Battery Draining Rapidly - Any Insight?

My '92wagon with 160K miles is acting up again....the battery (replaced on 10/2012) is draining within 30 miles of driving.

 

I replaced the alternator in 12/2012 so I need to pull it and get it tested...but assuming it's OK, is there something else I should check?

 

Thanks for your input...I'm mechanical but admittedly, crappy at diagnosing electrical bugs.

 

Maybe you got a bad alternator or battery. Ive heard of a few people getting a crappy alternator that didn't last. I'd also check your ground lines and clean your terminals. It only helps to add a few more ground lines and it helps the car run smoother believe it or not. That's all that I can think of.

Yeah I got 2 bad alternators in a row out of autozone, first one died quickly, second one didnt die but only charged at 12.2 volts. The duralast alternators are made in eithec china or mexico. In mexico they can't solder, in china they use cheap bearings.luckily they have warranty

Measure the voltage reading across the battery terminals with the engine running . Should be about 13.5 volts . If that is correct then the alternator is charging ok . Problem might be a current drain from battery when engine switched off . Disconnect positive lead from battery and connect ammeter between disconnected positive lead and +ve battery terminal . Current draw should be no larger than say 50 mAmps . If you are drawing in the Amps range then go to fusebox and disconnect each fuse in turn until you find which circuit is causing the drain .

measuring voltage at terminal ends while the vehicle running is only half checking the alternator..... one of the diodes could be bad and it may be putting out low amps...... thats why when i test an alternator i ALWAYS put the amp lead on the main wire coming from the alternator....

Thanks for the direction and good advice. I suspected that the cheapo auto zone alternator may well be the culprit, but I'll definitely try the suggested tests as well.

This will be good practice to start developing my knowledge of electrical systems.

 

Again, thanks for taking the time to reply to my question.

A good alternator will read 14.2- 14.4v while running no matter where u check it on the positive wire or battery, anything less and its suspect. As far as amperage output you could run the lights and heater and your 14.4 volts should keep up close (within a volt). Those bad alternators go bad fast when heavy amperage is used. a good charged battery will be about 12.8v not running.