Led Driver/Power Supplies convert Mains AC voltage to 12VDC voltage, unlike on a boat car, mototcycle or mobile home where the source is a leisure battery, Domestic/Commercial application do not have batteries readily available. So we use mains to convert AC to DC allowering us to power these 12VDC led strip lights. The longer the strip or higher brigtness will require more power than a small strip. As a easy guide we say a 3528 led strip consumes 4 watts a meter so 5M = 20Watts, a 5050 consumes 8 watts a meter so 5M = 40Watts, whilst the 5630 is around 15Watts a meter so 3M = 45watts. Depending on the LED type and length determines the led driver suitable for your application. We always over rate our led drivers, as you would not run you car full out all day long. We have inline-led drivers, sutable to be connected to a fuse spur light switch or plug in the wall adaptors, suitable to be plugged into a 13A socket socket.