Maker Pro
Maker Pro

Voltage and heating circuits?

G

Guntar Gunderson

Jan 1, 1970
0
I have a simple heating circuit that takes 16V @ 3.5A. I want to run
it on a 12V-48A/hr deep-cycle battery.

Now, I can get a DC-DC boost converter for $80, NBD.

What will happen (generally) if I hook it up to the 12 volt source?
It doesn't have any solid state circuits... it's simply a resistance
device; I don't expect it to burst into flames. Am I violating any
basic safety rules if I plug into a lower voltage?

Gunz
 
R

Rich Grise

Jan 1, 1970
0
Guntar said:
I have a simple heating circuit that takes 16V @ 3.5A. I want to run
it on a 12V-48A/hr deep-cycle battery.

Now, I can get a DC-DC boost converter for $80, NBD.

What will happen (generally) if I hook it up to the 12 volt source?
It doesn't have any solid state circuits... it's simply a resistance
device; I don't expect it to burst into flames. Am I violating any
basic safety rules if I plug into a lower voltage?
If the heater is indeed nothing but resistance, it won't do any
harm at all, but you'll get a drastically reduced heat output. I'm
way too lazy to do the math; if it's nichrome, the difference would
be exaggerated, because nichrome has some insane tempco of resistance.

But there's very little danger that you'll burn the house down. :)

Cheers!
Rich
 
J

Jasen Betts

Jan 1, 1970
0
I have a simple heating circuit that takes 16V @ 3.5A. I want to run
it on a 12V-48A/hr deep-cycle battery.

Now, I can get a DC-DC boost converter for $80, NBD.

What will happen (generally) if I hook it up to the 12 volt source?
it's simply a resistance device;

it will heat less powerfully by the ratio 12^2/16^2
which is 144/256, 9/16, or about 56%

but it's not that bad, lead-acid batteries are usually around 13-14V

ballpark 70-80%
 
J

Jasen Betts

Jan 1, 1970
0
Guntar Gunderson wrote:
be exaggerated, because nichrome has some insane tempco of resistance.

nichrome's tempco is very close to 0, stainless steel on the other
hand goes up quite a bit from room temp to red-hot.
 
F

F. Bertolazzi

Jan 1, 1970
0
Guntar Gunderson:
I have a simple heating circuit that takes 16V @ 3.5A. I want to run
it on a 12V-48A/hr deep-cycle battery.

Now, I can get a DC-DC boost converter for $80, NBD.

If you need more heath than half of the rated, maybe it's less expensive to
buy another battery to be put in series with the one you have and build a
simple, very low frequency, PWM controller, that will cost you about $5.
 
R

Rich Grise

Jan 1, 1970
0
Jasen said:
nichrome's tempco is very close to 0, stainless steel on the other
hand goes up quite a bit from room temp to red-hot.
Hm. I must have been thinking tungsten, as in bulb filaments.

Thanks!
Rich
 
P

Phil Allison

Jan 1, 1970
0
"Rich Grise is off his Drugs":

If the heater is indeed nothing but resistance, it won't do any
harm at all, but you'll get a drastically reduced heat output. I'm
way too lazy to do the math; if it's nichrome, the difference would
be exaggerated, because nichrome has some insane tempco of resistance.


** Ni-Chrome has a large tempco ??

News to everyone that has ever used any.

Wot a moron.


..... Phil
 
P

Phil Allison

Jan 1, 1970
0
"Rich Grise"
Hm. I must have been thinking tungsten, as in bulb filaments.


** Still wrong - dickwad.

In practice, the heat difference would be diminished compared to a simple
resistance - cos as the applied voltage drops, so does the resistance of
tungsten.



...... Phil
 
R

Rich Grise

Jan 1, 1970
0
Phil said:
"Rich Grise"


In practice, the heat difference would be diminished compared to a simple
resistance - cos as the applied voltage drops, so does the resistance of
tungsten.
Uh, yeah, that's what I just said.

Thanks,
Rich
 
P

Phil Allison

Jan 1, 1970
0
"Rich Grise"
Uh, yeah, that's what I just said.

** No dickwad - you said the direct opposite in fact:

" if it's nichrome, the difference would
be exaggerated, because nichrome has some insane tempco of resistance."


Piss off - IDIOT !!


...... Phil
 
R

Rich Grise

Jan 1, 1970
0
Phil said:
"Rich Grise"

** No dickwad - you said the direct opposite in fact:

" if it's nichrome, the difference would
be exaggerated, because nichrome has some insane tempco of resistance."
Yeah, and I stood corrected: After I was duly informed of my error, (see
upthread, if you're a man) I said, and you can look above, "Hm. I must
have been thinking tungsten, as in bulb filaments."

"Dickwad?"

Oh, well, guess you missed your Tourette's meds today.

But thanks for playing!
Rich
 
P

Phil Allison

Jan 1, 1970
0
"Rich Grise is a Fucking MORON "
Yeah, and I stood corrected: After I was duly informed of my error, (see
upthread, if you're a man) I said, and you can look above, "Hm. I must
have been thinking tungsten, as in bulb filaments."


** And that is where you made the second error - fuckhed.

Now you've made a third and forth time just to prove how thick you are.




...... Phil
 
R

Rich Grise

Jan 1, 1970
0
Phil said:
** And that is where you made the second error - fuckhed.

You can't insult me if you can't even spell "fuckhead."

Please go take your meds.

Thanks,
Rich
 
M

Michael Robinson

Jan 1, 1970
0
Guntar Gunderson said:
I have a simple heating circuit that takes 16V @ 3.5A. I want to run
it on a 12V-48A/hr deep-cycle battery.

Now, I can get a DC-DC boost converter for $80, NBD.

What will happen (generally) if I hook it up to the 12 volt source?
It doesn't have any solid state circuits... it's simply a resistance
device; I don't expect it to burst into flames. Am I violating any
basic safety rules if I plug into a lower voltage?

Gunz

Guntar, are you still there?
Just ignore the silly little flame wars. Phil has been doing that for
years.
Others have pointed out that heat from a resistor varies with the square of
the voltage, so you might be able to get by with a single 12 volt battery,
or two of them in series if you need more heat. But you don't have much
control over the amount of heat you're getting that way.
You could have an adjustable heater if you go with two batteries and a
simple controller, whereupon you could simply turn a knob and get just
exactly the amount of heat you need.
I googled "adjustable duty cycle heater controller" and found some that run
on 12 volts, but you would probably want two batteries in series (nominally
24 volts).
If you're comforatable with a soldering iron, you could make your own
controller -- it's a simple project, because all you need is a circuit that
turns on and off at a low frequency, like once a second. You adjust the
duty cycle and therefore the amount of heat.
We haven't heard back from you, but there are people here that just love to
offer their know-how on stuff like this. But you've gotta talk to us!
 
Top