The only thing I would take into consideration is the charge amps being delivered using the parallel chargers, most manufactures do not recommend charging lipo's greater than a 1C amp IE: 4480 mah Phantom battery should be charged at no more than 4.48 amps. That being said many parallel chargers, especially the ones that say reduced charging times will charge a battery at greater than the 1C recommended. Again that being said, I usually charge my 14.8V 4S 1800 mah racing quad batteries at a 2C amp charging them at 3.6 amps with no ill effect, keep in mind they are not "Intelligent" so I don't know if charging a Phantom battery at greater than 1C will have an ill effect on the P3's battery life or circuitry.