There are a few cordless RO polishers. However, none of them have enough power and battery life to actually be usable for more than just applying a wax or sealant.
As long as it can provide 3.7 amps of power then it should be fine. I don't know what kind of drain this would have on your alternator though... You might want to look into that before using it too much.
My alternator doesn't come into play at all, this unit is self proficient, its charged at home and AC power comes from the cig type lighter installed in the unit.......just not sure how long i can have power for.......