I have some 24v led strip lighting and need to know the power consumption so that i can match it to my 50w outputs from the home automation kit. On the box the tape says 12w/m and 96w/10m. I had assumed the wattage was the same per metre whether I had one meter (ie. 12w) or 10m (120w). What am I missing?

Edited October 16, 201610 yr by Trw144

I would guess that this is reflecting the voltage drop along the 10m line, So the first led sees 24V but the last sees significantly less and will be dimmer as a result. I believe some of the high power LED strips benefit from being fed from both ends for this very reason.

They also need quite beefy cable sizes too, if any significant distance away from the driver. 

Yes I can't remember what size I used but I did beef it up to cover voltage drop. Fortunately the longest runs away have shorter led strip lengths.