I have a 12v SLA battery from an old UPS and two 10w led. I'm new to these stuff.
I connected one LED directly to the battery and in about 15mins it go hot and now one row doesn't work. I didn't know that we had to limit current to leds. So my question is, What is the most efficient way to drive this 10w led using a 12v SLA ? Adding just a resistor will waste about 2watts right ?
As I'm new to electronics, please draw me a circuit schematic :)