I have just wired my wife's kitchen with 12V ribbon LED lights.
You have to use a 12v transformer to hook up to house wiring.
So I get the great idea to try this on the RV I am building
So I take a left over 12 inch section hook up a connector and pop the hood and touch to the battery terminals and.......nothin

So what am I missing? I'd love to order these 16 foot rolls cheap from Amazon rather than pay some automotive site $60 for something already wired. I'm sure it's something easy and inexpensive. I just don't know what it is

 

What do you get from that transformer ... AC or DC?

 

120V AC house current in 12V DC out
That's why I'm thinking 12v automotive voltage ought to work.
I don't know squat about electricity
just enough to be dangerious but dumb enough to try to do it myself
I'm not sure if I need some sort of 12v from van into some sort of whatever to give me some sort of constant for the LED ribbon

 

Assuming that you've got the polarity the right way around, they should work (they usually don't need any resistors or such) ... unless you've accidentally cut through a wire?

Many have a gold and a silver wire. Silver is usually looking for +12 VDC, and gold goes to ground (negative). But you should be OK swapping over (if need be) just for testing.

 

I have just wired my wife's kitchen with 12V ribbon LED lights.
You have to use a 12v transformer to hook up to house wiring.
So I get the great idea to try this on the RV I am building
So I take a left over 12 inch section hook up a connector and pop the hood and touch to the battery terminals and.......nothin

So what am I missing? I'd love to order these 16 foot rolls cheap from Amazon rather than pay some automotive site $60 for something already wired. I'm sure it's something easy and inexpensive. I just don't know what it is

Did you buy the 3528s or the 5050s?

 

3528 cool white for under the cabinets as work lights and spots from the ceiling also shining onto the workspace, warm white for above cabinet lighting, more a night light or mood lighting. Everything worked great in the kitchen. Running 3 separately powered circuits with 3 different 120 to 12v transformers.

I figure I probably need something from the 12v auto wiring to ensure I am getting proper voltage or current or whatever to the LED ribbon