Just in case people wanted to know if this gain is worth the hassle, read below.
If you normally get 50mpg, and gain 10%, that's a 5mpg gain.
10,000 miles @ 50mpg cost you 200 gallons of gas at $4 per gallon that's $800
10,000 miles @ 55mpg costs you 181 gallons of gas at $4 per gallon is $727
a savings of $73 per 10,000 miles or $7.30 per 1,000 miles
This doesn't account for the charging cost on the grid either.
For my short term testing it cost me $0.03 per day to charge my battery, but i have a very small 10 mile daily commute. 5 miles each way.
So if you do drive 20,000 miles and can get 5 years out of the battery pack you
would save $730 less the charging cost. Hopefully your new batteries, copper cable, switches ect. cost less than this. Most guys that try this have a free supply or cheap supply of deep cycle batteries.
This doesn't take into account the benefit of bragging to friends, saving the earth
or enjoying ecomodding as a hobby. Also if one were thinking about buying
a new car to get better gas mileage this option may be worth it. Or if your MPG is already low this mod will pay for itself more easily.
Take a 10mpg vehicle that uses 1000 gallons over 10,000 miles. That's $4000 in gas, with a 1mpg boost you save 91 gallons, or $364 dollars.
Although, if you're getting 10mpg you should really find a better gas mileage vehicle.
