wasted-heat

tom cloud cloud at hagar.ph.utexas.edu
Thu Sep 19 23:57:55 GMT 1996


        [snip ]

>the peltier cells are widely used in automotive drink-coolers and they
>are really

saw an article once where someone attached a modified grill to the back
of the car and used the heat from the exhaust to cook a meal whilst
driving.

>well , I'd be more careful about estimating the ele-power-consumption of
>my car
>only the front lights are a little above 900 watts :)
>(it  helps finding the way ;) )
>the audio sys eats up some 200-300 W the stand-heating 40-200 W
>the seat-heating ? only saab knows ( I found it in a saab 900 )

dunno where those figgers come from.  P=E * I.  A headlight bulb
is typically 50 watts.  I = P/E, therefore about 4 amps per headlight.
About 2 amps for clearance / stop / turn lamps (each), so for two
headlights and 2 clearance / turn lights, maybe 150 watts or about 12 amps.

The power consumed by audio systems is minimal: maybe 200 mA for
a tape drive motor.  Most power is for anything that lights up -- like
incandescent lamps or LED's.  Now, when you're making volume, that's
a different bag o' worms.  But 300 watts?  What I was trying to say
in the first part is, most of the wattage (like the 300 watts) will
be used in the power amp -- and most of it (class B amps are about
75% efficient) will go into the speakers.  You listen to that long
and you'll have to correspond by writing or sign language 'cause you
won't be able to hear.  Besides, never seen an OEM system that made
300 watts -- didn't say there weren't any.  Most systems make maybe
10 or 20 watts.

What I've observed for electrical power draws:
        headlamps       50 watts        ~ 4 A
        exterior lamps   10-20 watts    ~ 2 A
        interior lamps   10 watts       ~ 1 A
        dash lamps       2 watts        ~ 200 mA.
        ignition coil   50 watts        ~ 4 A (intermittent)
        radio           2 - xx watts    ~ .25 amps (no volume)
        tape deck motor 2 watts         ~ .2 A
        starter        1800 - 3000 watts ~ 150 - 250 A
        fuel pump       24 - 120 watts  ~ 2 - 10 amps
        blower motor    ( dunno )
        computer        ( dunno )

Tom




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