Parallel Charging is a safe and easy way to charge several batteries at one time. If you have a four button multi-chemistry charger (similar to the Accucel 6) this Hobbyking parallel charging board makes it easy for you.
Before you go out and start charging lipos be aware that all of the standard disclaimers and warnings for charging/storing and using lipo batteries apply. Spend some time on the Google machine and familiarize yourself with lipo safety and advanced charging concepts for parallel charging. Familiarize yourself with the risks and manage the risks. Lipo fires are real and do happen. Ultimately you will be the one held responsible if an accident should happen. Play and charge safely.
Here's a great article about parallel charging:
And another good article about lipos in general:
Hobbyking Parallel Charging Board for 6 packs 2 - 6S XT60
Here's a pic of what the board looks like as delivered from Hobbyking:
The board works fine as delivered from Hobbyking but I chose to clip off the XT60 and soldered on a couple of banana plugs so I could plug the board directly into the charger.
Here's the board hooked up and ready to go on the Accucel 6
The Accucel 6 and the ECO 6 both hooked up and charging batteries.
Pulled back a little to overview the whole setup.
There are plenty of other ways to accomplish parallel charging with both of these chargers but these boards make it easy. Just make sure the voltages of the individual batteries are fairly close (within two tenths of a volt seems to be working well for me), only charge batteries with the same amount of cells together and follow all charging precautions as normal. Using these chargers, you will not charge multiple batteries super fast but at least you can charge and save time by charging a bunch at once. Charge safely!