Max potion

[Martinek]

Hi can i use max potion on pokemon with energy but no damage counters? Thanks

[PokePop]

There is a ruling on a similar card in the "ex" version of the Compendium:

Q. Can a player use Pokémon Nurse on a Pokémon with no damage on it, but still discard the energy from it? Is removing Damage a condition of being able to play Pokémon Nurse?
A. Yes, you can play Pokémon Nurse even if there are no damage counters on that Pokémon, but you would still have to discard the energy if there were any attached. (Jan 22, 2004 PUI Rules Team)

[PokePop]

Sorry, update.
The most recent ruling, from the BW Compendium says "no".
So that is the one to go by.

http://compendium.pokegym.net/compendium-bw.html#210