Re: [Phys-l] cars and physics

[brian whatcott <betwys1@sbcglobal.net>]

On 2/23/2011 1:07 PM, Edmiston, Mike wrote:
> /snip/  It seems to me the 12-volt battery would cost more than the 6-volt battery even if it didn't use much more material /snip/
> Michael D. Edmiston, PhD.
This looked like a straight forward technical or commercial question 
that might be answered readily by interrogating the price of comparable 
batteries in the market.

I was surprised and disappointed to find that comparing a 6 and 12 volt 
battery of equal  stored energy  and construction type, was not to be 
established by my headlong search among suppliers.    For the average 
car battery, people want $70 to $90. And that's not saying much.

I think that a reasonable figure of merit would comprise these factors:
 volts X amp.hours  X weight / cost.

That's something that could be evaluated at a supplier's shop with a 
bathroom scales, I suppose.   A sample value would be  350 watt.hour.lbs 
per dollar in that fine American customary unit mix.   :-)

Brian W