12V heater run straight from solar panel

[DarkSkySeeker]

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.

[time2roll]

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

[Boon_Docker]

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.

[DarkSkySeeker]

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?

[Flute_Man]

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.

[DarkSkySeeker]

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

PRODUCT LINK

[DarkSkySeeker]

DrewE wrote:
A big resistor that can dissipate a lot of power at 12V, sufficient to be a useful heater, is also a low-valued resistor, on the order of one ohm (approximately 150 watts). Making your own with resistance wire would probably be easier and less expensive than finding and affording a commercially produced resistor, marketed as such. Having a few coils wired in parallel is probably a good idea, too.

I'd think, for heating with solar power, that a solar water heater (as in a black pipe in a reflective trough or something similar) and a radiator of some sort would be more efficient and effective overall. The cost would probably be lower, too.

Agreed. My basic motivations are like this: I have these solar panels and what if I used them to generate ~500W continuously? And to avoid the complexity of a water heater based system, I wanted to be able to attach the 1 ohm resister(s) to create passive and unregulated heat.

[DrewE]

A big resistor that can dissipate a lot of power at 12V, sufficient to be a useful heater, is also a low-valued resistor, on the order of one ohm (approximately 150 watts). Making your own with resistance wire would probably be easier and less expensive than finding and affording a commercially produced resistor, marketed as such. Having a few coils wired in parallel is probably a good idea, too.

I'd think, for heating with solar power, that a solar water heater (as in a black pipe in a reflective trough or something similar) and a radiator of some sort would be more efficient and effective overall. The cost would probably be lower, too.

[agesilaus]

DarkSkySeeker wrote:

agesilaus wrote:
Even small 120 VAC heaters are 1200 to 1500 watts...

Thanks. Yeah, I was imagining a big resistor with a heat sink around it that would run passively. Perhaps I will find that.

That's what these electric heaters are. Resistor: NiChrome wire coil
Heat Sink: The surrounding air

The problem is that it takes many Joules to heat up that air and get ahead of heat losses thru the walls, air leaks and such. You can't sneak around the Laws of Thermodynamics.

[Ed_Gee]

Maybe something like this would work for you ....

12 Volt heat lamp

[DarkSkySeeker]

agesilaus wrote:
Even small 120 VAC heaters are 1200 to 1500 watts...

Thanks. Yeah, I was imagining a big resistor with a heat sink around it that would run passively. Perhaps I will find that.

[Lwiddis]

Never encountered a heater that would run solely from solar.

[agesilaus]

Even small 120 VAC heaters are 1200 to 1500 watts, that's a lot more than most peoples solar can put out. Heating is energetically expensive as is cooling aka air conditioning. But here are what is offered on Amazon


Be careful some are deceptive, the one 'universal heater' for example uses hot water from the engine block and the 12V is to run the blower motor.