in the spec it tells: Each node produces full-color, daylight-visible light output of up to 11 candela. -
1 candela = 12.57 lumen
http://en.wikipedia.org/wiki/Lumen_%28unit%29
A full sphere has a solid angle of 4·π steradians,[1] so a light source that uniformly radiates one candela in all directions has a total luminous flux of 1 cd·4π sr = 4π cd·sr ≈ 12.57 lumens.[2]
so if you have 50 nodes, you have 628 lumen,
I might be missing something, but this is not much
again, unless I miss something