5watt 12volt heater?

Here's the situation:
I have a small amount of pipe exposed to the outside. (no way to drain it or get power to the location)
My plan is to build an insulated box around it and use a solar panel, battery and thermostat to trigger a small heater when ever the box gets cold.
Must be a better heater/thermostat... here's what i was thinking of buying:
Panel: http://www.solarhome.org/powerupbsp-5125wattsolarpanel.aspx Battery: http://www.solarhome.org/12volt18amp-hoursealedleadacidbattery.aspx
Would a heater like this work? http://store.rvdirect.com/rvdirect/details.php?ITEMA20361
A thermostat like this? http://www.comfortgurus.com/product_info.php/products_id/1483
Thanks!
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Assuming you're thinking of one solar panel, you're proposing to use a heater drawing 16-17 amps and recharge the battery with a current source of less than half an amp. So, assuming 100% efficiency, which you won't get by a very long margin, you would need 35 minutes of sunshine to cover one minute of heat. Or six hours for ten minutes. Hmmmmm
John
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On Nov 16, 4:25 am, "John Nice" <johnDOTniceATbtinternetDOTcom> wrote:

In theroy the heater would run very rarely. Just to keep the super insulated box above 32 degrees. Are you recommending more panels? Or is there a bigger one you see that would work at the site I linked to?
Thanks very much!
Elijah

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In article

You don't say how long your pipe run is or what external temperatures fall to in your neck of the woods. If you insulate well I think rather less power will be needed than you are proposing.
You ought to look into heating tapes like these:
http://www.globaltrace.co.uk/id8.html
or consider a suitable length and gauge of resistance wire.
You wrap the stuff round the pipe and then enclose in insulation.
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It's a very short run about 12" sticking out. Brooklyn ny, maybe down to 0 once and awhile but mostly 20s
I'll look at that heat tape, thanks for you help!
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It's a very short run about 12" sticking out. Brooklyn ny, maybe down to 0 once and awhile but mostly 20s
I'll look at that heat tape, thanks for you help!
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eksaint wrote:

I've seen it done with a power resistor clamped to the pipe. A 30 Ohm resistor will dissipate about 5 Watts when powered from 12V and can be had for little or nothing. As someone else said though you can buy heat tape specifically for this purpose.
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