I have a 2014 Mazda 6 GT. On Monday I went to start the car and I got nothing. The battery was completely drained. I jumped the car and drove it on the highway for about an hour. The same thing happened the next day. When I say I got nothing, by the way, I mean that even the little red/green light on the start button is out. I jumped it again and took it to the dealer. They told me the battery was bad and installed a new one (I had to pay 50% of the cost of the battery).
Now I understand that modern batteries do not react well to being completely drained, and I suspect that is what happened, although I have never seen a battery go south as quickly as this.
I am more concerned about why the battery drained. I am pretty careful about leaving the ignition in an “off” state when I leave the car (I pay attention when the car beeps at me as I am getting out and I always ascertain why). I can’t see how it is possible to leave the headlights on (and I hadn’t been driving after dark the day before anyway). My suspicion is that there is a short in the electrical system that is draining the battery. Anybody have any thoughts on this?
Batteries eventually go bad in exactly the way you describe. Whether it happens in 12 months or 72 is dependent on a number of things, including manufacturing flaws. And once one is run completely flat, it’s never truly reliable again. (I learned the hard way to replace the bastards the first time, not the fifth.)
If the new battery shows the slightest problem - dead, slow/hard starting, anything - within the next month, go back and insist on an electrical system check. Otherwise, chalk it up to random chance within the realm of normal lifespan.
I agree… your battery may have been unused, but indifferently maintained before you bought it.
If it’s a lead-acid battery, did you check the fluid levels before you put it in? It’s entirely possible that the battery’s water was low when you got it, and got even lower, and now you either don’t have enough for the battery to work, or the battery is sulfated as a result of the unbalanced conditions in the battery (acid too concentrated), and is permanently screwed up.
Take it back; almost anywhere will pro-rate the battery price, so you may end up paying something like 2/5 of the battery cost, and if it happens again in a relatively short period of time, you’ll know something’s up.
Very few batteries need water level checking, or even allow for it, any more. By the time you’re prying the caps off of a maintenance-free battery, it’s probably a goner for other reasons.
It sounds like the OP already got a pro-rate on the new battery. Unless it’s a total junk brand, they’re a lot more than $50 with installation. (And installation isn’t free on a lot of newer cars where brackets have to be removed, sometimes air boxes and wheels and other major components. It ain’t drag and drop like yer old station wagon.)
I was going to throw in my usual voltage check paragraph, but that always brings the grumpy expert out of hiding to correct my millivoltages.
I haven’t done this in years. All of my batteries recently have been sealed and you could not check/change the fluid level. That appears to be true of my car as the owner’s manual does not suggest checking fluid levels.
Has the car been in any accidents recently or hit something like a big pot hole? It’s possible that the battery suffered some internal damage causing such a quick failure rather than the normal, slow energy loss.
This is the original battery that came with the car, yes? So it may be quite a bit older than 20 months and, importantly, it may have been discharged for a long time while the car was in transit and sitting on the lot. The OE batteries are also sometimes of sort of questionable quality too.
Oddly enough, I’ve noticed that some Japanese cars that are actually made in Japan come with non-sealed batteries. They’re still maintenance-free since you shouldn’t have to periodically add fluid, but they have the level indicators and fill holes. I presume someone in the assembly process had to add the fluid.
And most standard aftermarket batteries are the same old lead-acid ones our great-grandfathers had in their cars. AGM and gel batteries are making inroads, but they’re far from ubiquitous and are usually marketed as premium products- usually as no-maintenance batteries or sealed batteries.
Questions
What month and year did you buy the car?
How many miles does it have now?
[Grumpy automotive instructor mode]
Did you, umm you know, actually READ your cite?
Eleven volts? You’re kidding, right?
Fully charged a 12V battery is 12.72V (12.6V and above is considered fully charged) this excludes any surface charge. More on this later.
12.4V is considered 75% charged
12.25V is considered 50% charged
12.0V is considered 25%
<12.0V is totally fucked
(Depending on the cite you read the above numbers may vary by 0.1V or so)
I submit to you that if measure the voltage on an inservice battery and it is much under 12.6V you have a fucking problem.
Either your battery is toast or you have a charging system issue and you will soon have a battery issue.
To remove surface charge so you can accurately measure terminal voltage either wait four hours or so after driving or if you just drove the car turn the key and headlights on for 30 seconds. Then key off and wait a minute or two and measure.
[/GAI mode]
Have you had your alternator checked? Is it possible you left the dome light on for several days?
Also, it might be a good idea to see whether there’s a current drain on the battery when the car is off. Disconnect one of the battery cables and put an ammeter between the cable and the battery. Be sure that all the lights are off and the doors are closed. The drain on the battery should be very low - lower than 50 milliamps.
Car is 20 months old with 9K miles. That’s 450 miles a month. That is very low mileage.
You could be in a situation where you just aren’t driving enough to keep the battery charged.
You may have to consider a battery maintainer.
I had a alternator go recently in a way that would not trigger the idiot light (as the switch for that is in the alternator). It did drain the battery which failed a few days before the 24 month replacement warrantee was up. But this battery did sit in a continuously discharged state for a few months before that (it wold turn over the car, but just barely - a friend was tending it while I was away and started it a few times but never let it run for long)
After the alternator failed I drove the car till lights came on. First the ABS light (I suspected a recently changed wheel speed sensor) , then the check engine light (now I was thinking something major may be going on). I put on the cabin light and saw it was very dim and suspected the issue. I shut off everything I could and drove to a place where I could charge up the battery. One by one new lights came on, the AWD system disengaged, Then one by one each system shut down and the lights went back off. Eventually the dash panel went out completely yet the car still ran. Soon after I could no longer accelerate beyond a very modest level, stepping the accelerator down seemed to bog it down. I did make it to a place where I could put a charger in it but it was way too late. After a full night of charging it made one brief but lame attempt of starting then would click.
To this day I am still impressed on how the systems shut down non critical systems one by one while still maintaining the ability to drive.
Possibly, but reread the OP. A completely dead battery two mornings running means either there’s a fairly strong drain (~1A or so) or the battery is faulty.
450 miles a month is 15 miles a day. While that’s low mileage by overall maintenance standards, and probably below most averages, it should be plenty to keep the battery charged.
I did read the OP.
Many modern alternator systems will NOT charge a dead battery. The are designed to keep a fully or nearly fully charged battery fully charged. There is a difference. I do not find it surprising at all the battery was low the second morning, and since no one tested the state of charge after that day’s driving you don’t know what the state of charge was, you are assuming it is fully charged. Also based on the average mileage the car drives there is an excellent chance it was not driven far enough to do much of a charge in any case.
Also just how the mileage is accumulated makes a difference.
Is it 15 one mile trips every day? Is it two 7.5 mile trips every day? Is there one 4,000 mile vacation in the mix?
Each of those is a different scenario electrically. That is why I said the OP may have to consider.
I did; my point was that if your voltage was somewhere between 11-13, it may be an issue of how charged the battery is, but that if it’s way off from 11, there’s something seriously wrong with the battery.
While he has the voltmeter/multimeter out, he may as well check the charging voltage - while idling, put the positive probe on the positive terminal, and the negative on ground (NOT the negative terminal) It should read 14 volts.
