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 > 12V heater run straight from solar panel

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DarkSkySeeker

Freestone, California

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Posted: 03/26/20 02:53pm Link  |  Quote  |  Print  |  Notify Moderator

Flute Man wrote:

I have a 12 V 300 W heater in my rally compartment. It draws 25 A so figure yours accordingly.
Electric heaters have a very simple formula.
Watts Divided by volts equals amps.

Did you buy it online? If so, could you share the link?


There is something special about camping in an RV.
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Boon Docker

Mountain Foothills of Southern Alberta

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Posted: 03/26/20 02:58pm Link  |  Quote  |  Print  |  Notify Moderator

There are a lot of 12v heaters on Amazon and Ebay.
Those 12v heaters are real power hogs. You would need a minimum 400 watts of solar to run a 300 watt heater. Which would put out very little heat in a large space.

time2roll

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Posted: 03/26/20 03:00pm Link  |  Quote  |  Print  |  Notify Moderator

You will be lucky to keep the 12v battery charged and burn propane running the furnace.


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Lwiddis

Mojave, Kern County, California

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Posted: 03/26/20 03:20pm Link  |  Quote  |  Print  |  Notify Moderator

25 amps? That’ll drain a battery. Or require five 100 solar watt panels producing at almost max.


Winnebago 2101DS TT & 2020 Chevy Silverado 1500 LTZ Z71, 300 watts solar-parallel & MPPT, Trojan T-125s. TALL pole for flags. Prefer USFS, COE, BLM, NPS, TVA, USF&WS, state & county camps. Bicyclist! 14 year Army vet - 11B40 then 11A - (MOS 1542 & 1560)


DrewE

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Posted: 03/26/20 03:29pm Link  |  Quote  |  Print  |  Notify Moderator

DarkSkySeeker wrote:

What if I bought 5 of these, wired them in parallel, and mounted them on a board?

PRODUCT LINK


At 12V, Ohm's law says that 1.2A would flow through each one, which means a dissipation of a bit under 15W each. Total wattage would be around 150W. To get 50W power dissipation, the applied voltage would have to be a bit over 22V.

According to the resistor data sheet, with no heat sink (i.e. mounted on a board), rated dissipation is 14W. To dissipate 50W each you must have a heat sink to keep their temperature reasonable. In either case they ought to be mounted on something that can take the heat; a wooden board would not be the wisest choice in my estimation.

$35 seems like a lot of money to spend for the anemic results you'd tend to get.





2oldman

New Mexico

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Posted: 03/26/20 03:38pm Link  |  Quote  |  Print  |  Notify Moderator

DarkSkySeeker wrote:

Is there a heater product that can run off the 12V that comes directly off my portable solar panel? .
One panel? You'd be lucky to heat an ant farm.

wopachop

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Posted: 03/26/20 03:39pm Link  |  Quote  |  Print  |  Notify Moderator

Some people use little 12v automotive bulbs to drain lipo batteries used for RC toys. One guy had quite a few on a board and said it put out a lot of heat.

I think what you propose will work to some degree. Maybe you can set a chair over your heat device. Like when someone puts a few campfire coals under a chair.

Flute Man

Payson, Arizona

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Posted: 03/26/20 04:08pm Link  |  Quote  |  Print  |  Notify Moderator

DarkSkySeeker wrote:

Flute Man wrote:

I have a 12 V 300 W heater in my rally compartment. It draws 25 A so figure yours accordingly.
Electric heaters have a very simple formula.
Watts Divided by volts equals amps.

Did you buy it online? If so, could you share the link?

It came with my motorHome. Sorry


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DarkSkySeeker

Freestone, California

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Posted: 03/26/20 05:15pm Link  |  Quote  |  Print  |  Notify Moderator

time2roll wrote:

You will be lucky to keep the 12v battery charged and burn propane running the furnace.

My idea is to run the heater directly from stand-alone solar panel(s), not via the RV batts.

pnichols

The Other California

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Posted: 03/26/20 06:45pm Link  |  Quote  |  Print  |  Notify Moderator

DarkSkySeeker wrote:

Is there a heater product that can run off the 12V that comes directly off my portable solar panel? This would have to be something that can handle unregulated power that might peak up during bright sun and drop very low when a cloud passes by.


You might want to locate and buy one or more of these 120V 155 watt "personal heaters" that can keep one person per heater toasty if it's close to them and aimed right at them.

It has 3 settings - one fan-only setting for cooling and low and high heat settings. It consumes about 155 watts on it's high heat setting. We use a couple of them at home to warm us when sitting so we don't need to have the house furnace set so high. On RV trips I take both of them along for emergency heat boosting in specific areas of the coach when on hookups.

I have run one all night off a 300 watt pure sine wave inverter - fed by one Group 31 12V AGM battery - to heat the interior of my truck when sleeping in it overnight at a remote campsite. The two I have are several years old and have been super reliable.

https://www.ebay.com/p/1524623641?iid=274188423300


Phil, 2005 E450 Itasca Spirit 24V

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