RV Repair: Electrical issue, shade tree mechanic, ford 460

Question
Hi Bill.

Thanks for answering my question. I changed the alternator and had to jump start it a few (5-6)times before I got it running. It ran for about 30 minutes, revving the motor a bunch of times during that time, but I turned off the key and it wouldn't restart again, the starter was clicking. Are there any other things like a regulator or something that should also be changed when swapping out an alternator?  I've worked on cars before a little (shade tree mechanic) and normally after changing someting like an alternator after starting up the car it would start to charge the battery immediately. It doesn't feel like that is happening here. I feel like I missed something. Can you help me at all?
I was planning on taking a trip from FL to NY next week, so time is short for me to get this working. I have young kids (4) and would hate to break down on a trip with them.  Thank you...

Also, what is the purpose of the second battery? What is it used for?
-------------------------

Followup To

Question -
I purchased a 1994 29' Coachmen running on a Ford 460 EFI. I have been starting and running it while in storage for the past few months since I've owned it and letting the generator run for 10 minutes at the same time as well. No problems. I recently took it out for a run and found the generator wouldn't run. It cranks, but won't turn over. It has a lot of power too and 3/4 tank of gas. When I drove the RV, things started acting funny with the electrical system, so I returned it to storage only to find out that it wouldn't crank over again, no power. I took the alternator out and had it tested and it failed all 3 tests it was given, twice. I got a new alternator, but haven't installed it yet. My question is, could the faulty alternator be a source of a problem with the generator not starting up? I did notice a small drip of oil from the generator, but I don't think it is the cause of it not starting (I read that if the oil level is low that it may not start) but I haven't checked the oil level yet.
Any suggestions?  Thanks....

Answer -
Dave:
The battery in the coach needs to be fully charged for things to work well. Running the truck and generator for 10 minutes is not nearly enough to put back the energy you took out starting it so eventually nothing will start. When you change the alternator charge both the truck and coach battery fully with a battery charger and see what that fixes,
Bill

Answer
Hi Dave:
An alternator was never designed to charge a dead battery, it is designed to keep a fully charged battery full. Charge the batteries fully with an external battery charger then check the battery voltage when the engine is running. You should have about 14-14.5 volts running and about 12 volts when you shut it off. I am pretty shure that in 1994 the regulator was inside the alternator.
Bill