I'm fascinated by the fact that you are reading 12 volts with the ring attached.

Are you reading 12 volts at the other ends of the leads?

 

Can you answer the question in post #4 or at least tell us what the current rating for the ring light is. It would also help if you could measure the current to the ring light when connected to the step up converter.

Les.

 

I'm fascinated by the fact that you are reading 12 volts with the ring attached.

Are you reading 12 volts at the other ends of the leads?

If the output still reads 12V and the light is not lighting, then it is not connected.

Bob