Volkswagen: battery for 71 bus, trickle charge, storeage

Question
My newly aquired 71 camperbus battery died. I am trying to replace it.  I currently have not been able to diagnose some sort of Generator problem, (lite comes on and it dies after about 10-20 miles) anyway.... seems only tiny little things will fit past the engine parts.  Also we are questioning how many CCA's we should need/want on the new batt.  Current was 525 or 550 I think.
Do not want to over work Gen. more than neccesarry, however want as much power as poss. I guess.  Also going to be storing it WITH new batt. for winter in heated space, with potential to either trickle charge battt. and or move it back and forth every week or two.  What are your suggestions for type/size etc. batt. (are they usually the very smallest square sized batteries in them?  How many CC Amps usually needed? Lastly any advise for winter storeage on old vehicle I have rarely used since obtaining?  THANKS  Michelle

Answer
Hi Michelle,

The first thing you should do is check the voltage regulator.  It is located behind the air cleaner.

This is most likely the culprit.

Clean up all the wires that connect to it as well, it can be simple as a corroded terminal.

Let me know how you make out.

Ron