12V 250Watt electrical load

[yngndrw]

I'm looking for suggestions as to what I can use for an electrical load for developing a simple PWM controller. The controller will be used for Peltier devices and will supply up to 12V @ 250Watts. It should also be very low cost.

A few light bulbs would have been ideal if it was at mains voltage, but it is not. Any suggestions ?

[Al_The_Man]

What about a suitable wire wound resistor?
Or to obtain 250w version, buy a replacement ~1KW heater element coil and cut off at the required resistance.
Al.

[vger]

Another option would be to use 12V automotive or RV bulbs. RV bulbs are available in various wattages and you can parallel them to come up with the load needed.

[yngndrw]

Thanks for the replies.

I had thought about automotive bulbs, but the highest rated ones I could think of are 60Watt headlight bulbs which would require 4. As such they are a bit expensive for me.

The issue with a large resistor was cooling, however the heater element idea could be perfect for me. I'll just have to find one rated high enough at 12V, but I'm sure I'll be able to.

Thanks again.

[Al_The_Man]

Depending on what your application is, the problem with lamps the resistance tends to change more radically with temperature (brightness) not so much with a suitable wattage resistor where the heating effect would be much higher than your application needs.
For 12v 250w the resistance would be .6ohms, a 240v 1kw heater coil would be around <60ohms, so you may have to chop some short pieces and parallel them, a good meter should help.
Al.

[yngndrw]

Originally Posted by Al_The_Man Depending on what your application is, the problem with lamps the resistance tends to change more radically with temperature (brightness) not so much with a suitable wattage resistor where the heating effect would be much higher than your application needs. For 12v 250w the resistance would be .6ohms, a 240v 1kw heater coil would be around <60ohms, so you may have to chop some short pieces and parallel them, a good meter should help. Al.

That should do perfectly for me, thank you very much for the idea and help.

I don't need to to be very accurate anyway as it is just to test a PWM controller across it's full range.