One of my best clients, a personal training couple - trainers to the rich and famous in Silicon Valley - regularly entertain clients at their Woodside estate. I recently installed 4 outdoor type globe light thingies with an exposed copper wire with small LEDs every couple of inches wrapped around it. Each unit came with a 3.5 volt transformer, two of which have gone bad in the 6 months since purchase, one of these:



3.5 volts, .45A

You would think something like this, higher quality than the Ting Shen unit that came with it, could be purchased. I can't even find the identical unit. Most everything I find is 12v.

I did today find this item:

http://tinyurl.com/ycdd67cx

It's a 5v, 3.5A. My understanding is that the larger amp figure is not a problem, it's the voltage that will determine proper drive of the LEDs. The greater amps should allow me to power two, or even all 4 with no problem. I think.

The unit in the photo is different, stock company photo probably. The one advertised is APV-25-5. 25 watts, 5v. Electronics are hard to figure. They say 3.5A; 5 x 3.5 = 17.5, not 25.

I cut the lines between the lights and the jack to the dead transformer and wired the two together in parallel and hooked a 12v transformer to them, got real bright, unhooked quickly. I just wanted to see if there was any point in hunting for the right setup, if the LEDs were still good.

I've tried to learn about voltage reduction, 'buck converter' I gather they are called.

I found this one today, looks promising:

DC-DC Adjustable Buck Voltage Converter Stabilizer Step Down Voltage Reducer | eBay

I had earlier tried this item:

https://www.amazon.com/gp/product/B00C0KL1OM/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

with a 12v transformer, the same unit I had used to rewire some can lights to deal with dimmable LEDs for the same client. Absolutely no luck.

I don't quite get it, that transformer requires a resistor before it generates current. Perhaps that's why it didn't work.

I get that no one is going to be able to impart a degree in elec. engineering in this forum.

OTOH, I would sure like to figure how to make this work. These people pay me well because I make everything work. I really want to make this work. The lights do give a cool effect to a gazebo in their back yard, sort of the semi-formal back yard dining spot.

__________________
Te futueo et caballum tuum

1986 300SDL, 362K
1984 300D, 138K