Duel Battery setup & Wiring...

Ive got a 89 S10 Blazer im currently giving a renewed life

Ok, heres my question....

Ive got a high output Alt (115amp) and i want to run a duel battery system...1000CA/875CCA and a 800CA/675CCA

The 800CA is currently in the blazer and im going to buy the other in a day or 2....Ive figered out where and how to get the 2nd battery in under the hood....My Question is how would i go about Wiring the 2 batts too work with each other off my alt W/O spending 100bucks on a Isolator....

What i need to know is the pattern to use if anyone knows like..

Alt to Batt A then to Batt B

or

Alt to Batt A & Batt B

or

Alt to Batt A then Batt A + to Batt B - & Batt A - to Batt B +


Anyone??? Pls? :banghead:

Find a friend you has a GM diesel and look at it. OR go to a dealership and look under the hood of one. It will give you a good idea and something that you can actually see.