Large Scale Central

12 V Transformers

Electronics
#1

My supplier of LEDs to light my little town buildings suggested I get other opinions for landscape lighting transformers other than Malibu. They said they can surge and are basically not a first choice. However, they did not volunteer a secondary choice. I only mention Malibu because I have a few lying around and thought it good to put them to use. But if it means the possibility of blowing my whole lighting system I’m more than happy to consider a tried and true.

So I appreciate any suggestions.

Richard

#2

Well, since you need to limit the current to LEDs anyway, and the CL2 chip is an easy way to control the current, I would use them. I would think the CL2 would handle any possible surges.

#3

use the malibu if you want to save a few bucks.

But you need a full wave bridge to change to DC, and you need to filter it somewhat.

Then you can use several LEDs in series controlled by one CL2.

As David stated, you need to limit the current to LEDs, you cannot run them from a regulated voltage alone, much less an unregulated malibu transformer

Greg

#4

The LEDs I’m planning to purchase come with the resistors already installed for 9 - 18 volt use. So I believe I only need to plug them in to the system. The company sells 28 gauge Kynar wire so am thinking of putting that in conduit buried as it travels from the electrical box to the building site. Does this sound like the correct direction to go? The LEDs will be from ModelTrainSoftware or Evan’s Designs.

Richard

#5

From your other post: Under $20 on Amazon will drive a lot of 12V LEDs and has short circuit protection. One of many available: Link: http://a.co/d/cCfYUdw

#6

I have never in my 60 years seen a 12 volt AC transformer. These are usually 12.6 volts under a load but higher with a light or no load and when rectified would go to over 18 volts DC with no load.

Why 12.6 volts, that is the lead acid battery voltage when charged. Also the tube filament ratings of electronics of old.

Good news is that when rectified and filtered with a large capacitor you can get a good string of leds in series and control the current with the cl2-n2 when using 20ma leds.

#7

tube heater filament voltage was/is 6.3 volts, 12.6 voltage only applies to heater filaments in series.

Mick

#8

28 gauge wire? run in conduit?

pretty high voltage drop on that wire… are you going to run one pair of wires per LED? You certainly cannotuse 28 gauge wire for any reasonable current or any length.

Without converting to DC, you run some risk of killing the LEDs with AC, plus they will be pulsing at 60 cycles per second if you feed them AC… you can rectify your AC and filter it as I said and then see what the unloaded voltage is and see if it is safe…

But you are wasting a lot of the power in the system running a single LED from that system. If you have lots of these transformers maybe it is cost effective, or if not so many LEDs… it can be done, but please rectify and filter your AC first. (my guess is your transformer voltage is still too high, but perhaps the 60 Hz flickering is ok to your eyes)

Greg

#9

Mick, all the tubes in the 12 xxx series had 12.6 volt filaments, some were center tapped in order to use them in old cars that had 6.3 volt batteries. There were many 12.6 volt only tubes. And when engines were running the voltage was over 13 volts!!! Same for today’s cars!!