how much light to use?

[southernstoner]

i have an upright freezer i am using for a growcab...one big door...i am using cfl lights for now...can i run a 250w cmh light in there...the cmh is a ceramic metal halide for use with hps ballast...made by philips...they make it in 250w and 400w right now...hell of a spectrum...thanks...SS

 

[pilot error]

I would say you are only limited by the heat it throws off. Eliminate that and you should be good to go with either of those bulbs. Check into cool tubes or vented hoods.

 

[hubcap]

can ya fit T5s along the sides standing up?

make it like a BIG phototron, lol

 

[southernstoner]

right now i have a 200w cfl in a hood hanging at the top and small cfl in surge protectors on the sides to get started with...i have pics in the members gallery...i just want a CMH bulb in there if 250w wont cause too much heat...before i put in the fart fan on top 6 cfl bulbs had it to 110 deg...the 200w had it to 135+...since putting the fan on top with the 4 cfls running the temp has been 74/85 high/low and the humidity around 54%...i may just opt for the 400w CMH in a 4 x 4 area...leave this with cfl's...SS

 

[forman]

As much light as possible without over heating! You might just have to run a test to see.

 

[HerbalTea]

...before i put in the fart fan on top 6 cfl bulbs had it to 110 deg...the 200w had it to 135+...since putting the fan on top with the 4 cfls running the temp has been 74/85 high/low and the humidity around 54%...

Most folks seem to underestimate the amount of heat fluoros put out because they stay cool enough to touch. But a typical bathroom fan has enough ass to change the air in my own apartment in only an hour or two, if I were to leave it running all the time. That oughtta be plenty in a fridge sized cab. I've got a sneaking suspicion either your passive air intakes need to be enlarged, or maybe you're drawing in already warm air.

 

[hubcap]

Most folks seem to underestimate the amount of heat fluoros put out

?????????????

 

[southernstoner]

the intake air isnt heated...ambient air temp coming in...i have 3-2in holes under the fart fan and 3-2in holes for passive intake...when the door is shut the fan doesnt change speed so i dont think there is any negative pressure there...SS

 

[tngreen]

your intake hole area needs to be twice your exhaust hole area. for example if you exhaust is 4" (~12.5 sqin) you would need atleast 25 sqin for your intake (or about a 6" hole). id say add a hole or make your intake holes a little bigger and see if that helps. you could probably do a 250w cmh in a cooltube.

 

[zino13]

Re Heat

Greetings,

I have tried a setup close to yours.

My take was to vent on the top ie 4" opening with fan and on the very bottom 2"X4" opening.

This gave a full passive airflow via the temp hot air rising cool air in.

 

[southernstoner]

thanks for the replies...SS

 

[dirtman63]

tngreen said it best your intake(passive) should be one and a half times the size of your exhaust.My first cab i used a 4'' vortex inline fan with 3-2'' holes for passive intake.I had to pull hard to get the doors open,it had awesome neg pressure.another good trick is to use black pvc elbows to light block your intakes and I use nylons to keep dust and stuff out.Good Luck & Stay Safe!!

 

[Scuba Snacks]

back pvc elbows and nylons a good idea and doesent take much