The State Ports Authority's Wando River terminal is also in Mount Pleasant. Charleston is the largest city near Mount Pleasant, although Mount Pleasant is quite large in its own right. Here is a map of the Charleston area.
Group means battery physical size, ie group 24 and group 27 as mentioned earlier. Its CCA/MCA rating that counts. I have two batteries, one is 1000 cca's the other is 600 cca's (cold cranking Amps). The 1000 is the starter battery, the 600 runs accessories and is a back up starter. The higher the CCA rating, the more starting power you have. This is oversimplifying it but it gives you an idea of what a battery rating means.
By the way, 16340 rechargeable li-ion battery is also called RCR123. It is the same size as CR123A primary (non-rechargeable) cell. First letter R means rechargeable. And again, if word Protected is printed next to 16340 (or RCR123), battery will be longer than regular CR123A by 2.5mm to 3mm.