Advantage/Disadvantages running lights on 24hr a day for Veg.

jimmyspaz

Well-Known Member
That is the silliest thing I've ever heard.
No !! Power surges on ignition use more power than leaving the lamps on constantly, also turning lights on and off ages bulbs rapidly. I only put my veg room lighting on a timer in the spring when it's full of clones for outdoors,and I want them to see some diurnal variation.
 

metagrower

Well-Known Member
Let me make sure I understand this correctly... you are telling me that to turn the light on it consumes more power than the light would consume over a period of 6 hours? Thus making it more economical to run your lights for a full 24 hrs/day rather than turning them off for six or more hours every night?

I would need to see a credible source citation on that to believe it.
 

metagrower

Well-Known Member
Furthermore, I can understand how one might believe that your bulb only gets a limited number of starts, but don't you think that might also be proportionally relative to the number of hours the bulb is rated to burn? How would the wear caused solely by extinguishing and igniting the bulb once a day be greater than wear on the bulb caused by 6 hours of continuous burning?
 

jimmyspaz

Well-Known Member
Meta, check manufacturers specs, this is why factories that use high-bay lighting (HID lamps) will leave the lights on 24/7,It's not really for security,but for economic reasons. I don't have the figures at hand, but this is what I learned in trade school. It's the power surges on ignition that stress the bulb elements which can cause the bulb to fail. Maybe my electrical teacher didn't know what he was talking about but everything else he taught me was accurate.
 

jimmyspaz

Well-Known Member
Ok reality time. I use a magnetron 400watt MH ballast and Phillips MH bulb for veg. On 24 hours I get about12 months from a bulb,on 18/6 about 8 or 9 months. These bulbs are $40+ wholesale,I think around $70 retail (CDN).I think that any added energy costs are less than what is used in ignition surges + bulb replacement.
 

scabiesbaby

Well-Known Member
i run my clones 24/0 and my seedlings at 18/6 i have seen a dramatic increasein males at 24/0. but if your using clones. i have seen no increase in the hermie tendency at 24/0.
 

BigBudBalls

Well-Known Member
lights that stay on for 24hrs run cheaper then lights going on & off all the time

Nope. The inrush current isn't that much. Think about that. Turning on uses the equivilent of 4-6 hours of run time? The cord going to the wall would melt (well trip the breaker actually)

I had a kill-a-watt on my lamp and the wattage started low, then crept up was the bulb warmed up to running temp/light output. (HPS)

Mythbusters also did a thing on this with Floros. Turning on used about 23 seconds of 'on' time.
 

jimmyspaz

Well-Known Member
MH have high ignition surges, HPS do not , Different situations. A HPS slowly ramps up power where a MH has a surge to ignite. The cooling and heating of bulb elements is also a factor in bulb life.
 

metagrower

Well-Known Member
MH have high ignition surges, HPS do not , Different situations. A HPS slowly ramps up power where a MH has a surge to ignite. The cooling and heating of bulb elements is also a factor in bulb life.
That information is quite pertinent.

Also, could you please provide a site where one might find the specs for power consumption 'on ignition' for various wattage MH and HPS lights so that we might be able to compare for ourselves? I am not quite certain what terminology is appropriate to get good results from Google.
 

jimmyspaz

Well-Known Member
As I said before I learned this at trade school, 35 years ago, so I don't really have all the figures and references handy. I'm pretty sure my instructors knew what they were talking about though. Sorry I can't be more help. I can only share my experience and training.I remember seeing the power usage on ignition graphed out somewhere though.
 
Top