You can use 3 cells. If membory serves, I measured around 9 amps peak with 3 cells on the 0808 and 10 x 4.7. You're only drawing 7 amps at full throttle with 2 cells, and hovering around 4 amps.

It's fun, and you should try 3 cells at least once on a shocky and Nippy. It's too much for me to be accurate in our small gym though.