1640 brings around 9 batteries and 7 chargers to competition. This lasts us through finals if none break, and usually gives us one to loan to an alliance partner or opponent.
My number one recommendation is to clearly number all your batteries and chargers. We also test all the batteries beforehand with a CBA III and test any questionable chargers as well.
At competition, we use a comprehensive match chart which includes the match number, battery and charger numbers, and battery performance (namely actual starting and final voltage from the dashboard if they're abnormal). We also keep them all carefully sorted in the pit, using a standard sequence as well as checking the charge lights on the SC-600A (highest amperage). We've also purchased a
Battery Beak, which we've been using in the shop and plan to use in the pits. We looking to build a battery cart in the off-season, as the current setup is sort of table-space intensive.