75 watt too much for water heater

[nicolekos]

will it melt the plastic?

 

[emma p]

I would not have a light on water... It can melt it and is dangerous for the chickens if a fire was to catch. I would just bring out warm water whenever I can (if possible). I think if I was to heat my water the best way to go would be with a dog water heater that is made for that use.
Hope that helps a little...

 

[nicolekos]

I read that so many ppl do it with no problem, I'm not worried about it. Also Its not exactly walking distance for me to change water four times a day.

 

[azygous]

The principle of heating something that has water in it is that the container will get no hotter than the water that is in it. Now, that said, should the plastic container become empty, the water having spilled or been drunk, then the 75 watt bulb would likely melt the plastic water base.

I use 40 watt bulbs in my cookie tin water heaters, and have never had any problems.

Today it was seven below zero (F) in my runs, and the water was kept from freezing in the water basins, even while the top part of the reservoir was beginning to freeze. 75 watt bulbs are more than is necessary for these very efficient little water heaters to function adequately.

I used to haul hot water out three times during a day like this one to replace frozen water. I swear these cookie tin water heaters are the best invention EVAH!

 

[azygous]

You ARE talking about cookie tin water heaters, aren't you? Or just hanging a light bulb over a plastic water fount? I guess I just assumed it was a cookie tin water heater with a 75 watt bulb inside that you had a concern about.

 

[MeepBeep]

So many variables to consider and take into account... Without knowing the details of your setup there is no one answer... For example your typical 5 gallon heated water bucket is about 130W but that also has a thermostat built in and the heating element is large so that heat is spread out over a big area and thus doesn't get to the same max temp as if it was confined... Same with using other types of heaters, as long as they are submerged in water and thermostatically controlled wattage is much less important then if they are uncontrolled or not submerged...

If you are doing a cookie tin heater, since it's after Xmas go get a few strands of 100 mini Xmas lights on clearance, each 100 mini lights is about 40 watts... Try with one strand if it works stick with that, if you need a little more heat put two strands in there, and I HIGHLY recommend you get a thermo-cube so that it only runs when it's below freezing, also wire it properly and safely to a CGI socket...

The Xmas lights are nice as the heat is spread out over a larger area, not one big hot spot like a single bulb, also if one or two bulbs blow out no big deal with current strands that stay lit as the bulbs blow...

http://www.homedepot.com/p/Unbrande...rmostatically-Controlled-Outlet-TC3/100210525

 

[nicolekos]

I have a 75 watt in the cavity of a cinder block. I keep the water in the run attached to a thermocube. I hardly believe that a 40 or even 60 watt would keep the water thawed enough with the consistent cold out here. And everyone I've talked to personally aren't worried that it'll melt. I asked them after I made this thread, so I am very confident in it.

 

[MeepBeep]

I hardly believe that a 40 or even 60 watt would keep the water thawed enough with the consistent cold out here.

Some quick figures / calculations...

1 Watt is about 3.41 BTUs
1 BTU will raise the temp of 1 pound of water 1° F per hour
1 gallon of water is about 8.3 pounds

So you need about 8.3 BTUs to raise 1 gallon of water 1°F/hour or about 2.4 Watts to raise 1 gallon of water 1°F/hour and in 24 hours that will raise the temp of the water +24°F

That all assumes no loss, not real practical in the real world but it's a start, as it shows that 8.3 BTUs would theoretically provide +24° of temp gain to that gallon of water, so it could theoretically keep that gallon of water thawed until the temps dropped bellow say 8°F average for the day... But, again we have losses that are not figured in, so the number is mostly nonsense...

With a 40W heat source, you have 136.4 BTUs, lets say your water container is 1 gallon or 8.3 pounds of water, that 136.4 BTUs can theoretically raise the temp of that water 16.4°/hour or +394° a day over ambient temp... But, again that is no loss , not real world but it shows us something...

It gives a good idea to build upon because in the above you have a safety factor of 10x to cover losses for that 40W of heater, and using that 10x safety factor we can guess that it could theoretically keep that water liquid down to about -7°F even if 9x out of the 10x safety buffer was lost...

So anyway we return to the real world, and jump to practical numbers based on my experience with outdoor ponds heaters, not theoretical math...

If your water container is in the coop, with no wind blowing over it and moderately insulated by the coop wall and bucket itself, you will need about 4 watts of heat will keep 1 gallon of water about +30°F above ambient temp over the course of a day... Way too many 'insulation' and loss factors to get a solid number but it's pretty safe to say that a 40W heater should do a decent job at keeping a gallon or two of water above freezing temps inside a draft free area like inside a coup, until we get into extreme negative ranges...

If your water is outside in the run with no insulation and wind or air blowing over it that is an entirely different story, you can easily expect to to use 5 or more times the heat to accomplish the same thing, meaning that that 40 Watts of heat could very well struggle to keep even a single gallon liquid even at a moderate freezing temps...

Also consider there is going to be a world of difference in keeping a nearly completely enclosed water system like a sealed nipple water system liquid vs a watering system that has open water surface exposed to the wind, exposed water will drop in temp much faster... And also consider that if you have pump moving the water it's much easier to keep it liquid as it's much harder to freeze moving water and takes temps well below freezing to do so...