Large Scale Central

Power supply for low voltage lights

Electronics
#1

I’ve bought a number of the Malibu light sets over the years. I would like to increase the number of lights and also to end up with a better power supply with dusk to dawn capability. Anybody come up with a better source or alternative?. Right now, I have 3 circuits with different transformers for each. Two are protected in sheds or garages. One is outside and needs to be waterproof.

To tolerate the capacity needed, I take the amps of each light, add those together for number of lights and then have a transformer that exceeds that? Isn’t that correct?

#2
Ric Golding said:
I've bought a number of the Malibu light sets over the years. I would like to increase the number of lights and also to end up with a better power supply with dusk to dawn capability. Anybody come up with a better source or alternative?. Right now, I have 3 circuits with different transformers for each. Two are protected in sheds or garages. One is outside and needs to be waterproof.

To tolerate the capacity needed, I take the amps of each light, add those together for number of lights and then have a transformer that exceeds that? Isn’t that correct?


Ric,

That’s right.

However having several separate circuits instead of just one isn’t a bad idea. That way Murphy can’t hit them all at the same time. Apart from that if I remember correctly the price of transformer goes up disproportionately as the VA increases.

#3

If you use malibu transformers, they are rated in watts. Voltage times current will give you watts, although the Malibu transformer voltage sags under load, quite a bit as it reaches full load.

Regards, Greg

#4

So is there a power source replacement available without tearing a computer apart? I don’t really plan to combine the 3 circuits, but I have a couple of places where I would like to add some more lights. I also would like to convert from being on a time to being on a dusk to dawn light sensitve swtiches. Are the big box stores, Lowes and Home depot the wrong places to look?

#5

You can get light sensitive switches at the big box stores.

Yes, go to a computer store and get a power supply that is already out, and you may have enough 12 volts.

Otherwise go mailbu on sale.

Regards, Greg

#6
Greg Elmassian said:
If you use malibu transformers, they are rated in watts. Voltage times current will give you watts, although the Malibu transformer voltage sags under load, quite a bit as it reaches full load.

Regards, Greg


“Voltage” x (times) “Current” = (equals) “Watts”

Is there another term for “Current”?

#7
Ric Golding said:
Greg Elmassian said:
If you use malibu transformers, they are rated in watts. Voltage times current will give you watts, although the Malibu transformer voltage sags under load, quite a bit as it reaches full load.

Regards, Greg


“Voltage” x (times) “Current” = (equals) “Watts”

Is there another term for “Current”?


Amps?

#8

I was hoping that was the answer. :wink:

Thanks Ken, see you next week.

#9

A few comments

  1. The transformer open circuit voltage will be higher than under load. These are not high quality regulated supplies, just a cheap transformer in most cases. So voltage droop is to be expected.

  2. The failure mode is 99% related to heat in the transformer unit. As you add lamps, the circuit draws more current and there is more power loss in the transformer, and it heats up. After the lights have been on an hour or so, go around to all 3 transformers and see how hot they are. Any one that is “exceptionally hot” - remove a bulb or 2.

  3. The plastic light housings usually take 7w or 11w bulbs. The nicer metal lights have 22w halogen bulbs. Add up the number of watts on each circuit and see if that value is consistent with the transformer rating.

Buy lights and transformers in fall when they are cleaning the shelves.

I’d suggest not spending a lot of money on garden lights as in another couple of years, they will all be LED. Its more complicated to drive an LED, and I’m not sure there will be any backward compatibility.

Feel free to email me with questions as I’ve not been a regular here since Tiny passed.

Good luck!

Barry

#10

Barry,

Good to see you posting. Thank you for the advice. I’ll try your test. I’ve got it balanced fairly well, right now. It has been working well for about 4 to 6 years. I would like to add some more lights and the problem is the length and access to the power supply from where I want to put the lights. I’ve got a couple of the solar 3 and 4 light units, but I don’t really care for the whiter light and the lower brightness they provide.

It is time to upgrade the system to dusk to dawn and l need to get a least one new transformer, so trying to figure all my options.

#11

I use the 4 watt bulbs with my malibu light system. My power pack is rated for 88 watts. 22 bulbs will be full load.

When running wire, it is just like your trains, the more bulbs the dimmer the light at the end of the wire run, so I looped the wire back to the power pack from the end of the run and my lights are much brighter. 14 guage wire with a 8 amp load will see a good voltage drop.

#12

Ric,

Some of the more pricie Malibu transformers have dusk to dawn switches & also timers so you can turn the lights on @ dusk & off @ Mid-Nite or what ever time… These can be set to turn on @ Noon so you can check the lights every day, do not have to wait till dark…