So lately I have woken up to a dead battery a couple times. At first I thought it was just the -16* mornings, but it even did it on a 30*+ degree day. So I grabbed the optima red top I was going to use in my Sonoma, which was like 6 months old and never used to start a car, so brand spakin new. Put it in, gave it a charge and started it up. I figured I was all good to go now. Well on the way home from work, I see smoke coming from the hood and it stinks like rotten eggs (overcharged battery smell). So I pull over, pop the hood and steam is coming from the red top. wtf? So I get home and the battery is warm and still steaming. Next morning it started ok and got me to the airport for my trip. Come back from the trip (4 days later) and the battery is COMPLETELY dead...dome lights won't even come on (what a great surprise that was!). So I get a jump and get home without an issue. When I got home and shut it off, the battery was totally dead, the alternator was the only thing that got me home. First thought was the alternator was acting screwy, overcharging the battery or not charging it at all. Well the gauge on the dash never goes above 14v so it doesn't seem like it'* sending too much voltage. AmatuerZone tested the battery and can't even get a reading out of it. I also had them test the alternator/charging system...all tests ok...WTF? When his system tester put a load on the system, the headlights dimmed for a second....Any suggestions? I'm still leaning towards the alternator, but the tester says it'* fine....

I suspect the alt. A dead battery could be a number if things. The ELC pump running at night is good for that. But cooking the battery, there'* only one thing I can think of and that'* the alt over charging.

I've seen some goofing voltage reading difference from directly on the alternator output, versus at the battery, and at idle versus highway speeds. It almost sounds like the voltage regulator has failed and you boiled the battery. Here' some great info and a way to test if you own if you have a voltage meter (digital multi meter - DMM):http://info.rockauto.com/CarCareforC...Ch6SmplPgs.pdf

So I did some testing yesterday and am kind of confused...(these were tested at the battery)

Running at idle = 14.20-14.21 VDC
Fast idle (like 1500) = 14.20-14.21 VDC
Revved up (like 3k) = 14.20-14.21 VDC

It never moved from the initial reading at ilde no matter how many rpm. When I put a load on the system (rolled up the windows and held switch while windows were up), it only dropped to a minimum of 13.4 VDC. Also, I put in the battery that had been dying on me (the one before the optima) and it has not given me one issue for 2 days...wtf? Tonight I will test at the alternator to see if I get similar results..

In the testing area of the tech info there is a write up on testing the charging system and cables. Take a look and see if that helps out.