landscape lighting and transformer

[vavet]

In the ongoing rental house saga - I realized the deck post cap lights were not working. These are low voltage fixtures I installed about 12 years ago when we still lived there. They are run in parallel from a transformer with an integrated timer - an Intermatic ML44T. I'm saying parallel because I remember they would burn out one at a time and the rest of them continued to work even with one burned out. I must've wired them in parallel, right?

https://a89b8e4143ca50438f09-7c1706ba3fabeeda794725d88e4f5e57.ssl.cf2.rackcdn.com/spec_sheets/files/000/006/801/original/intermatic-ml200rt-specs.pdf?1440188663

The nice thing about the fixtures was that they required a standard automotive bulb with BA15 base - usually an 1141 or 1156 trade number. Readily available at walmart or any auto parts store.
I remember replacing a few bulbs in the time we still lived there.
I had a recent thread about changing them to LEDs. I ordered some cheap LED bulbs from amazon and set about replacing them last night...but they still didn't work. I worked back to the transformer. It's not putting anything out. Sounds like a need a new transformer. I confirmed there was 120V at the receptacle where the transformer plugged in.

It looks like that same transformer is no longer available. Ok, no biggie. There are probably better options out there anyway. Then I came across that spec sheet I linked above. This is a 120V AC input and 12V AC output. I had assumed this was a 12v DC output since it used an automotive bulb. This could explain why the LED bulbs were not working. I plugged in the transformer and rechecked the outputs with my meter on AC - still nothing. OK. It looks like the transformer is still dead.

LEDs, by their nature, are going to require a DC power supply, right? I know some have integrated electronics to rectify, but if these are intended to be automotive bulbs, I doubt they have such circuitry. Right?

Would a standard incandescent automotive bulb work with 12v AC?

I've seen other threads about low dollar transformers/timers not lasting. I see Hadco and Kichler are the respected brands. I have 5 of these little 1W LED bulbs. I need a transformer/timer to drive those. I don't want to replace the transformer again next year, but I don't want to spend $500 on a over-capacity transformer for these 5 little bulbs.
Any recommendations?

 

[kaymccampbell]

After you sure they won't work with AC? Many LED bulbs have full or half wave rectifiers built in to resolve polarity issues.

 

[justsam]

Incandescent bulbs don't care if it is AC or DC, they will work fine. Sounds like the transformer has failed. I would buy the lowest capacity available as the LEDS need very little.

 

[FredWanaker]

What is the goal here, saving the wiring? Would solar lights work just as well? I bought some cheap ones from Wallys World 15 years ago and they are still going. I think maybe I replaced the batteries with some cheap ones a couple years ago. The stands have broken on some when kicked etc., but those are available too. There are also complete kits available. With the cost of electricity so high here in CA since they went to renewables, I tossed out the old system that had a transformer and small bulbs. Lots of those small transformers were AC and they have a small replaceable fuse in them too. If it is burned up you may have a short and if so the same will happen with a new transformer.

 

[Jeff Ivers]

I use the same transformer you refer to on my exterior lighting and I have converted most of the fixtures to LED replacement bulbs.

 

[vavet]

After you sure they won't work with AC? Many LED bulbs have full or half wave rectifiers built in to resolve polarity issues.

I found a question on the amazon page for the bulbs about this. The seller replied that they would work with AC. I have an extra bulb in the truck and I think I have a 12V AC transformer here at work, so I can try this at lunch.

What is the goal here, saving the wiring? Would solar lights work just as well? I bought some cheap ones from Wallys World 15 years ago and they are still going. I think maybe I replaced the batteries with some cheap ones a couple years ago. The stands have broken on some when kicked etc., but those are available too. There are also complete kits available. With the cost of electricity so high here in CA since they went to renewables, I tossed out the old system that had a transformer and small bulbs. Lots of those small transformers were AC and they have a small replaceable fuse in them too. If it is burned up you may have a short and if so the same will happen with a new transformer.

We tried solar before I installed these. The backyard is just too shady to recharge the batteries during the day.
I took the cover off the transformer. You can see the incoming wiring where it gets wire-nutted to the wires going to the timer, but then the wires disappear in the potting material at the bottom of the container. Unless I want to spend hours chipping away the potting material, I can't see the PCB down below. If there is a fuse, it's not accessible.

 

[shade]

I just went through this and chose to use a smart transformer so the landscape lights can turn on and off with Alexa. We used a Suraielec 300w transformer, SKU ULTW30D. Works awesome if you go the new route

 

[dave*99]

I just went through this and chose to use a smart transformer so the landscape lights can turn on and off with Alexa. We used a Suraielec 300w transformer, SKU ULTW30D. Works awesome if you go the new route

The OP can use a smaller unit. 300W is a lot for for 5 lights @1W each.

 

[FredWanaker]

I found a question on the amazon page for the bulbs about this. The seller replied that they would work with AC. I have an extra bulb in the truck and I think I have a 12V AC transformer here at work, so I can try this at lunch.



We tried solar before I installed these. The backyard is just too shady to recharge the batteries during the day.
I took the cover off the transformer. You can see the incoming wiring where it gets wire-nutted to the wires going to the timer, but then the wires disappear in the potting material at the bottom of the container. Unless I want to spend hours chipping away the potting material, I can't see the PCB down below. If there is a fuse, it's not accessible.

Kudos for trying.

 

[nadogail]

I have been repurposing the "wall wart" transformers from sprinkler timers. I use them to power the relay to switch the 30 amp supply to my garage heater.

For DC loads I can add a bridge rectifier and dropping resistors.

 

[Rubberdown]

Landscape lighting is all low voltage dc in my experience. Never heard of 12v AC in landscape lighting. But I don’t know everything. If your transformer is bad, go check out volt lighting and buy a new transformer. It’ll work with your led bulbs you put in and you’ll be good to go. Remember that LED have a + and - and must be oriented correctly.

 

[dave*99]

Landscape lighting is all low voltage dc in my experience. Never heard of 12v AC in landscape lighting. But I don’t know everything. If your transformer is bad, go check out volt lighting and buy a new transformer. It’ll work with your led bulbs you put in and you’ll be good to go. Remember that LED have a + and - and must be oriented correctly.

Most landscape lighting is AC.

12v Ac or Dc Landscape Lighting: Which Is Right for You? - OcLights

12v Ac or Dc Landscape Lighting: Which Is Right for […]

oclights.com

AC (alternating current)​

AC (alternating current) is the more common type of 12v landscape lighting. AC is a type of electrical current that alternates regularly between positive and negative voltages. This means that it can be used to power a wide range of appliances, including lights and appliances.

DC (direct current)​

DC (direct current) is a type of electrical current that flows in a single direction. It’s often used for special effects or accent lighting, as it can create brighter, more focused light beams. DC is also used in batteries and solar panels, as it can store more energy than AC.

Here are some things to consider when choosing 12v AC or DC landscape lighting:

• AC is more common and typically less expensive than DC.
• AC is better suited for general-purpose lighting, while DC is better for accent or security lighting.
• DC can be more energy efficient than AC, but only if you use LED bulbs.AC is easier to install than DC.

 

[mrVanagon]

I agree that you probably have a dead transformer. For a system this small, I would probably go with something inexpensive that also has an integrated timer. I often keep one of these on my service truck for this sort of application:

Hampton Bay Low-Voltage 30-Watt Landscape Lighting Transformer with Dusk to Dawn Sensor SL-30-12-SV - The Home Depot

Improve efficiency, reduce hum and consume less load power by selecting this extra ordinary Hampton Bay Low-Voltage Landscape Transformer. Fits in budget.

www.homedepot.com

For LED bulbs, I would suggest going with a more expensive option that comes with a warranty. I use a bulb from Volt Lighting all the time. They have a low failure rate and the company is easy to deal with when I have had one fail. Note that VOLT sells bulbs in various brightness and color temperature. I almost always use 20W equivalent and 2700K.

LED SCB Bulb (Halogen Replacement)

LED SCB (single contact bayonet) bulbs designed specifically for low-voltage landscape lighting. Customizable wattage and color temperature. Encapsulated to help keep moisture away from the LED diodes. Made for use in damp locations. UL & cUL® Listed. Lifetime Warranty.

www.voltlighting.com

All of the bulbs and integrated LED fixtures I have used have been 12v-15v AC. Also all of the transformers I have ever worked with have been AC.

 

[Rubberdown]

Holy smokes it is AC. I just looked at my stinking transformer and it says AC on it. You know how much of this I have done at my house? I just always assumed it was DC 12v. I really ought to know better.


Well…. What I say stands. Get a new transformer from volt! I used their stuff at my ranch and the old house and it works great!

 

[FredWanaker]

low voltage AC is cheaper to make than low voltage DC. There is no need for a rectifier circuit and the electronic parts that stabilize the DC.

 

[nadogail]

Typically Landscape transformers work fine and last a long time. They are fairly simple to select and install.

Select a primary voltage that matches your supply and an output that matches your load. I have been lucky in finding industrial control voltage transformers that had primary windings that could be connected in series or parallel and secondary windings that can be connected as desired for the voltage I wanted.

Access to a good “Bone Yard” can be very valuable.

 

[AgingTim]

Holy smokes it is AC. I just looked at my stinking transformer and it says AC on it. You know how much of this I have done at my house? I just always assumed it was DC 12v. I really ought to know better.


Well…. What I say stands. Get a new transformer from volt! I used their stuff at my ranch and the old house and it works great!

Holy smokes it is AC. I just looked at my stinking transformer and it says AC on it. You know how much of this I have done at my house? I just always assumed it was DC 12v. I really ought to know better.


Well…. What I say stands. Get a new transformer from volt! I used their stuff at my ranch and the old house and it works great!

Like you, I just discovered that my old Malibu transformer puts out 12v AC rather than DC as I had assumed for years. But that prompts a question. Early on I wired up a string of individual LEDs in parallel, each with its own calculated resistor (assuming DC), and placed them under glass phone-line insulators mounted on short 6"x 6" posts. It looks great and it has always worked! Why, and are they just blinking so fast that I can't detect it?