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Car BAD-ery?

My husband left the car lights on and it killed my 2 month old car battery. Didn’t jump the car but took it to Autozone and had them trickle charge it overnight. When I picked it up they said the battery wouldn’t hold a charge. Took it home anyway and installed it in the car and it works. Checked it a few hours after and started without problems. So is it a bad battery or am I in the clear?

Give it a few days or a week. If it still starts then you are fine. No way to tell from here how good the battery is.

Or take it somewhere else to be checked.

However, note that when you totally discharge a car battery, it suffers some damage. Just once, you probably will be OK; more than 1 or 2, you can expect problems.


Bill has your answer. Second opinion is always the way to go.

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My two month old battery died yesterday.

I put it on a smart charger overnight and it didn’t take a charge.

When a battery does that, don’t trust it.

Get a new battery as I did.


I agree. It’s probably OK but lost some of its zing. Batteries in cars do not like to be discharged but one time shouldn’t kill it. Just because it starts the car fine in June though, doesn’t mean that it isn’t now at 75% of new. I’d have a regular shop test it before winter to see exactly where it is at for performance.

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If the previous battery tested at that store was from a Ford diesel and the tester wasn’t reset for your battery’s much lower Cold Cranking Amp rating it would indicate your battery was weak. But take the battery back to whoever you bought it from 2 months ago and without mentioning your husband’s unforgievable and totally ignorant mistake have them check it out “because you think it sounds weak when you crank the engine on some mornings.” If it tests bad they should give you a new one.


This is one time I’m going to disagree with @Tester. Although I don’t disagree as it is written, if @Tester did the trickle charge and it didn’t take a charge, I wouldn’t trust it either.

But @Tester didn’t trickle charge your battery for you, someone with far less credentials did the charge, so I would have to question their competence and the accuracy of their equipment, and that is the only reason why I don’t fully agree with him.

At this point, I’m inclined to think you are OK for now. Some damage was done and this battery won’t last as long as it would have. The first time it hesitates, replace it immediately or it will leave you stranded.

But there is one more thing, a two month old battery is under the 100% replacement period, it won’t be for long. If the retailer that sold you the battery is willing to replace it at no cost to you because AutoZone said it is bad, then this is the smartest economic alternative.

I have to disagree with some comments here. Drive the car and the battery will re-charge. Not to its fullest capabilities but good enough to keep starting your car

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Looking at the replies it seems the logical plan would be to drive around for an hour then return to the place battery was purchased and have them test it.

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Read this article, and then decide if the battery should be replaced.


Holy smokes this is an active forum. Thanks all for your input! Will take it somewhere else to test and bringing the change in the couch with me.

The battery did not fully charged on the trickle charger, the best way to tell is to ask how many cranking amps it has when it gets tested.

Just for reference my daughters battery was sluggish on starts, it only had 65 cranking amps! It would not have made it through the winter.
You can judge sometimes how good a battery is by the speed at which it cranks when starting a car, but my car the starter hits and it starts right up, load test showed the battery was at 400 amps cranking power, probably 7 years old so I replaced with with another 850 CCA when new battery before last winter.

Good luck getting a new battery so prepare for a struggle. I bought a lawn mower battery and the case heated up pretty good after adding the acid, plus I couldn’t get the thing to anymore than 70% of its rated cold cranking amps. I took it back and they tested it and said it was fine because the voltage and CCA were still showing good. I argued and finally reluctantly they gave me a new battery saying they wouldn’t be able to turn this one back in. Totally different story, warm not hot case, and CCA well over the rated. Obviously the battery was bad or at least not where it should be. I had the same thing with a one year old Walmart battery in a car that sat all the time. Wouldn’t take a charge enough to even turn the car over. They said it was OK when they tested it but finally replaced it after an hour of arguing.

So they are going to be very reluctant to replace a battery that isn’t really deficient and they are going to want to charge it up first to see if it takes a full charge. At any rate I think you really need a decent shop to check the CCA and state of charge and maybe give you a statement to work with. After the tests you can tell them it is only at 70% CCA or whatever and only taking 70% or whatever of a full charge.

I couldn’t in good conscience expect a free replacement for something I ruined .

Years ago, I had a horse that liked to lean over the fence, mashing it down. I put up an electric fence and powered it with a battery operated fence charger. The “hot shot” dry cell batteries lasted about a month and were rather expensive. I got the bright idea to replace the battery in my pickup truck and use the battery I removed from the truck to power the fence charger. I think that the battery from the truck would go almost two months before it wouldn’t power the fence charger. I would then connect the battery to an 12 amp battery charger for as couple.of days until the meter dropped below two amps and reconnect the battery to the electric fence charger. I got over two years from the battery before it wouldn’t take a charge. Now, it probably.didn’t have great CCA, but it did keep the fence electrified.

To digress, my girlfriend (now wife of 25 years) had a friend who owned horses, now she put me on an supposedly unrideable horse unknown to me at the time. The horse was ok with a saddle, ok with someone sitting on the saddle, but once the barn doors were opened all bets were off,That was pretty rude.

Now I just dug my knees in and held on to the horn as best I could after a couple of bronko maneuvers and trying to scrape me off on the fence and after 2 or 3 rounds about the corral, managed to calm the horse down to bring it to a slow trot and a stop in front of the owner.

Now she was ok he is man enough for you, and I was like what the hell kind of game are you playing,

Just saying sometimes you walk into things without a full understanding of what you might be dealing with at the time.

Gawd I love that story. (wow makes me wonder if wifey was in on it)

Edit adding @Triedaq just because you might enjoy this and have another tale to tell

Two questions. Did the horse ever learn? And, how did you tell the battery was working or not? Seems to me there is only one good way to test an electric fence and it’s not pleasant.

PS: I’ve never liked horses. Maybe it’s how they look at me but I just like things with off switches.

@Bing The fence charger had a mechanical device that would go “clunk, clunk, … .” Each clunk would send a charge through the fence. I assume the charger worked like the ignition system on the old cars with distributor points. My guess is that inside the charger was a coil and the primary side of the coil was fed by a switching mechanism so that when the switch opened, the magnetic field of the primary side collapsed inducing a charge in the secondary windings of the coil which was then sent to a wire at the top of the fence that was attached to the fence posts with insulators. The charger had a ground connection, so when the horse touched the wire, the circuit was.completed and the horse received a high voltage,.but very low current shock. I had put up the woven wire fence which took considerable labor, so I wasn’t about to let the horse mash it down. Driving the metal.fence posts into the hard eastern Indiana clay soil was.backbreaking work. To keep this car related,. I had a.1950 Chevrolet one ton pickup which I bought for $115 back in 1972. My neighbor had an old Massey-Harris tractor. He could.come borrow the truck when he the key was hung on a nail in the barn – and I.could.use his tractor when I needed it. The day I.was stretching fence on one side of the pasture and went.over to get the tractor, the battery was.dead. I debated about hooking my battery charger to the tractor battery, but I didn’t have a.cord long enough to.reach an electric outlet. Besides that, I would.lose’ waiting for the battery to charge up. I decided to try stretching the fence with my pickup. I put in first.gear(granny low) and the truck was moving forward. When I stopped the truck to see what progress I had made, I had the fence stretched so tight you could play tunes on it

@Barkydog. Here is my horse story. I got on an unfamiliar horse that I had never ridden and fell off and my foot was in the stirrup while the horse was moving. It seemed like an eternity before the manager of K-MART came and unplugged that horse.


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