[ds968]

I drove  the car on Friday to work , it sat there 6 hours or so, then drove it to a grocery store , stopped for ten minutes there , and then drove it home and parked it in the garage. Started immediately on all three  occasions, drove perfectly fine all along. 

I had to get something out of the garage this morning, which required me to move the car.  I tried to start it but it was dead .  And when I say dead, I mean dead !  No lights at all, no sound , nothing !!  I put a voltmeter on the battery and it shows 7.8 to 8.8 V !!  I have never seen such a low voltage in my entire life . I can’t test the charging system becauseI can’t turn the engine on to see if the alternator is charging .    So I put it on a battery charger and will see what happens tomorrow morning .  The battery is less than two years old , and it’s an Interstate, so top shelf , I have  them in all my cars , and not a single one lasted  less than eight years.  

What it the world can drain a battery that much and that fast ?   I don’t have any lights  switches left on ( headlights, or fog  lights , or parking lights ) , there is no glove compartment light ( I turned that off years ago ) , there is no hood light ( disconnected that also many years ago ) , and the same with the trunk lid light .  So what the hell is happening here ?!   Anyone have some ideas ?  

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[Inkedupfatboy]

Interstate batteries are not what they once were - I never use them anymore. I haven't bought an interstate in nearly 20 years.

Down here in FL if you get 4 years out of a battery you are doing great. The heat kills them.

If you are not running a battery tender, is the clock running? What about the under hood light if that came on for some reason? Mine is d/c'd as I leave the hood cracked for the battery tender. 

I have to keep one on the car and bike as I drive them so infrequently.

Good luck..Hope you get it figured out..

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[Rap]

I had my 911 go dead on a battery tender. Got it jumped, ran it for 15 minutes and turned it off. Dead. Put it back on a  bt and two days later the tender shows green . I will get a ner battery this spring. Drove my truck to Loews. Shopped came out and the battery was dead. Got a jump and immediately took it to the shop for a new battery. Original on a 2018. The 911’s has been on the car since 2018 when I bought it. Older than that. This year all battery’s get replaced.

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[ds968]

I put it on a tender overnight to see if it charges at all .  I disconnected the cables .  I’ll check it this morning .   If it shows a decent amount of voltage I’ll reconnect the cables and check it the next day to determine if and how much of a parasitic draw there is .   But this was not a slow drain, this happened suddenly , almost as if a short occurred and killed the battery .   Either way I’ll probably buy a new battery ( unless there is a major draw , in which case I’ll take it to the shop to have them troubleshoot the system to see where problem is ) . 

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[ds968]

After the overnight trickle charge , this morning the battery has 12.41 V.   I put the cables back, fired it up and used a load tester voltmeter .  Charging system is at 13.5 V, so at least the good news is that the alternator is ok.   Then I turned on the headlights, fog lights , radio,  and AC .   Under load the charge shows 13.3-13.4 fluctuating .  The battery remains at 12.4 after I turned off the engine.   So I’ll leave it as is now for a couple of days and then check to see if the battery dies again.   Either way I think a new battery will be needed.  

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[Rap]

Why not leave it on the tender until you take it for a new battery?

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[ds968]

Why not leave it on the tender until you take it for a new battery?

There is no rush, I want to run a couple more tests to eliminate what may be a major parasitic draw before I ruin a brand new battery .   Besides,  I’ll likely just remove this battery and take it in for a core return refund ( I’ll drive the SUV to the shop with it ) and buy the other one to bring back.   I don’t want to take the chance of driving the 968 and the battery dies in route , leaving me stranded and having to call a tow truck ..

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[ds968]

This makes ZERO sense ( to me anyway ..).  <b>Load tested </b>: 95% health / CCA level . WTH, just a couple of days ago , this battery was dead and buried with around 8 volts ( +/- ) on it . And it sat for the last 24 hrs , without any trickle charger on it .

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[94SilverCab]

Have you replaced the wiring harness on that car? Mine was starting to have gremlins before it was changed.

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[ds968]

Have you replaced the wiring harness on that car? Mine was starting to have gremlins before it was changed.

Yes, the wiring harness was replaced.   But it’s been many years … and although the car is always garaged, without any vermin to get to it, I understand the heat of the engine can eventually affect the wires to their detriment .. but I drive rarely, so that should not be an issue .  

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[ds968]

So the shop tested the battery with their Bosch tester. Prefect readings, under load . They asked me if I can leave the car with them for two days so they can test if there‘s any parasitic draw . Two days later , the battery was at 99.7 % where it was when I brought it in. Resting is at 12.71 V . Charging is at 13.8-13.9 . It’s a 600 CCA battery, and it tested above that , at 642 ( again, two days without driving or a trickle charger on it ) They said they’ve never seen even a brand new better test above the CCA capacity . They have no clue why it drained as it did when I experienced that event.  I’m losing confidence in these guys .. 

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[ds968]

Well, from now on I’ll just keep a trickle charger on it when the car sits in the garage for more than a couple of days .  Can’t hurt . 

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[Inkedupfatboy]

Stop using it to power the flux generator and you will be fine.  


Or..maybe some homeless guy is charging his phone off of it...

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[ds968]

Stop using it to power the flux generator and you will be fine.  

Or..maybe some homeless guy is charging his phone off of it...

    :lol:  :lol:

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