Dropping charge between alternator and battery. Car won't start.

[snapdragon]

It doesn't have to be the same brand, just enter the VW part number for the same capacity of the battery of the one you have. The car won't know the different, it only needs to know it's characteristics. If the new battery is the same size as your old one, just change the serial number by one digit (+1) and it will just reset all counters and know it's a new battery.