[jhautz]

Is this the Schulze 636 we are talking about here?

If so, according to the data sheet I found, the first output can charge up to 11s lipo and the second output can do up to 3s lipo. If this is the correct charger it sounds like you can do this either way. Charge a 2 packs, one on each output, or charge in series as one pack on one output. It just depends on how you want to set it up.