage for two of them, you'd
be lucky if the bulb even glowed visibly in the dark of night!
It required about 80% before you start to get usable light from
them.
Your dropped your teeth or something there!
Pop
:
: --
: Joseph Meehan
:
: Dia duit
:
:
Pop
"Jeff Wisnia" <jwi...@conversent.net> wrote in message
news:TeSdnXR8cp7...@conversent.net...
Where the hell did you go to school? There was no course on
common sense or safety, was there? Or, umm, more likely you're
"self" taught? Keep learning!
:
: --
w_tom
life expectancy loss. But long before trying to fix things,
first, you should be collecting facts. Locate the problem
before trying to fix anything. That means numbers and a
multimeter. What is the voltage at those 12 volts bulbs?
Those numbers will explain much. Furthermore, what is the
power source providing that 12 VDC? Is it regulated or just a
transformer and some diodes? Finally, what is the AC voltage
going into that power source.
Jeff Wisnia
If you knew anything about college education Pop, you'd recognize that
my sig line indicates I'm an MIT electrical engineering grad without my
screaming it out. (And FWIW I hold a masters in the same field from an
Ivy League school to boot.)
You not even know what an autotransformer is Pop, but I can tell you
that back in the '50s I installed at least ten of them ahead of TV sets
and expensive home audio equipment to reduce the overly high line
voltage present on the lower floors of a high rise apartment building in
Cambridge, Taxachusetts. They were wired eggsackly the way I described
in my post.
There was a lot of line drop in that building's wiring, and the owners
had played with the supply transformer taps so the upper floor's line
voltage wouldn't sag too low. That caused the voltage to be up around
135 volts on the lower floors ... The building's manager had a nice
little side business going. He was stocking and selling high voltage
light bulbs to the tenants on those floors. <G>
That high line voltage raised hell with the filaments in the vacuum tube
electronics of that era, just like it appears it might be doing with the
OP's light bulbs.
If you think you're right about decrying my advice Pop, let's hear you
tell us why you think it's unsafe if done in a workmanlike manner using
a transformer with adequate winding insulation ratings.
Otherwise, kindly STFU.
Happy Holidays,
Jeff
Norminn
> We have Malibu landscape lighting and the bulbs burn out after only
> about two months of service. They are very bright compared to my
> neighbor's Malibu lights and he only replaces bulbs about once a year.
> When the landscapers installed our lights they did not use the wiring
> that came with the set. Instead, they used their own wiring which is a
> much larger gauge resulting in less voltage drop by the time the
> current reaches the lights. I am sure they thought they were doing me
> a favor, but their generosity appears to have worked against the life
> of the bulbs. Is there a simple solution to drop the voltage enough so
> these bulbs don't burn so hot? Would a standard light dimmer for 120
> VAC work to adjust the 12 VDC voltage?
I don't know volts from ohms, but helped a friend shop for those dang
Malibus. We had to select the right total watts to fit the transformer,
as I recall. If a bulb burned out, it was supposed to be replaced
quickly or the remaining bulbs got too much. Is the transformer right
size for size/number of bulbs?
Roger Taylor
"Ike" <spamm...@spamminator.com> wrote in message
news:ifi0q1d7ebu511au8...@4ax.com...
> We have Malibu landscape lighting and the bulbs burn out after only
> about two months of service. They are very bright compared to my
> neighbor's Malibu lights and he only replaces bulbs about once a year.
> When the landscapers installed our lights they did not use the wiring
> that came with the set. Instead, they used their own wiring which is a
> much larger gauge resulting in less voltage drop by the time the
> current reaches the lights. I am sure they thought they were doing me
> a favor, but their generosity appears to have worked against the life
> of the bulbs. Is there a simple solution to drop the voltage enough so
> these bulbs don't burn so hot? Would a standard light dimmer for 120
> VAC work to adjust the 12 VDC voltage?
Some of the technical answers are indeed good advice, especially the ones
advocating measuring voltage at key points from transformer to light
sockets. I have had a cheapo 12v malibu system for 8 years, with 10 lights
on the string. Over that time, only one of the ten has blown. There is
likely a serious overvoltage on your system, or you have been using the
wrong bulbs. Check to see that they are rated at 11-12 v.
Mark Lloyd
wrote:
>We have Malibu landscape lighting and the bulbs burn out after only
>about two months of service. They are very bright compared to my
>neighbor's Malibu lights and he only replaces bulbs about once a year.
>When the landscapers installed our lights they did not use the wiring
>that came with the set. Instead, they used their own wiring which is a
>much larger gauge resulting in less voltage drop by the time the
>current reaches the lights. I am sure they thought they were doing me
>a favor, but their generosity appears to have worked against the life
>of the bulbs. Is there a simple solution to drop the voltage enough so
>these bulbs don't burn so hot? Would a standard light dimmer for 120
>VAC work to adjust the 12 VDC voltage?
The voltage is probably 12VAC not 12VDC. Rectifying it would add to
the cost of the power supply unit, with no benefit. Incandescent
lights work just as well on either AC or DC.
A dimmer won't work on 12VDC, but it MIGHT work on 12VAC.
One thing you might do is install a diode (half wave rectifier) in the
line to get half power. Make sure it can handle the current. I've done
that before, to make lights dimmer.
--
11 days until the winter solstice celebration
Mark Lloyd
http://notstupid.laughingsquid.com
"Democracy is two wolves and a lamb voting on what
to have for lunch. Liberty is a well armed lamb
contesting the vote." - Benjamin Franklin
mm
wrote:
>We have Malibu landscape lighting and the bulbs burn out after only
>about two months of service. They are very bright compared to my
>neighbor's Malibu lights and he only replaces bulbs about once a year.
>When the landscapers installed our lights they did not use the wiring
>that came with the set. Instead, they used their own wiring which is a
>much larger gauge resulting in less voltage drop by the time the
>current reaches the lights.
Bigger wires have advantages, but I don't think there should be any
measureable voltage drop even with your neighbor's smaller wires.
Your neighbor's certainly wouldn't have been designed to work that
way.
>I am sure they thought they were doing me
>a favor, but their generosity appears to have worked against the life
>of the bulbs. Is there a simple solution to drop the voltage enough so
>these bulbs don't burn so hot? Would a standard light dimmer for 120
>VAC work to adjust the 12 VDC voltage?
Remove NOPSAM to email me. Please let
me know if you have posted also.
Jmagerl
caused by bugs building nests in them. Mine was caused by ants. I doubt that
thats it though just because you say the lights are noticably brighter. You
really do need a voltmeter to measure the AC voltage at the bulbs.
"Ike" <spamm...@spamminator.com> wrote in message
news:ifi0q1d7ebu511au8...@4ax.com...
> We have Malibu landscape lighting and the bulbs burn out after only
> about two months of service. They are very bright compared to my
> neighbor's Malibu lights and he only replaces bulbs about once a year.
> When the landscapers installed our lights they did not use the wiring
> that came with the set. Instead, they used their own wiring which is a
> much larger gauge resulting in less voltage drop by the time the
> current reaches the lights. I am sure they thought they were doing me
w_tom
example, voltage at 12.2 may shorten life expectancy by 50%
compared to a voltage of 11.8. Little voltage increase can to
cause a significant reduction in bulb life expectancy.
Important here is the 120 VAC voltage. What is that - to
three digits?
Reducing 12.0 volts to about 11.0 volts will increase bulb
life expectancy by a factor of three times.
Voltage is also how one can change bulb life expectancy.
One important factor - how many amps are being drawn from the
transformer. A two digit number is good for this. A device
that drops 12 volts by say 0.3 volts would consume how much
power? A calculation necessary before lowering voltage on the
12 volt side. Even a couple of diodes placed reversed and in
parallel on transformer output would limit voltage from 12.0
volts to about 11.3 volts. But 0.7 volts times that ballpark
current is how many watts - to estimate how hot those diodes
may become.
The answer of 115 to 120 volts tells little. What is that
number accurate to three digits. And how does it vary? Does
line voltage increase to 126 volts?
Voltage spikes would have little to do with bulb failure.
Regular incandescent dimmer must be on the 120 VAC side of
transformer.
BTW transformer output voltage drops as load approaches what
the transformer is constructed for. IOW a transformer that is
too large will output much higher voltage than intended for
full load. How much current is being drawn and how large is
the transformer rated?
Ike wrote:
> On 14 Dec 2005 10:11:37 -0800 "RickR" <in...@luminousviews.com> wrote :
>> ...
>> Check a couple of things;
>> 1. What is the rated life of your bulbs?
>
> 2000 hours and they are rated for 12 volts.
>
>> 2. How long are you running them? ...
>
> 5 to 8 hours per night, depending upon the time of year. This means I
> should be replacing them about once per year. The first bulb in the
> set will burn out in as little as two weeks and will last as long as
> two months.
>
>> 3. As below, check your incoming voltage. Are you getting 115-120V?
>
> Yes.
>
>> 4. Check your out going voltage from the transformer. ...
>
> I am getting 12 VAC on the output side, plus or minus a few
> hundreds of a volt. It was my error to think it was 12 VDC.
>
>> 5. Do you like having brighter lights? ...
>
> Yes, but not at the expense of such short bulb life.
>
>> 6!! Check for voltage spikes! This is probably your problem. ...
>
> Unknown if I have spikes.
>
>> 7. Check for overheating in the fixtures. Not usually a problem
>> outdoors but killer for lamps.
>
> The transformers are well ventilated inside our garage.
>
>> Putting a dimmer in *will* get you longer life. ...
>
> I tried putting a regular incandescent dimmer on the 12 VAC side but
> the lights did not work at all. Oh well, it only cost $5 for the
> dimmer to try it out.
> ...