View Full Version : Light bulbs not lasting... Help

East Coast Lawn Choppers
08-21-2009, 03:57 PM
We did a patio for a customer. They had a transformer that they bought somewhere. We put lights in the patio (that match the cobble) , and a few step lights. Then an electrician came in and put lights all over the place. Now my question....
Are AC and DC and DC bulbs interchangable and to what extent. A few of the lights had halogen or xenon bulbs, the patio lights have what looks like a normal incadesent bulb (like a large 194 style). The step lights use a 194 sylvania which is the same as what a car takes 12v dc. No LED's in the circuit....
The transformer is a 12v AC 1200w with a few cuircuts and a eye and also a programable timer. The problem we had is the 194 12v bulbs all blew out in less than a year. Then the xenon or halogen bulbs got so hot the one melted the socket... I measured the voltage with the whole circuit energized and it is right at 12V AC. Almost the same right at the bulbs because we ran 12 ga wire to all of the lights.
As far as my background I have an electronics degree and spent ten years working on lasers that cut ceramic along with all other machinery, but never had to mess with low voltage lighting...
I know this probably sounds dumb but....

08-21-2009, 04:03 PM
where are you measuring the voltage at ? How many watts are on the 12ga circuit ? Something tells me your using the wrong lamps or over volted. This is what happens when you supply some stuff... the electrician supplies some stuff and the homeowner supplies some stuff.

Could also be some of the lights were hooked up in series vs a more suitible method ? If thats the case your lamps could esentially be working as fuses.

East Coast Lawn Choppers
08-21-2009, 04:19 PM
I measured the 12v at the transformer and it is the same at the bulbs. The wiring is only 10-20 feet long and it is 12 ga. wire. They are all in parallel, one circuit has 3 12v 3.9w bulbs and 2 12v 6w bulbs all in parallel in on a 15' 12 ga. then the second has 4 12v xenon bulbs in parallel on a 12 ga. wire they are spaced at 4' 8' 12' and 16' on the wire. The third circuit has 8 12v 6w bulbs on a 12 ga wire they are wired in parallel 1st at 8' 2nd at 12' third at 16' 4th about 20' they each have two bulbs in each light.
They shouldn't be able to pull more current then they need should they ? If you put one bulb on a 1200w transformer it won't pull 1200w thru the one bulb correct ?
Hope this info helps...

08-21-2009, 05:08 PM
No it will not pull more than it "needs" IF it is wired properly.

You said you have 4 lamps at 12v... what is the wattage tho. How are you checking the voltage at the lamps ? Under load or at no load ? Sounds to me like you have crappy lamps and since its so close to the transformer and such a small wattage lamp you might be over volted.

You say you have 12v... Are you SURE you dont have 12.5 or 12.8 etc... If so your over volted thus causing permature failures in the system. Typically we try to run in the low to mid 11v but alot of guys say 10.8 to 12v is acceptable. I never push the 12v envelope and stick to mid 11's and my lamps last 2 years or more.

NOW... it seems to me and in my experience the smaller the wattage the more delicate the lamp is. This is why I run my 10w mr16 lamps at a lower voltage. This is the only way I have found to get them to last longer.

If your over volted and there is no tap lower on the trans to lower the voltage you would need to either use a dimmer on the 120v side (ASSUMING THE TRANS IS DIMMABLE) or... increase the load/wire lenght on the low voltage side to increase your voltage drop.

Sounds like that 1200w trans they bought is way overkill for the tiny 3.9w lamps... I mean what kind of useable light would you get out of that anyways. Further something more that would concearn me is you mentioned melted sockets ??? Sounds like they are in need of a new system before it becomes a fire hazzard.

East Coast Lawn Choppers
08-21-2009, 05:45 PM
Beings it is a timer transformer I doubt I can dimmer the input. How can I put either more of a load on it or can I just put a dimmer or resitor inline on the output side ?
The 4 lights 12v on the one string are Pinnacle GL-120's w/ 12volt 35w jc pin bulbs. That is the one that melted the socket. The owner said that they get so hot you can't touch them, they will take your skin off... They look like half a ball with the bottom half having a lens, and are mounted on a wall. The way we wired it (soldered and heat shrinked the connections I really can't get my meter on the light bulb itself to get a true voltage reading at the light socket, but it can't be more than 12v because that is all I'm measuring at the transformer. Is a 35w too much for inside such a small aluminum light ? It would have to get hot wouldn't it ?

08-21-2009, 06:01 PM
I am not familiar with that fixture... is it rated for that lamp and 35w or is it rated for something else.

a 35w halogen lamp can easily burn skin. One night a couple months ago I was adjusting a system and happened to be in flip flops because we know the clients well and I happened to drop a hot mr16 35w lamp on the ball of my ankle. In all of 2 seconds it burned down 2 layers of skin and I still have a quarter sized scar from it.

Sounds to me like the system was constructed using substandard mix and match components with too many people involved.

What transformer are you using ?

East Coast Lawn Choppers
08-21-2009, 06:48 PM
The light came with that bulb. Just for the heck of it I put the one I have here onto a small 12v transformer I have here (wall transformer) it does get very very hot... no wonder it melted the rubber coating on the wire... I think it is a cheap light fixture... that is probably the biggest problem. What I think actually happened was one bulb blew out and within about a week another then once two went out she said another one went each day. So I figure the load decreasse voltaqge rose and caused the problem. What started it was the one patio paver light (hi dollar light) had the stupid crimp on connector from the factory. Well after about 11 months one of them lost connection and then a few days later another did at that pinot it lost 4 bulbs decreasing the load on the system that took out the three 194 bulbs.... I didn't think back on all that... you just reminded me of it asking the questions... I didn't measure the voltage of the system with a few bulbs out of it. Tomorrow weather permiting I'll try to remove three of the circuts and see what the voltage is with only one for a load. I'll also check here and find out what transformer it is. I think it is a good one becauseit is a stainless steel box with a nice photo cell and a timer so that you can set it to stay on all the time it is dark or have it turn off after 1-? hours after it turns on which is nice. I'll get the name and let you know...

08-21-2009, 06:53 PM
Sounds like a combination of over voltage and cheap import bulbs. Most of those bulbs are more comfortable and last longer volted in the mid to low 11s.

08-21-2009, 07:14 PM
any time you start losing lamps on a run the voltage will increase. This is why I still preffer low to mid 11's even with a quality lamp. I have a few systems out there with fixtures within spitting range of the trans. These always eat lamps fastest because I am stuck with 12v.

Another solution might be to find a trans with an 11 or 11.5 volt tap.

a note on fixtures... a quality well designed fixture is made to take the heat in which it is rated. Still really curious to know which trans your running. Sounds to me like you only have a 12v out put and not multiple taps.

East Coast Lawn Choppers
08-21-2009, 10:26 PM
It has 12v 13v 14v and 15v taps. nothing lower than 12v
It is a Best Pro Lighting Transformer... but my bad on the watts.... It says 600VA which is total I thought looking at it that it was 600 ea. 1200 total. I have the website for it but don't know if I am allowed to put that in here. I went out and looked at it and found that they are two 300W transformers and only one is being used so it is only 300W's but it is 12,13,14,15 multi tap and I looked at the wire I used and he used and it is all 10ga. not 12 as I thought previously. So it'll even be harder to get a voltage drop with AC traveling 20' or less thru 10ga. wire and only putting a total of 230W's load on it.
Can I just put a dimmer or resistor in series with it to drop voltage ?
Incandesent bulb is a pure resitive load correct ?
Kind of having a brain fart right now but.... Voltage squared divided by 60W (the 60W would take me to 290W load) would come out to a 2.4 ohm resistor with the resistor dropping 2.5V roughly or is my brain out to lunch right now... been about ten years since I did any ohm's law since I left electronics and went back to landscaping... I'm thinking the parallel load is a combined 230W load so the resistor in series if it was a pot I could adjust it to the desired voltage but the pot would have to have up to a 70W rating. Correct me if I'm wrong...

Eden Lights
08-21-2009, 10:49 PM
Hire a pro!

East Coast Lawn Choppers
08-21-2009, 11:03 PM
Hire a pro!

I thought this site was to ask questions and get help. By the way did you read the first part of the whole thing ??? I'm correcting an electricians job...
I'm trying to go back to my early courses in electronics to figure it out. Kind of forget the basics after working with plc programming and working on lasers. Don't think exciting electrons and emitting photons will help here...

East Coast Lawn Choppers
08-21-2009, 11:44 PM
Hire a pro!

It is funny... we do patios and two people asked us to do lighting. I left an electrician (isn't he the pro?) do all except I ran the conduit under the patio and ran the wires thru the walls. Now "me" the stupid person is trying to correct a "pro's" problem which he says is normal for bulbs to only last a year when they run the lights for 4 hours every single night... I think they should last longer.
P.S. I have a degree in electronics from 20 years ago, but after getting another degree in electro-mechanical (forced to by work that closed right after I finished the degree) it's hard to retain everything. So I am trying to get a little refresher and some help...

Eden Lights
08-21-2009, 11:54 PM
Sorry, Its not personal.

08-22-2009, 12:35 AM
Well Mr.East Coast Lawn Choppers,

Where do I start...I always have this rule in the back of my mind and that when it comes to safety you remove the hazard from the people or you remove the people from the hazard. Esentially where I am going with this is if you have bulbs melting thats not a good thing and you already know that. So rather than spend all your time doing OHMS law and trying to problem solve remove the hazard from the people and install a professional landscape lighting system that is going to make the customer safe and happy. Its really a no brainer.
Personally I feel the customer should be made aware of the hazard and to unplug the transformer until someone more qualified can come in and resolve the issues.
I appreciate that you are looking for advice and help with this matter but when it comes to safety I think that you will find everybody repeating what I have just written.


East Coast Lawn Choppers
08-22-2009, 10:57 AM
Ok update... I went over early to check it out before it starts to rain again... Here is what I found...
There are not 4 12V 35W quartz halogen lights on one circuit. There are actually 3 on one string and one on seperate circuit all by itself... low and behold that is the one that melted the coating on the wires.
The way I'm figuring the 35W 12V bulb should be a 4.114 ohm load so at 12V it draws 35W's so if the voltage goes up to 12.5V it would draw 38W's
I'm going to put a new fixture on and check the voltage at the fixture with a new bulb in. At that time I will check the input voltage also. When I checked it the other day it was in the heat with air conditioners running. Input voltage might have been a little low and I got 12V at the transformer, if at night time the input goes higher maybe the output voltage will be higher. ,,,, Before someone says input voltage won't change much... Our house I've seen 120V as low as in the low 100's to even high 90's on a hot day around 5:00pm air conditioners running and people using ovens etc... and we have a 200 amp service that is only 3 yrs. old. It is what we get supplied by the street...
When I find more I'll post it...
I guess I need a transformer that has a 11V tap... shame they paid a fortune for a profesional one that won't do what they want...

INTEGRA Bespoke Lighting
08-22-2009, 12:02 PM
This could simply be a matter of not enough wire between the transformer and the lamps. As a rule of thumb here, I always ensure that there is at least 15' of wire between the transformer and the first fixture (unless I have an 11V tap to work with).

'cheap' lamps and 12V lamps in general do not like to be over-volted. even slightly over 12V will drastically reduce the lamp life of the best 12v lamps. You could simply have a situation where the lamps are receiving more than 12v at during certain operating conditions.

The advice you have received here is good. Adjust the amount of wire you have between the transformer and the lamps so that they are running at consitant low 11's, use quality name brand lamps, and you should be in the clear.

East Coast Lawn Choppers
08-22-2009, 01:19 PM
Thanks Integra, I already replaced the small bulbs and I used Sylvania's in them. The one wire I have figured is only about 3' long with only one 35W bulb on it so that one needs to be lengthened. I pulled apart the other three that are identical to the one that melted the wiring and they look OK. I still think I'm going to drop the bulbs down a notch in those. They are 35W and I found 10W and 20W bulbs. I'll probably put the 20W's in to see if they run a little cooler. On Monday when I get out there and get everything back up and running I'll do voltage checks out at the bulbs and try to get it down to 11V's I'll lengthen the wire on that one to 20' or so and work from there. Beings it only has one 35W on it should I use 12 ga wire for the extra length to try to drop it more ?

Thanks again for the help.

08-22-2009, 05:40 PM
A. Loose the sig...... Way way to long
B. Do you have 35 watt lamps in this style fixture http://coppermoon.com/images/products/cm-830/cm-830_l_a.jpg

*If so there might be the problem.*

C. 10g. wire for 35 watts 15 feet away is still overkill.

to get the voltage to drop try and run 16g. All the way back to the trans. Just watch your amp load on the length of run...... I put 35watts on 50ft leads into trees all the time. Never a problem.

D. If that doesnt work Nightscaping use to sell a little box that took it down to 11.6 I think.... Im sure James could chime in on that.

INTEGRA Bespoke Lighting
08-22-2009, 05:51 PM
D. If that doesnt work Nightscaping use to sell a little box that took it down to 11.6 I think.... Im sure James could chime in on that.

Not Nightscaping.

I believe Rockscapes sells a voltage regulation device. Never tried it, just another thing to fail. Kichler also sells a 75W voltage regulator device but it is massive and is basically a big potted transformer that you (might try to)bury. Not too cheap either.

08-22-2009, 07:08 PM

I had never heard of this company (James, time to revisit your compendium?)

But at these prices...?

Well, I'll just say the fixtures look very familiar.

And maybe that you get what you pay for.

08-22-2009, 07:33 PM
here is what i would do to start with. Replace the melted fixture. Is it possible to replace that short wire run for the single fixture with 16ga wire ? This would give you around a .3 drop in that short area

RSL (rockscapes) does have a small transistor regulator you could wire inline on the voltage side of the tap. This was the idea I had that i didnt want to recomend. They are good up to 75w. They will take 12-18v and output 11.5... I have a pile here I was going to use to repair a daisy chainned job 2 yrs ago and thought better of it and ended up selling a new system.

Now... FORGET your electronics background. This is simple ohms law and voltage drop. You NEED specific readings not just "I have about 12v at the fixture" You need to know.. 12v....12.4... whatever.

Now when you replace that fixture. Even tho that may be the lamp that it came with or the same type of lamp it was probably overkill to begin with and some bogus rating and good chance is most installers using it will never have close to 12v running to it. I would get a good quality fixture and a 20w lamp or less. Still sounds like the fixture was overdriven with voltage and over lamped.

INTEGRA Bespoke Lighting
08-23-2009, 02:06 AM

I had never heard of this company (James, time to revisit your compendium?)

But at these prices...?

Well, I'll just say the fixtures look very familiar.

And maybe that you get what you pay for.

Well look at that! "pro grade" fixtures under $15 each! whowouldathunkit? :laugh:

Now we can all go out there and easily sell systems in the $50 per fixture range. This is going to revolutionize our industry!

08-23-2009, 11:10 AM
Well look at that! "pro grade" fixtures under $15 each! whowouldathunkit? :laugh:

Now we can all go out there and easily sell systems in the $50 per fixture range. This is going to revolutionize our industry!


East Coast Lawn Choppers
08-23-2009, 12:40 PM
Well look at that! "pro grade" fixtures under $15 each! whowouldathunkit? :laugh:

Now we can all go out there and easily sell systems in the $50 per fixture range. This is going to revolutionize our industry!

That was the brand of the transformer, the lights on the wall were pinnacle which probably isn't saying much. The lights I purchased were Kerr Lighting "the inventors of the original paver light" they were supposed to be good. I bought them because they matched the cobble and the others were the under the step lights. The under the step lights were around $54.00 ea. so i thought they were pretty good.
I'll definitely drop the wall lights down to a 20W max. and replace the wiring with 16ga and get the voltage down at the lights to 11-11.5. Tomorrow when I get out to that job I'll measure the voltage at the lights. My fluke meter is calibrated and is accurate so I'll let you know what I find. Thanks for all the help....