The wife and I went out to my Jeep last night on our way out to dinner.
I put in the key, turned it on, and BRAAAAAAAAP!
The lovely sound of a solenoid *trying* to engage, and the battery not having enough juice to pul it in, and crank the engine.
I didn't leave any of the lights on, so, rather mystified, we took her car to dinner.
I put my charger on it when we got back home, and it proceeded to max out the charger at 10 Amps. I left it sit for a couple of hours, and when I checked it again, it was still pumping 10 Amps into the battery, so I let it charge all night long.
This morning it had dropped down to around 2 Amps, so I pulled the charger off, and checked the resting voltage.
It was enough to start the car with (barely!), and after it started I put the voltmeter back on the battery, and it showed 14.6 Volts, indicating the alternator was doing it's best to pump some charge back into the battery.
I let it run for about 30 minutes, and checked the engine off voltage, and it was back to ~11.5 Volts.....NOT a good sign.
Came back in the house, and started battery shopping on line.
Since this car has the 5.7 L Hemi, AND the Class-IV trailer towing package, it came with the heavy-duty cooling system, an oil cooler, a 160 Amp alternator, and the biggest battery I've ever seen outside of a Cat Diesel.
Since I always use a Deep Cycle battery due to the radio gear I carry, and Optima does NOT make a Group 72 size battery I was pretty limited in where I could buy a battery.
I wound up going to (UGH!) AutoZone.
BUT.....since I also needed a better charger, wiper blades for our 4 cars (it's rainy season out here), some washer fluid, and a bunch of other miscellaneous auto stuff, I went down the street to O'Reilly's to buy all the other stuff.
When I took the defunct battery out of the car, I noticed the end of the case by the positive post was HOT, much hotter than the other end of the case, and it was bulged out, so it looks like that cell developed a short, or very high leakage. This is probably a result of my leaving my Kenwood TM-D710 radio and GPS connected while I was gone for 3 weeks last year on a launch, and had a completely dead battery when I got back.
Standard automotive ("SLI", for Starting, Lighting, and Ignition) batteries do NOT take kindly to
1) Having a slow, constant drain on them
2) Being discharged and LEFT discharged for any length of time.
They're designed to put out a huge blast of current to start the engine, and then get recharged immediately.
Now here's where it gets interesting. When I took the dead battery back for my $12 core credit, there was an AutoZoner pushing a cart back in the store that he had previously used to help a young lady carry her stuff out to her car. I asked the guy if He could lug the battery inside for me, and he said he was "too busy".
So, I lug all 55 pounds of DEAD battery into the store by myself.
I'm in line at the "Parts" counter, where I had picked up the battery earlier, balancing it on a display rack. Then this guy behind the parts counter says "All of you people, the line starts over there", pointing to where the normal checkout line for people that get their own stuff go.
And there's about 25 people in line!
So I start to come forward so I can put the battery on the counter, and the guy goes "Go to the END OF THE LINE!". I say I just want to put the battery on the counter because its heavy, and he says again "Go to the END OF THE LINE!", and he seems to be getting testy.
I say again that I just want to put the battery on the counter because it's really heavy, and he spouts off "I don't care. GO TO THE END OF THE LINE. NOW!".
By this time some of the other people are saying to just "Let the old guy put the battery down, fer Pete's sake", and the guy starts yelling.
"NO! THE END OF THE LINE IS THERE! GO GET IN THE LINE!"
About this time (a good 15 minutes) I decided I'd had enough. I dump the battery down on the floor and state "KEEP the damn core charge. I will NEVER set foot in an AutoZone again!", and start walking out.
A couple of people applauded, and one of them held the door for me.
From now on O'Reilly's gets ALL my auto parts business.