parallel charging board
This board allows you to hook up multiple batteries to your charger effectively tricking it into seeing a larger battery. So you can hook up 4 1300mah batteries reflecting 1 3S4P 5200mah battery.
With this board, you can hook up multiple batteries and balance charge them altogether. this allows you to significantly cut down your charge time.
Max current: 30A
Battery: 6 packs (same capacity & cell count)
See this post on battery C Rating
and this Post on Parallel & Series charging to learn more.