wiring lights

[Jagsy]

hi, I have led lights all around my garden, there will be about 20 altogether...... can I just run 1 cable all around my garden from a 12v power supply and join each light to the cable via its own stepdown voltage regulator located in a waterproof enclosure ( they are 3.2v leds ) or will I need to run a cable for each light to its own 12v adapter

 

[ronsimpson]

1) Don't run 40 wires. Don't use 20 adapters. Don't run 110 volts AC in you garden.
2) You can regulate each set of LEDs at at LEDs.
3) 12 volts is safe.
4) LEDs are current devices not voltage devices. I know they say 3.2V but don't put 3.2V on them. (What current are they rated for?)
example; use two LEDs (about 6 volts) and a resistor (about 6 volts) Size the resistor for the correct current. (or a little less)
6V 1k ohm 6mA
6V 100 ohm 60mA (just math)
5) The low voltage garden wiring uses "extension cord wire".

 

[MikeMl]

1) ...
5) The low voltage garden wiring uses "extension cord wire".

Use the stuff with the extra-heavy insulation intended for direct-burial sold at Home Depot to run Malibu lights.

 

[Jagsy]

hi ronsimpson and mikeml... ok..this is what I have done, I had solar lanterns and globes around my garden.... they didn't work very well from solar because in north of England the sun is not around long..especially in autumn and winter... I decided to turn them to mains powered via a resister a voltage regulator and a 12v dc adapter the current of the leds are 20ma.. I have all that sorted.... I just need to know if I can run 1 cable from a 12v dc supply around the garden and then connect each lm317 regulator to the cable at different points in the garden via a junction box for each regulator or will I need to run a cable from each regulator with each regulator having its own 12v dc power supply

 

[Nigel Goodwin]

As long as the 12V PSU can provide enough power, then one is fine.

 

[ronsimpson]

20 LEDs and 20mA = 400mA
A 12V 1A power supply will run cool.
I think you want a supply that can handle a short circuit. OR Maybe you are care full when digging.

 

[MikeMl]

**broken link removed** designed for direct burial.

 

[audioguru]

We talked about this on another thread or on another forum.
The fairy LEDs are already in strings, the LEDs are matched well and can be powered by one LM317 voltage regulator set to 7.5V and one series resistor. The LM317 was not hot.
The lanterns each have two paralleled white LEDs and each needs its own resistor from 7.5V. One LM317 can easily power the strings of fairy LEDs and some lanterns.

We know nothing about the globes. How many LEDs in each globe? Are the LEDs in each globe paralleled?