Are you charging tx and rx flight packs, or full flight packs (for electric flyers). If you are only charging your tx and rx, then the 3A PS will do fine. If you want to do flight packs, then there are more potent ones out there. I got one from Pyramid for cheap $$ (for 20A power supplies, anyway).

However, if you are charging at home, it might go easier on your batteries if you just used the wall charger.

Bob