Battery gone dead?

[jcs44]

I was going to drive her to work this morning, but when I opened the door and no lights came on, I said oh sxxt. I tried the key and not even a click. The battery is over 3 yrs old and the last time I drove it (last week), I thought the voltage was running a little high - like 14.7-14.9V. And this after I had on the charger overnight. Thoughts?? :confused

Thanks,
JCS44
96 LT4 Vert, triple black

 

[B17Crew]

I can’t help but wonder if the batteries charge had gone so far down that a overnight charge would not bring it back from a low level state.

At three years and the C4’s constant draw on the battery, it sounds like a possibility.

Good luck and please keep us posted as to what you find!

B17Crew

 

[jcs44]

Well, I had it on a float charger that turns off when the battery is charged. I did notice that it took longer than in the past.

JCS44

 

[B17Crew]

Hmmmmm...

I had a similar thing happen to me with my original battery.

Although my battery was about 5 years old. I left my Battery Tender off for a week though. I went to turn her over and I got nothing, not even my courtesy lights were illuminated.

One of the C4 guru’s will chime in here soon to lend a hand.

B17Crew

 

[354RwHpLT4CE]

battery

14.7 volts after charging is ok.Just curious,are you sure the alarm didn't go off?I have had that happen to me before,Came out after work and she was non-responsive.After removing key,and shutting the door....clunk,the doors locked and the dome light came on. fired right up.Alarm just needed to reset with the key fob present.Wife also likes to leave the dome light on,that will suck it down.Just ideas.Let us know.

 

[Stallion]

...and the C4’s constant draw on the battery, it sounds like a possibility.

What draws current when the car is off on our C4s?? I'm guessing some function of memory for the ECM, but what else? That shouldn't be drawing much at all, no?

 

[B17Crew]

What draws current when the car is off on our C4s?? I'm guessing some function of memory for the ECM, but what else? That shouldn't be drawing much at all, no?

The factory alarm is a constant draw on the C4.

B17Crew

 

[jcs44]

OK, got it fixed. That battery was stone cold dead and would not register anything on a volt meter. So I guess it was shorted or open internally. Anyway, new battery solved the problem quickly and all is normal. One question though: What should the volt meter be reading when all is normal?

Thanks, JCS44

 

[6speeder]

:...... What should the volt meter be reading when all is normal?..............

In theory, a 12V battery will register 13.2V static when fully charged (2.2V per cell).

Normally, a battery will register 12.0+ static, and 14.0+ dynamic (depending on accessories in operation).

At start-up, 14.7 is normal, even with a fully charged battery. After a few minutes, the reading should return to 14.0+.