Best 12 volt heater.

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Best 12 volt heater.

Postby scollard » Wed Dec 07, 2016 10:06 pm

I would like to purchase a 12 volt heater for my teardrop. Any suggestions for a good one ??? Thanks in advance. :worship:
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Re: Best 12 volt heater.

Postby tony.latham » Wed Dec 07, 2016 10:12 pm

I've found the 12V electric blankets work well for preheating the bed. Other than that... 12 volt DC doesn't work well for producing heat.

:thumbdown: :frightened: :NC

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Re: Best 12 volt heater.

Postby MtnDon » Wed Dec 07, 2016 11:38 pm

Depending on the size of your battery it is either a bad idea or a really bad idea.

A typical TD or small TT battery has about 100 amp hours capacity. That is equivalent to (100 amps x 12 volts = ) 1200 watt hours of energy). The typical battery should not de discharged more than 50% half hour would use about 750 watt hours of energy. So, 600 watt hours would last less than a half hour. Not very long.

So even with five hundred pounds of batteries you may not make it through a single night.

A cold(er) weather sleeping bag is more effective.
Our 6x12 deep vee nose cargo trailer camper conversion... viewtopic.php?f=42&t=58336

We have a small off grid cabin we built ourselves in the NM mountains; small PV solar system; 624 watts PV, Outback CC & inverter/charger ... http://countryplans.com/smf/index.php?topic=2335.0
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Re: Best 12 volt heater.

Postby Bogo » Thu Jan 12, 2017 2:24 am

Electrowarmth makes 12VDC mattress pads. They heat from below so they heat a bed nicely.
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Re: Best 12 volt heater.

Postby OverTheTopCargoTrailer » Fri Jan 13, 2017 12:42 pm

Slowcowboy

Have you ever tried heating your teardrop with hot water inside a 5 gallon bucket or small 5 gallon water cooler ? Maybe even a 2.5 gallon bucket might work.

Cheers ottct
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Re: Best 12 volt heater.

Postby ibbuckshot » Tue Feb 28, 2017 1:23 am

Greeting folks,
10/4 on the Electrowarmth 12 volt mattress pad :thumbsup: . Mine works great even on the lowest settings. If you make a mistake and leave it on high or even medium you may wake up in the middle of the night sweating your butt off. It will take a few uses to make a believer out of you and from then on you will be sold. I use to drive tractor trailer coast to coast. I would reach back to the bunk and turn it on 15 or so minutes before sliding into the bunk and it was soooooo nice to have a warm bunk. I bought it at the Calumet 76 truck stop in Chicago, Ill. about 1974. I still have it and it works great. Will be buying another one for the second bunk I am building into an ultra lite aluminum cargo conversion.
Have fun,
buckshot
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Re: Best 12 volt heater.

Postby Aguyfromohio » Tue Feb 28, 2017 9:34 am

OverTheTopCargoTrailer wrote:Slowcowboy

Have you ever tried heating your teardrop with hot water inside a 5 gallon bucket or small 5 gallon water cooler ? Maybe even a 2.5 gallon bucket might work.

Cheers ottct


If you are willing to do that it will work pretty well.
Here's the heat capacity / specific heat calculation

Specific heat of water = 4.18 Joule/ (gram deg C)
Mass of one gallon water = 3785 grams
Mass of five gallon water = 18,925 grams

Assume you bring the water to a boil before you go to bed, and overnight it cools down to 65 deg F ( 18 C)
That's a temperature change of 82 C.
Now we can march through the arithmetic of the formula for energy equals mass times specific heat times temperature change
Q = m x Cp x delta T
= (18,925) grams x (4.18) Joule/ (gram deg C) x (82) C
= 6,486,733 Joules

For our batteries we prefer to think of energy in watt* hours rather than joules, so lets convert the answer into those units:

(6,486,733) J x (1) watt hour/3,600 Joule = 1,802 watt hours.
The cooling bucket of water releases 1,802 watt hours of energy into the cabin

So a five gallon bucket of boiled water will release as much energy into the cabin as MntnDon says we ought to get from three typical batteries.
It's just another example of how small the energy capacity is for batteries compared with hydrocarbon fuels.
Two hundred years ago people used your approach with hot water bottles and bed warming pans holding hot rocks or bricks.
It will still work.
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Re: Best 12 volt heater.

Postby featherliteCT1 » Tue Feb 28, 2017 8:47 pm

Amazing! Thank you for this valuable information
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