The brightness at 12V was disappointing, so have the LED - strips tested more accurate. At 12.0V -> Current consumption 0,72A -> 8,64W at 5m -> 1,73W / m At 13,0V -> Current consumption 0,93A -> 12,09W at 5m -> 2,42W / m At 14,0V -> Current consumption 1,13A -> 15,82W at 5m -> 3,16W / m At 15,0V -> current consumption 1.35A -> 20,25W at 5m -> 4,05W / m At 16.0V -> Current consumption 1,55A -> 24,80W at 5m -> 4,96W / m According to the data an output of 4.8W / m should be reached at 12.0V, from this information that I present are LED - Strip away. There are approximately 15,8V required by the specified performance goal. Due to the increased input voltage of the entire LED strip is much warmer, this is a material adverse effect in terms of life. Understanding Brightness (lumens) No information is given in the data sheet. The supplier should finally indicate the actual data, or do not sell this product further.