What about power resistors from ebay?

[001]

Hi!

Is aluminium housed power resistors from ebay usable?

[ChrisLX200]

Usable for what? - fishing weights?  Need to be a bit more specific, but I can say you need a big extra heatsink for a resistor like the one pictured if you hope to get anywhere near the rated 100w.

[HighVoltage]

Usually when I need to use 50W or a 100W power resistor, I also need reliability.
So, I am using good quality power resistors only from VISHAY, OMITE or DALE.

[ChrisLX200]

This is a 50w (claimed) 1Ohm resistor, it's sandwiched between the two heatsinks shown. If I put 10w into it the temperature rises to 65degC with convection cooling, I have yet to test using a fan how much power it can dissipate with forced air cooling. Arguably these heatsinks are far too small for the power rating.

[001]

This is a 50w (claimed) 1Ohm resistor, it's sandwiched between the two heatsinks shown. If I put 10w into it the temperature rises to 65degC with convection cooling, I have yet to test using a fan how much power it can dissipate with forced air cooling. Arguably these heatsinks are far too small for the power rating.

Thanx! Best answer 

[Ice-Tea]

My guess is at least some of these have this inside:

[DerekG]

Is aluminium housed power resistors from ebay usable?

Ask for the spec sheet & then test it to the max if you need the entire power dissipation rating.

Run it for hours on end to check that it survives.

If you only want to run it at half of the power rating, then it will probably be fine. Again test it for many hours/days just to make sure.