Alternates Re: <VV> Electric cooling fan results

[Bruce Schug]

On Jul 30, 2007, at 1:59 PM, Tony Underwood wrote:

> 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.

Would a small lawnmower battery like this power a fan on an autocross 
car? If you had it thermostatically controlled or a toggle switch to 
turn the fan on and off, would this type battery run it enough to cool 
after a run?  It could be recharged in the pits.

Bruce

Bruce W. Schug
bwschug at charter.net