Originally Posted by Gambit7

Lithium-poly/ion batteries are pound for pound the cheapest batteries in the world. Over the long haul, they're MUCH cheaper then alternatives. Since they hold so much more energy, in reality you're getting a much greater lifespan. A 1000 cycle li-poly that can hold a laptop charge for 24hrs at MOST would need to be recharged after every 3rd use (assuming 8hr usage/day). That's nearly 10 years of battery life. No heavy metal battery can touch that. Also, the construction is more like playing with composites rather than playing with acids and heavy-metals.

As for the prices, they drop about as much as the computer industry does. When Li-poly came out, Li-ion became cheap. When A123 came out, Li-poly became cheap. This Li-ion/silicon battery will drive the A123 and Li-poly prices down even more. Once a reliable Li-Sulfur battery comes out we'll see ever more price breaks.

Battery manufacturing is one of the hottest small business startups in the tech. world right now. It's not very complex to do (you or I could actually build our own batteries if we wanted). Back when I was into R/C it seemed like there was a new Li-poly/ion manufacturer every damned day- each trying to beat out the other on price.

So I wouldnt worry too much about cost right now, they fall pretty fast. It's not a very exclusive technology... we're talking simple capacitors here. The biggest issues involve voltage regulation and cell-balancing, as lithium batts. are picky in those regards - but that has nothing to do with the cells themselves, it can be handled externally.

Btw, about 10 grand could get you a full A123 Li-Ion/poly plug-in hybrid conversion. With today's fuel prices, that pays for itself in 3-years. And that's not even factoring in the maintenance costs for IC motors, along with all the other fluids. Nor does it factor in energy retained from braking.

To take it further, you can also put your house on/off the grid by using the caps. in your car. Instead of the power company making energy you never use in off-peak times, it goes to your car. During peak-times (when you're at home) the car contributes back to the grid, taking the load off the power company. What happens?? Energy prices go down.
It's kind of tough to explain, but I saw a study on this (some of you might've heard of it).

One could get fancy and rig a true UPS for their home as well. Get efficient enough with good enough capacitors and you can take yourself off the grid entirely.