wasted-heat

[dzorde at aesprodata.com.au]

     I'm running 90/130W (low/high beam) in my headlights, a set of 150W 
     sealed beam for high beam and a set of 150W spotties.  Comes to 180W 
     at low beam (around town), switch on the high beam and you have 740W 
     (due to the purposely designed wiring the low beam stays on when the 
     high beam is switched on), then switch on the spotties (1040W) and 
     boy, you'll be able to spot a roo 20Km up the road before you hit it.  
     It does tend to flatten the battery over long periods though, the 
     alternator drops to about 9.6V @ 6500 rpm when everything is on.
     
     Dan        dzorde at aesprodata.com.au


______________________________ Reply Separator _________________________________
Subject: Re: wasted-heat
Author:  diy_efi at coulomb.eng.ohio-state.edu at INTERNET
Date:    9/20/96 9:40 AM


        [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