I had it on the battery out of the car on the floor.

Just buy this and deal with it:

 

http://azsurplus.com/index.php?main_page=product_info&cPath=1_9&products_id=1663

 

obviously no one else here has worked with downlights.

Sorry Jono, I just clicked on the jaycar link you put up, I didn't realise that it also did capped the amperage, I thought it was just a voltage resistor.

I just got my money back. Will look for something else to use as reverse lights.

Still got the blown one?

Still got the blown one?

Yes.

Since the board in it is most likely fubared you should try to wire direct to the light, I have some jewellery shop downlights here that I run off a 12v battery and they are bright as hell.