Lo-tech plugin or 40-80% MPG boost

I noticed a couple things and I believe a 40 to 80 percent mpg boost is attainable.

First- PCer tripp stated that the current Prius battery size is determined by legal/patent restrictions of Cobysas. So it is not engineering that determined our Prius battery size.

Second- a Prius salavage business operator piggybacked a Prius battery to a Prius and got 72 mpg (a 40% increase over 50 mpg) http://www.autobeyours.com/PHEV.htm

If you could make the piggyback battery set up a plugin 90 mpg could be attainable.

Also if salvage batteries are hard to come by a lead acid arrangement could work.

So for less than $2000 you could turn your Prius into a 70 MPG'er or for less than $4000 a 90 MPGer.
A charger that could do the job costs about $1500. That charger is very sophisticated and a simpler one designed just to charge a Prius could be much cheaper.

I won't be hacking my Prius until it is no longer my wife's car but I encourage others in this direction.

 

The salvage shop operator was able to piggyback the battery and not set off any trouble lights. He considers this his major accomplishment. Also a Prius hacker group has come up with a printed circuit board to accomplish this task much easier for anyone who chooses to follow.

The link I provided has a picture of two ways he piggybacked the battery. Space is compromised, such is the life of Hot Rodders. It is close to fitting in the space above the spare though and a lead acid arangement would offer more customization of battery pack to preserve stock appearence.

Lead acid may prove to be the winner in the end. A new enhancement of lead acid is on the horizon by Firefly:

"Performance improvements in lead acid batteries are realized through better utilization of surface area, he adds. The overwhelming restriction to lead acid battery efficiency to this point has been the lack of interface area between the active chemistry and the electrodes. Today, the chemistry is capable of delivering approximately 170 Watt Hours per Kilogram (Whr/kg), yet lead acid batteries only average around 30 Whr/kg. Up to now, achieving a higher surface area within a given lead-acid battery box required the addition of more and thinner lead electrodes. However, lead electrodes corrode, so increasing surface area by putting thinner lead electrodes in the battery increases corrosion and decreases battery life. "

“What people don’t appreciate is that the cost of the cobalt used in lithium-ion batteries has jumped from $40,000 to $60,000 per ton, and the nickel-metal chemistry has jumped from $10,000 to $14,000 per ton in the last 18 months due to China’s increased demand for stainless steel,” he says. Lead, on the other hand, has risen from $500 to $1,000 per ton. So while the Firefly battery may be slightly more expensive than a conventional lead-acid design in terms of dollars per kilowatt-hour, prototype units use half the lead. The next generation will use ¼ the amount.

The electrolyte in a lead-acid battery is a big resistor due to the distance the ions must travel between the grids. In the Firefly battery, this space has been reduced from millimeters to microns. As a result, the ability to both send out power and recharge is claimed to be dramatically better. “The Firefly battery has about seven times the recharge speed of a typical lead-acid battery, and its output doesn’t diminish if it is left discharged for any length of time,” says Ovan. This means the technology has potential for use in hybrid vehicles.