I need to heat the enclosure for a resin 3D printer.
I have a W1209 temperature controller, and looking at this small heater unit : heater link
The site says 12V 300W which I assume means it will draw 25amps.
Is there a way to reduce the current draw & heat produced by a heater like this ?
The printer has a small enclosure, and I think around 60W would be more than sufficient ( based on the heat produced by a 60W incandescant bulb ).
Temperature in the enclosure only needs to be around 25-30C and our room temperature is around 20C
alternatively, should it work just as well if I use 2 x printer hotend heater elements ( 12V 40W x 2 units = under 7 amps ) mounted in front of a small fan to push the heat off the elements and circulate in the enclosure ?
It looks like your small heater includes a fan and a temperature sensor and control. I guess that you only have to set the desired temperature, somehow, and provide a powerful enough psu. OTOH the lack of any detailed information discourages from buying such an obscure part.
A PTC heater will control its own temperature. As the PTC heats up the resistance increases resulting in a reduction of wattage. This will become "stable" at some predetermined (by the PTC) temperature.
If you limit it with a resistor it will take some experimentation as you cannot simply calculate the resistance at 300W due to the PTC's non linearity.
So yes you can reduce the temperature but you will loose the inherent control of the PTC.