Try driving one below a certain speed for more than 20 minutes and see what happens.
This is a vehicle that takes gasoline as a power source, there is no plug for a charger. I understood it only stores power generated from braking but if they are powering it from the battery for low speed operation, they are obviously running the gasoline motor in a way as to produce more energy to motivate the car, and sucking some of that off to charge the battery. Nevertheless, the battery does not produce power out of thin air. It either comes from regenerative braking or from the gasoline engine. Thus the battery capacity does not need to be as large as a fully electric car. I still think it would be quite easy to subsbreastute lead-acid batteries for the NiMh traction battery, buttuming you wanted to preserve the gas engine and such.
The significant thing here is that in the Prius or other hybrid you have a complete vehicle chbuttis with an interior, carpet, seats, etc. and powertrain that is fully electric. 80% of the work is done for you in building an electric car, all you have to do is gut the gas engine and traction battery and the Toyota computer, and put your own batteries in, configured to supply the power that the Toyota traction motor requires, and add a charger.
Clearly in old used Priuses, the traction battery and gasoline engine will wear out long before the electric traction motors do. It is really a ripe candidate for a conversion once that happens, since you will be able to get them for practically nothing, and nobody is forcing you to replace their guts with Toyota's rather expensive hybrid system.
Ted
