Check for shorts..
Take off one battery cable,and hook a test light between the cable and the battery post..if everything is off,but the lamp lights,you have something short curcuited or drawing power that shouldn't be..that could be killing your battery..
It sounds like the battery just isn't getting charged..without any test meters,there are a few crude tests you can do to see if its charging..turn on all the accesiories,high beams,wipers,blower motor,etc...see if the lights get brighter,and the wipers go faster,and the heater blower speeds up, when the motor is revved up past idle..if so,some charging is taking place..
Also,when holding a screwdriver near the rear altenator bearing on the back of the case,you should feel a strong magnetic pull if the altenator is charging..
Both those tests wont tell you if the altenator is 100% (it can have 1 or 2 diodes out of the three blown,and still charge somewhat--or the rectifier bridge inside it can drain the battery if its faulty while the engine is off)..but it will at least give you an idea if its working at all..
At the 2 prong plug on the altenator,you should have 12V at both with the motor running,and only at the red one when its off..the other (tan or brown or white wire) should only have juice when the key is on,or when its running...that wire often F***ks up somewhere,and if no juice gets to the voltage regulator from it,it will never charge!..
I find a lot of those wires to that plug coroded in the harness between the altenator plug and the fuse box,or where they plug into the altenator itself -especially the tan,brown,or white wire for some reason
(at the firewall side of the fuse box..).,with NO visible damage..the wire just turns to powder at a random spot!..
.
Do some diagnosis..don't buy an altenator or any more batteries until your sure they are junk!..
I know I bought and installed MY share of them for nothing,only to find a bad wire somewhere later!
