you shouldnt have any problems as long as both the battery's you are using all have good cells. they should all be around the same voltage. for example. if you have two, 2s 1p 30c lipo's. each cell should be about 4.20 volts. know if all your cells are running around there your're golden. dont panic if you have one battery that has one cell at 4.20v and the other at 4.17v. your still ok. but sense your running them inline i would make sure to balance charge them so each cell stays close to eachothers voltage as possible. if you have any more questions just hit me up.