Check out www.Progressiverc.com David Gray has an explanation on parallel charging batteries. It is very effective, it charges and balances the batteries equally. It makes your charger think it's charging a huge battery. For example, I always charge multiple 2S 5000mAh lipo. If I do four 2S my charger thinks it's charging one 20,000mAh battery. I set my charger to 20amps and the batteries are all charged and balanced in about one hour. I use the icharger 208b with a P350 power supply. It is no joke!