battery replacement/bigger battery?

I think the consensus would be that the transaxle and the inverter would cost more to replace than the battery. If your battery were to "die", your mechanic should be able to find a salvage yard Prius with a battery you could swap in, saving a couple of thousand dollars. We are talking about the "big" battery, not the small 12 volt which is used to boot the computer(s) in the car.

I don't know of any aftermarket replacement batteries for the Prius.

There are a few aftermarket Plug-In conversion packs that can be added to your Prius. These work with your current nickel battery, rather than replace them. They typically allow for you to plug in and charge up the car and offer up to 25 miles or so of all electric driving. Engineer and Hymotion make such kits. You can also visit http://www.lusciousgarage.com/ for the kit they use. Here's their link within their site. http://pluginconversions.com/how.html

There is also a Plug-In Prius coming out in 2012 which can provide about 12 miles of all electric range, or combined with your normal Prius operation to make it more fuel efficient.

 

Pay a Prius technician (usually at a Toyota dealer, but there are independents) to completely check out the car before you buy it. If a dealer is selling this car without any warranty, have it checked by a different dealer.

 

The high-voltage hybrid battery is not too big of a concern. There have been a few instances of failures, but they've been providing really nice service life in most cases, especially on the generation II (2004) and newer Prii. It's usually something you never need to mess with as long as nothing strange happened in its past. Overall, the Toyota hybrid drive trains have been more reliable than the power trains of most conventional cars. The trouble posts on the forum may look discouraging, but for each person who posts on here with a problem, there are probably 100's of other Prii running around out there with no problems whatsoever (mine included).

There are some plug-in conversions but they supplement the existing battery pack and are usually more expensive than the original pack. Most people don't bother with them. Here's another source of plug-in conversions. GreenGears

The small, 12-volt booting battery is somewhat of a concern, as the original equipment items only tend to last 3-6 years and don't provide very long power reserve for running accessories. Many people are replacing them with deep-cycle batteries such as Optima Yellow Tops that last much longer and are able to survive discharges better.

For improving MPG, learning and practicing eco-driving techniques are pretty effective without the cost and complexity of a plug-in conversion.

 

Suprat04r - What are you thinking of buying - what year and how many miles?