Wattage and Temperature Question

[AlistairW]

I am looking at a 12v project, and want to have heat a small box. I was looking at this site http://www.thermosensedirect.com/acatalog/silicone_rubber_mat_heaters.html - specifically the 12V Silicon Rubber Heated Mats and the 25mm x 50mm (1.24W). But how from this information can I tell what temperature the product would get too ?

Alistair

[Mick J]

I think you will have to email thermosensedirect for your answer, what temperature do you want the box to get to, how will you control it - possibly one of those cheap led dimmers or do you want temperature control in the box.  Lots of variables, ambient, insulation, run time, a small box is how big and made from metal/wood/plastic.....

Looks an interesting site and good prices, sorry for not being helpful.

[pete_l]

2 hours ago, AlistairW said:

 But how from this information can I tell what temperature the product would get too ?

There is no simple answer to this question as the final temperature will be dependent on the insulating properties of the enclosure. There is also the question of how long it would take for the contents of your heated box to reach its target temperature.

I think you will need to have this device controlled with a thermostat.

[The Admiral]

6 minutes ago, pete_l said:

There is no simple answer to this question as the final temperature will be dependent on the insulating properties of the enclosure. There is also the question of how long it would take for the contents of your heated box to reach its target temperature.

I think you will need to have this device controlled with a thermostat.

Indeed, the equilibrium temperature will be when the rate of loss of energy equals the rate at which it is added (i.e. 1 watt=1 joule/sec). The rate of energy loss would be difficult to calculate. For a start it won't be a linear function of the temperature difference between the inside and outside of the box.

Ian