[DonRotolo]

Li Ion are great, but brutally expensive in the capacities you'll be needing. Ditto NiMh, but a little bit less expensive. NiCd are OK, but don't have the instantaneous current output you'll need. Lead Acid are heavy, but cheap, plentiful and overall have great characteristics. There are many other battery technologies; depending upon your goals and finances you may select even something else (like a liquid sodium system).

The go-kart idea has merit. Just a controller for a typical 100 HP (75 kW!) motor is several thousand dollars, but for a 3 HP go kart they are far less costly.

Do research, more than Popular Science, as they tend to gloss over the practicality and are a bit 'gee wow, this is the future'. Great for the masses but kinda light for the person trying to implement it.

Don't let anyone talk you out of though - just approach it with a plan and go in steps. Oh, and post photos!

Don