I have been dealing with this issue since last summer. I Charge my battery with a trickle charger and put it in the car. Sometimes it last about a month or so, but then eventually ill drive somewhere go to turn it on and it wont start. I tuern the key and not even a click. It has a brand new alternator and battery in it and both have been tested good. i replaced wires to the alternator and still the same problem. there is no draw when the car sits that kills the battery it only dies when i drive it, which doesnt make sense to me. The radio isnt hooked up, and even when i dont use the wipers, lights or blinkers it still seems to die while driving, i just dont understand. Please help!

 

its possible the alt is no good the diodes can go bad but still make the connection and test good whered you get it? is there a warranty?

 

Got it from advanced auto parts. Dont think there is a warranty, but ill have to try a new one i guess.

 

Is the alternator putting out in the 14 volt range, when checked right at the alternator? Don't trust the dash gauge.