Alternates Re: <VV> Electric cooling fan results

[Tony Underwood]

At 02:57 PM 7/29/2007, FrankCB at aol.com wrote:
>
>To give us an idea of just how much electric  current is needed, 14 hp is
>equivalent to about 10-1/2 KW.  If we try to  draw this much from a 12 volt
>battery it will equal a current flow of almost 900  amps.  This is 
>probably about
>FIVE times what the Corvair starter draws


Just FYI...  a friend and I were playing around with some of the 
things he uses at work (maintenance on locomotives for 
Norfolk-Southern RR) and he had an ammeter that used shunts for 
scaling that would go up to 1000 amps in stages... we used the 100 
amp shunt and just for funzies we put it inline with the battery in 
my 140 hp ragtop.   The meter bounced up pretty high when the starter 
first engaged at the beginning but while continuously cranking the 
engine (with the coil wire off) the starter was drawing ~58 amps 
while battery voltage was hovering around 10.5-11.

It doesn't take that much to crank a 'Vair engine in decent 
shape.   This is likely how I got by with running a lawn & garden 
tractor/lawnmower battery ($17.95 at Wal-Mart) in my Spyder for two 
years Back When on a lark when the type-51 batteries were selling for 
50 bucks and I was between paydays and a cheapskate to begin 
with.   The mower battery fit the battery box easily and it had 
plenty of current to crank the hell out of a Corvair engine.    Just 
thought I'd mention it.


Now, powering an electric fan hard and fast enough to adequately cool 
an air-cooled engine is another matter entirely.



tony..