View Full Version : low voltage lighting
sunfish
08-10-2009, 03:03 PM
Would low voltage lighting do anything to help raise the temp. in a greenhouse.
Too many things to consider. Better off with a grow lamp or heater. What are you growing in San Diego? How large is your greenhouse? Location? Hydroponic? Low voltage=low current=low heat refracting from bulb and can = higher costs.
sunfish
08-10-2009, 04:17 PM
The greenhouse is 10x12x12 high. I am growing passiflora and bananas. Very seldom does it get below 40 . I already have the lighting and timer . If I can keep it above forty degrees I am fine. I was just wondering if I will get any heat out of the low voltage. Thanks
ewitte
08-10-2009, 04:17 PM
Sure about that amps usually = heat and lower voltage usually means more amps.
momoese
08-10-2009, 04:42 PM
I have a Malibu low voltage system in the backyard and they do put off some heat. The timer unit creates some heat as well.
hammer
08-10-2009, 04:43 PM
lasr winter i used a 125 watt grow lamp it put off alot of heat.
sunfish
08-10-2009, 05:02 PM
Well if they put off any heat , that is probably all I need. I am just trying to raise the temp. enough to keep them alive. I don't need a grow light , although that would be nice , it gets plenty warm here even in the winter for the plants to grow. Thanks for the help.
chong
08-10-2009, 05:16 PM
Sure about that amps usually = heat and lower voltage usually means more amps.
Yes. For the same wattage, lower voltage means higher amps. Power = Voltage X Amperes.
Any electrical device will put out heat. A 60 Watt light bulb will give off ~205 BTUs of heat (60W X 3.413BTU/W). So, any supplemental lighting you operate will give off heat inside the "chamber". However, depending on the volume, and tightness of the structure and the insulation, that heat may be localized, unless you have a hood over the device and a fan to distribute the warm air throughout the "chamber".
Richard
08-10-2009, 05:23 PM
Heat rises.
Tony, two winters ago when my dragon fruit were tiny I strung up some blue-colored "C" type holiday lights about 18 inches from the plants. (Initially closer - but noticed some heat scars.) These were connected to a thermostat for a household forced air heater: these are designed to come on below a user-selected temperature. I set mine for 40 F. Worked great -- of course here in San Diego the temperatures in that area would not have dropped below 33 F. I calculated that they cost less than a penny an hour to operate.
sunfish
08-10-2009, 05:51 PM
I was thinking of the safety factor using the low volt. versis 110 volts.
Richard
08-10-2009, 05:59 PM
True, its a good idea for your lighting -- which will not be located in a good place for the small amount of heat you desire. I thought a string of holiday lights about a foot above the ground with a simple fuse was fairly safe for keeping the temperatures above freezing (again, in USDA zone 10).
chong
08-10-2009, 06:57 PM
Heat rises.
That is a misconception. Heat flows naturally in any direction from warm to cold media. It is warm air rises above the cold air, as in Hot Air Balloons. The density of warm air is lighter than cold air, that is why it floats over the cold air. In a small enclosure with adequate insulation, the interior of the enclosure will get hot/warm regardless where the heat source is placed. In larger enclosures, with adequate insulation, sufficient to prevent the transmission of heat output of the source to the outside, the chamber will get hot/warm, regardless of the heat source placement.
bencelest
08-10-2009, 07:18 PM
Why not put a string of Christmas lights around your bananas or plants that you want to protect? It's cheap and easy to take off. And that's what I do year after year to my delicate plants meaning plants that are still small. Once the plants are established or growned for 3 years or above, they are on their own.
I use 100 strings of clear Christmas lights the small kind not the medium base and I can protect about 3 3 gallon pots. I don't worry too much about safety because I believe that they are approved for outside use. I don't even use fuse or protective device because I believe they are safe to use. I just plugged them in to a timer and to an extension chord depending what time I want them on and off.
Low voltage won't give you the heat that you want because like Chong said Watts or power = current x voltage and in an alternating current such as we are using times the power factor. PW of incandescent lamps are 1. And watts is heat. So the more watts the more heat it will give off. At low voltage you need to increase the amperes to give off more heat and that's bad. You need much bigger wire to carry the current you need for warmth. That will shoot your expenses high. And 1/10th of an ampere can kill a person depending the right circumstance.
sunfish
08-10-2009, 07:19 PM
I am sure the best thing I could do is make sure the greenhouse is sealed. That is alot of calking to do, maybe someday I will do that. For now I am hoping all the jugs of water I have inside and a little help from the lighting will do the trick. Thanks
sunfish
08-10-2009, 07:22 PM
Ok Christmas lights it is.
And the answere is.....YES. There are some great ideas in this thread. Keep us posted on your progress.
bencelest
08-10-2009, 07:31 PM
Tony:
I might add that don't buy the LED kinds. They don't give any heat at all.
I bought mine at Sears right after Christmas. For a 100 strings for 75 cents. They were 75% off so I bought a bunch so that if a string don't light I just throw them away.
And you are in San Diego. If you have a nice sealed area and water jugs are all you need. Try a trial run. Buy 1 string. Plug it in and put your hand close to the light. If you can feel the heat generated then that's the one you want. If you buy the medium base lights they will cook your plants. And you won't be able to put your hand close to the light because it is so hot.
r3tic
08-11-2009, 07:09 AM
If you have room, put a some rain barrels full of water in the green house. Water is a great heat sink, gets warmed in the day lets off heat all night.
Lighting is a very inefficient way to provide heat.
There are ceramic bulbs that fit in a standard light socket that produce infa-red heat, not those red bulbs that you see keeping meat warm at a buffet.
These are non light emitting and have been used in Europe for decades and can be found here through any place that carries reptile supplies.
They are available in several different wattage choices and you can put a rheostat inline to raise or lower the output.
They aren't cheap but they last a long time.
I've had them last as long as 5 years of almost continuous use.
bencelest
08-11-2009, 09:50 AM
Lighting is a very inefficient way to provide heat.
There are ceramic bulbs that fit in a standard light socket that produce infa-red heat, not those red bulbs that you see keeping meat warm at a buffet.
These are non light emitting and have been used in Europe for decades and can be found here through any place that carries reptile supplies.
They are available in several different wattage choices and you can put a rheostat inline to raise or lower the output.
They aren't cheap but they last a long time.
I've had them last as long as 5 years of almost continuous use.
rheostat, ceramic bulbs and availability plus your gas looking for it =$$$$ and
To me anything that exceeds my budget is a no-no.
So I go the cheapest way. And the most practical. You can spread your Christmas lights a long distance to protect more plants for your money.
"Lighting is a very inefficient way to provide heat." I question the inefficiency of lighting versus the expense by other means. How many times you use them anyways in a year? 3 or 4 times at most?
Inefficient in terms of power drawn vs. what actually gets turned into heat, in lighting most of the power is used to produce lumens and there is some heat as a byproduct.
A non light emitting unit is designed to produce heat.
A rheostat is an option but a very inexpensive method to control output.
The bulbs screw into a standard socket and can be used with a clip on light.
Personally, I wouldn't be without them because they provide deep penetrating heat for animals that may be sick or just need some heat and the lack of light offers an opportunity for uninterrupted rest.
Just another suggestion that may not have been considered.
In this day and age zero gas should be used to drive around finding anything considering where this discussion is taking place, but even before the internet a phone book did wonders for finding who carries what in your locale.
I definitely agree that at the price you can get christmas lights they are probably worth having a few sets.
bencelest
08-11-2009, 11:08 AM
Inefficient in terms of power drawn vs. what actually gets turned into heat, in lighting most of the power is used to produce lumens and there is some heat as a byproduct.
A non light emitting unit is designed to produce heat.
The bulbs screw into a standard socket and can be used with a clip on light.
Personally, I wouldn't be without them because they provide deep penetrating heat for animals that may be sick or just need some heat and the lack of light offers an opportunity for uninterrupted rest.
Just another suggestion that may not have been considered.
I definitely agree that at the price you can get christmas lights they are probably worth having a few sets.
I read here that the lumens induced by light bulbs is a means to induce photosynthesis on the plants' leaves. Depending on the lumens intensity you can have the plants grow vegetatively or to produce fruits .
I certainly agree that you can also use the ceramic bulb that you mention. In fact that is even maybe better than my suggestion.
I am just not used to it or maybe I don't know where to buy them.
Having said that, I think I still will stick to Christmas lights because those saved many of my plants from below zero weather here in Salinas.
In fact it saved my California gold fruit and leaves when I wrapped the pstem, fruit and leaves and spread to the surrounding soil first the Christmas lights then on top was clear plastic (to keep the soil warm and to keep it dry also from the rain) the Christmas lights and wrapped them with burlap and clear plastics during the extreme cold 4 or 5 years ago when the tempts dipped below zero for more than 1 week. And when I bought it that was a newly planted CG with flowers. A matured plant.
I did not know what I was doing but it worked.
I also found out that I don't need a sealed greenhouse in my area. All I need are Christmas lights spread around the bottom of my plants and a clear plastic cover overhead.
The only drawback are my neighbors wondering why I still lit my Christmas lights even after Christmas in my backyard(lol).
bencelest
08-11-2009, 11:17 AM
Now that all of my plants are grown and big, I don't use Christmas lights anymore. They are on their own to depend themselves from cold.
For testimonial, look at my plants I've grown in my backyard at my photo gallery.
You can see the California Gold that I am talking about.
bencelest
08-11-2009, 01:22 PM
<a href=http://www.bananas.org/gallery/showphoto.php?photo=21008><img src=http://www.bananas.org/gallery/watermark.php?file=21008&size=1 border=0></a>
Here's my CG that survived the freeze because of Christmas lights. Notice the CL at the bottom of the hands? This is after I removed the burlap and clear plastics that was wrapped around the fruit and P-stem.
bencelest
08-11-2009, 01:26 PM
<a href=http://www.bananas.org/gallery/showphoto.php?photo=21009><img src=http://www.bananas.org/gallery/watermark.php?file=21009&size=1 border=0></a>
The survivors of the freeze.
Look at them now! It's a jungle out there.
Notice also the Christmas lights that I used at the floor.
I think Salinas gets similar weather to Vallejo, maybe you get a tad colder but not much.
There is another product sold for greenhouse use, it is designed for starting seeds and comes in rolls, you can buy it by the foot and it is like a heavy (15-20 mil) poly and it has an element sandwiched into it.
It's draw per foot seemed very low and you connect little clips to it to add power, it can be run any length and due to its flexibility it can be wrapped fairly easily.
I got a few samples from a reptile guy but he told me it was just greenhouse seed bed warming tape that he had his name put on.
It is designed to get wet so it should be very safe.
I'll put a couple pics in my photo gallery.
Ray
r3tic
08-12-2009, 10:20 AM
rv...I have used that product for heating my snakes, and unless they have changed the power connection method, you should avoid getting them very wet. They will short out. That being said, it is a very good product. This is where I purchase it...bigappleherp (http://www.bigappleherp.com/Flex-Watt-Heat-Tape?sc=2&category=14)
bencelest
08-12-2009, 01:11 PM
I bought a product to warm up the soil in greenhouses. I bought it on EBay so I was not sure of the load (ampere drawn). When I got it and found out how much amperes it would be drawing, I did not used it one bit because they were too much for my money. Finally, I just threw it away.
You see I want to grow bananas the cheapest way possible. As far as I am concern, for free, and take advantage the environment can offer, the microclimate, the big trees, the walls of your house, the sun, etc.....
But if you have the money to spend, go for it.
bencelest
08-12-2009, 01:28 PM
Ray:
I have a sister living in Stockton. I usually go to their house. I think Salinas is less colder than Vallejo because we are closer to the ocean which serves as buffer for temperature changes and we are more South than You.
During Winter It's Cold out there in Stockton and Summer is just plain Hot.
That's why I don't need much protection during Winter here except during that Arctic blast that really affected the whole California. And it was during that arctic blast I used Christmas lights to protect my newly planted California Gold and it worked.
Benny
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