PDA

View Full Version : some Fun W/Math



Dr. Jerryrigger
02-27-2009, 07:41 PM
I was playing around with some numbers last night and came up with this...
So my car gets about 25-27mpg highway (with out any tweaking) So to drive at 55mph for one hour it uses ~2gal of gasoline
Gasoline energy= 33.652kWh
for equivalent power I would need that *2 for the one hour= 66.304 kWh
=66304Wh at a 50% efficiency of electrolyzer = 124,608 Wh
/12V=10,384 Amps for one hour
okay so 50% efficiency is on the low side so lets try 75%
X*.75=66304 and X=~88405watts
/12V=7367Amps
I may be off on this # but for some reason it's in my head that 7.5mmW is 100% efficiency. If I'm way off on this disregard what lays below:
75% of 7.5mmW=5.625mmW
88405W*5.625mmW=497278.125ml per min=497 L per min
Holly crap I would need a lot of batteries so many it would greatly reduce gas mileagen which would require more batteries which would reduce gas milage which would.........and I drive a small car.
Okay so lets take a look at batteries.
a battery discharged in a hour give you 80% of it's Ah rating if your lucky
So I found specs for some bat. that weighs 71lbs. and gives 244Amp Hours over 20 hours... so let us cut that down to 80% 244*0.8=~195 amps for one hour
So for a needed 7267Amps I would need 7267/195= 37.26666 Batts, but lets round up because 80% is probable high
38 bat. at 71lb.=2698lbs. which is more than my car weighs.....

H2OPWR
02-27-2009, 08:57 PM
I was playing around with some numbers last night and came up with this...
So my car gets about 25-27mpg highway (with out any tweaking) So to drive at 55mph for one hour it uses ~2gal of gasoline
Gasoline energy= 33.652kWh
for equivalent power I would need that *2 for the one hour= 66.304 kWh
=66304Wh at a 50% efficiency of electrolyzer = 124,608 Wh
/12V=10,384 Amps for one hour
okay so 50% efficiency is on the low side so lets try 75%
X*.75=66304 and X=~88405watts
/12V=7367Amps
I may be off on this # but for some reason it's in my head that 7.5mmW is 100% efficiency. If I'm way off on this disregard what lays below:
75% of 7.5mmW=5.625mmW
88405W*5.625mmW=497278.125ml per min=497 L per min
Holly crap I would need a lot of batteries so many it would greatly reduce gas mileagen which would require more batteries which would reduce gas milage which would.........and I drive a small car.
Okay so lets take a look at batteries.
a battery discharged in a hour give you 80% of it's Ah rating if your lucky
So I found specs for some bat. that weighs 71lbs. and gives 244Amp Hours over 20 hours... so let us cut that down to 80% 244*0.8=~195 amps for one hour
So for a needed 7267Amps I would need 7267/195= 37.26666 Batts, but lets round up because 80% is probable high
38 bat. at 71lb.=2698lbs. which is more than my car weighs.....

Good or bad math. That is why we can not run a car off HHO. Just use an electric motor to power your car and you would be better off.