Notice the circular wire grill in the picture I linked? The good ones have a built-in fan to help cool the carbon pile. Yes, they definitely get hot! That type of tester can also be used to check the full-current output of an alternator by putting a load on the battery while the engine is running at a fast idle.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!