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So, I have had a frustrating problem for the last couple of years. In summary, it's an 87 Monte Carlo SS, 383 stroker, with a 105 amp alternator. I'll get a brand new Optima battery, the car will start once or twice and the battery is dead/fried and has to be replaced under warranty. So the car keeps eating batteries and I have replaced the alternator three times now. I'm unsure how to troubleshoot this if anyone has some guides, flow charts, or ideas?
 

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My best guess..... the alt pig tail is wired incorrectly or you have a huge drain somewhere. Something's draining the battery to what I called dead beyond repair! Doesn't matter if it's new or old.... if the battery gets drained to zero volts a few times it's usually toast, just a matter of time. Sometimes you can bring them back with a pulsed charger like C-Tek.

After the battery gets fully charged, does it go dead in a matter of days? If so, does the alt case get hot? If the above is true..... your pig tail is wired incorrectly or you've got a short somewhere in your sense wire
 

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So, I have had a frustrating problem for the last couple of years. In summary, it's an 87 Monte Carlo SS, 383 stroker, with a 105 amp alternator. I'll get a brand new Optima battery, the car will start once or twice and the battery is dead/fried and has to be replaced under warranty. So the car keeps eating batteries and I have replaced the alternator three times now. I'm unsure how to troubleshoot this if anyone has some guides, flow charts, or ideas?
print and perform these tests..

http://i.imgur.com/WMDprhm.jpg

test 5 might be hard to perform as i don't think there is an underhood fuse box or perhaps even a power distribution stud in the engine compartment.

perform this test on a different car first.. so you what good results look like..

post them by number with some pictures of your engine compartment.
 

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You need the proper equipment to see if the alternaor is actually putting out current wen the vehicle is running and also to check if there is any significant draw on the battery when the car isnt running. An inline amp meter with a shunt is what is required to properly test. Alternator charging voltage is not alway an indication of proper current output.
 

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Being able to measure current from/to battery would help a lot. I've had a no-name multimeter with clamp-on current probe for many years, and it works great for determining current draws, alternator operation, etc. Obviously it must be able to measure DC current. I say this because many clamp-on meters are AC only.

They all look similar to this one:

 
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