With a balance board you can balance charge a number of batteries like Mike says. I only use the ones with fuses on both the main power lines and with polyfuses on the balance lines. Like Mike,I individually check each battery before I connect them.
Unless using XT60 or Deans your probably going to need adaptor leads and It's helpful to have balance extension wires too, depending on how generous they are on the batteries.
I charge 4 x 5000mAh packs on this at 7.4 Amps (my power supply is the limiting factor here) I have done this will all my batteries since day one and they have always been balanced when checked afterwards.
John, I charge mine in an ammo can on its side, with the lid off on the concrete floor of the garage. If the worst happens I'll loose all batteries and the balance board, but the ammo can should direct the flames outside as I leave the garage door slightly open.