12 Volt Landscape light dimming

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A/A Fuel GTX

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WI & AZ
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Electrician
Haven't worked with 12 volt landscape lights in quite awhile. Installed an LED system and was wondering how to correctly dim the lights that are way too bright. I have an electronic transformer rated at 200 watts. Would I install a dimmer on the line side of the transformer ( 120 V ) or the load side of the transformer (12 V)? I'm thinking I need an ELV dimmer on the load side but need some guidance.
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
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Electrical Contractor
You need to look at the specs of the driver to see how it can be dimmed or even if it can. You generally don't dim the output of LED drivers.
 

A/A Fuel GTX

Senior Member
Location
WI & AZ
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Electrician
You need to look at the specs of the driver to see how it can be dimmed or even if it can. You generally don't dim the output of LED drivers.
I can't find any details about the transformer except that it puts out 200 watts at 12 volts. It just powers 12 volt LED landscape lights kind of like the old Malibu lights only these are higher end fixtures. The fixtures take G4 lamps.
 

Dennis Alwon

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Usually, a dimmable driver says it is dimmable on the unit itself. If it isn't dimmable then nothing will work. You can replace the driver with a dimmable one
 

winnie

Senior Member
Location
Springfield, MA, USA
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Electric motor research
Usually, a dimmable driver says it is dimmable on the unit itself. If it isn't dimmable then nothing will work. You can replace the driver with a dimmable one
This.

You need to check the specs of the 'electronic transformer' and of the LED lamps.

The 'transformer' is most likely some sort of isolated switching power supply.

The supply could be designed to very carefully regulate its output, and disregard any input changes. Such a supply could ignore an upstream dimmer.

Or the supply could be designed to detect upstream dimming and adjust its output.

A LV dimmer on the output is probably some sort of PWM device. The power supply can likely handle its output being switched, but again check.

It might be easier to replace the 'transformer' with one that dims. But you also need to check that the LEDs will respond correctly.

Jon
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
This.

You need to check the specs of the 'electronic transformer' and of the LED lamps.

The 'transformer' is most likely some sort of isolated switching power supply.

The supply could be designed to very carefully regulate its output, and disregard any input changes. Such a supply could ignore an upstream dimmer.

Or the supply could be designed to detect upstream dimming and adjust its output.

A LV dimmer on the output is probably some sort of PWM device. The power supply can likely handle its output being switched, but again check.

It might be easier to replace the 'transformer' with one that dims. But you also need to check that the LEDs will respond correctly.

Jon


Yes, the photo I posted was to get an idea of what is available. As I stated the site 1000bulbs.com has many led drivers with varying specifications. He has the old one so he should be able to get other info if necessary
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
Since you say the there is no information other than 200 watts on the power supply how do you know its electronic? Most landscape lighting uses 12 volt AC magnetic transformers. The LED fixtures and replacement (retro fit) lamps have their own LED drivers built it.

If it is a transformer and is hardwired you most likely can dim it with a standard magnetic low voltage dimmer. The individual fixtures and lamps need to be dimmable though.
 

Amps

Electrical Contractor
Location
New Jersey
Occupation
Electrical, Security, Networks and Everything Else.
Check the manufacturer specs of the light fixtures. Some manufacturers have fixtures that dim and others that do not dim.
 
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