Taught at a tech school, helped with the electric vehicle classes. Prius is the oldest most plentiful hybrid car, lots of them on the road and in salvage yards. If I was to do an EV conversion I would go with Prius batteries. Mind you, that you have to follow the proper safety precautions, but all electric car batteries I know of can be disassembled and the individual cells tested. Heat is what kills the battery cells, and you will find the computer shuts the car down when only a couple cells fail. The majority of the cells are still good, most of the time it is the cells in the middle of the pack that get less cooling. You can purchase failed Prius batteries, disassemble, test, and build a good battery, on an all electric vehicle, maybe you would link three batteries. One of the projects we did at school was an electric scooter with a bad battery, we changed the controller and used some Prius cells, got it up to 64 volts, used it in the pits at the races for several years, all most fast enough to hurt you.