To set up a charging station for off-device charging of 3.7V Lipos, we have had good luck using a 13 port USB Hub like this one (lots available online if you search, just try to get one that plugs into a wall and can deliver at least 2A of current):

Then plug in each battery with a USB charger from Adafruit ($6 each):

There are other ways to make this work but this works well for us.

Take into account the total amperage of the chargers, and how many batteries you are charging. The USB Adafruit chargers charge at 100mA/Hr in slow speed or 500mA/hr in high speed. So if you plug in 13 batteries to charge at high speed you will need a USB hub that can support at least 6.5A of charging, which is a lot - the ones we find on Amazon tend to be 2A max. We tend to use slow speed for charging so we don't overload our strip (13 batteries requires just 1.3A at low speed, so a 2A charger is safe).