Convert 110v or 240v strings to 12v DC

[Ozemate]

Has any body tried to convert the standard mains powered strings with the multi function box to standard 12v strings . is it possible and if so I would love to know how

[Max-Paul]

Just for the sake of discussion, let me hit on a few points. First what is this "multi-function box" you speak of?

Icans, as far as I know, 2 volt lamps are the lowest votage lamps out there. So, you could only use 6 in series. And for LED lamps. Red, Orange, and Yellow are about 2.1 - 2.2 volts each so 5 or 6 in series. And it is worse for Blue, Green, and the varies Whites are about 3.5 volts for only 3 or 4 in series. Sure you can get more in a string, but you would have to put the above mentioned series circuits in parallel. But each series circuit put in parallel would multiply the total current by 20mA. An example, a 50 ct string of Red LEDs would be 50 / 5 = 10. So we have 10 parallel circuits times 20mA = 200mA. Taking that one step further, lets say you have 5 strings of 50 ct Red. You now need a power source that can sink at least 1A @ 12VDC.

Sorry going to get a bit winded here to demonstrate something along these lines. I converted some of these spiral 18", 3', 4' & 6' trees. The 18" trees used 35 lamps. I pulled the old ican lamps and installed LEDs from both the R.O.Y. group and from the G.B.W. group. Doing the math you can see that the one groups will drop 73.5 volts and the other group will drop 122.5 volts. Using both full wave rectifier and a resistor makes it work. The 3', 4' & 6' trees used either 35 or 50 count sections. I only used white LEDs. And found that I can only use up to 46 LEDs (161 volt dropped on LEDs) cause any more the string dims.

Sorry so long, but you really should think about a higher voltage. I am currently converting some lit candy canes. Going to put them on a D.C. controller and a 51 volt power supply (yes Paul R. I am pushing the voltage up a bit from 48V). Will be 20 reds and a 500 ohm resistor. Or 17 Green LEDs with no resistor.

Hope this helps some

[Ozemate]

The multi-function box i refer to is the little box which allows you to select slow fade twinkle etc

The reason I ask is that a lot of these strings are multi coloured lights and was thinking of using them to be controlled by the LOR DC unit

- Example of lights http://tinyurl.com/73u4cvt

[Andrew Bev]

Hi Ozemate,

You can check out this link http://auschristmaslighting.com/wiki/index.php/Bypassing_Multi_Function_Controllers

and I think you might find what you are looking for.

If you are trying to change the 240V only lights to DC this can be a lot of work. But if they already have a 24VAC transformer then it is an easy process.

[Steven]

This is a bit off-topic, but I cut a 6-bulb section from a failed 50-bulb 110v LED string, added a 100Ω resistor in series, and connected to my 12v landscape lighting. It has been working with no problems for a couple of years.

The 6 bulbs are wired in series-parallel, so that 12-volts works properly (half-wave).

[Ozemate]

Thanks Andrew that is about as close as I am going to get at the moment but trying to remove the controller and the transformer all together and supply 12 or 24 volts direct to the strings

[Robbo]

Ozemate it can be done and is as easily as working out what voltage they require in DC, when plugged into AC it drops the voltage and then from the MFC it is fed DC voltage, for example Big W strings will run on around 32VDC some tests have been done over at Auschristmas lighting