What size halides?

[Staffie]

I'm doing a freebie for a dog rescue centre, I'm going to replace 5x300w tungstens with some halides.

They need good quality light to work in the evening, which is why I chose halides. What size would you go for, 70's or 150's? It's pretty damn dark up there!

Area to light measures around 20m x 15m. I can't just stick a 400w to cover the whole area as the roof over the outer part of the kennels is under cover. At present, the lights are positioned like so; one at the front, one on each side, one at the rear for a small play area and one covering another area about 5m x 10m on the side of the main kennel block.

Best price I've seen so far is £34.90 for the 70's and £36.43 for the 150's, these prices seem pretty good to me, found them on-line as none of my local wholesalers have managed to get below £43.00 (70w)?!

Cheers...

 

[bugsy]

Get the photmetric data and you will be able to work out for yourself

 

[MarcT]

The lumen output of a 300w halogen is round about 5400
The initial lumen output of a 70w double ended halide is around 5500 depending on the lamp
however the lumen maintenance isn't so good and the mean lumen output drops to around 3600 over the life of the lamp

So if you don't might the light output slowly dropping go with the 70w
If you need at least the same level of maintained light then go with 100w or 150w

R7's (double ended) are also a pain the ar*e as far as reliability goes, i would recommend the single ended lamps if possible.