80atez

I have a situation I want to see what y'all think.

I have a '08 z06 and replaced the battery after 8 years just because last year. It's never had a battery issue. So 1 yr into the new one, I went to the store with my son and got distracted and when I was about to turn her off, I popped the clutch and stalled her. Didn't think much of it, done it before, no big deal... Got out, went to shop. Tried to lock her with the fob but she didn't honk at me so I figured she was upset. But as I had nothing inside to steal, just went inside. Was there for over an hour. It was hot outside.

So I come out and she's dead.

got a jump, charged the battery once home - not very discharged... Hum??
On the way home, volts only in the mid 13's. Usually 14-14.5

Had it load tested. It's fine.

Drove it twice since, seems fine.

My theory is I actually left it ON for over an hour and it was hot so it was running the radiator fan and what not. That is, I stalled it with the clutch drop, so it never really shut off. So after an hour of sitting and maybe running the cooling fan, the battery was down.

Does this make sense? And if so, please beware of this if you read this and get my jist.

So next time I do a silly thing like drop the clutch before turning her off, I'll maybe restart and then shut down correctly.

Gary '09 C6

check the ground cable at the starter...there have been several CF reports of the same corroding (from heat) at the starter terminal,
which could cause intermittent starting...and time to have the alternator tested as well.

80atez

I assume the ground is the one with the exposed fine copper threads visible? That and the other cable (pos term?) both look like new and are tight. Thanks.

So you don't buy my theory that it was "left on"?

Gary '09 C6

it's certainly possible, but I just don't know...if the battery was only slightly discharged the starter should have been working, even at a slower speed ?

Dan_the_C5_Man

The BCM has algorithms to protect the battery against the scenario you described, so no, I would not assume the issue was you walking away from the car and it "stayed on".

ratomicZ06

Ive left the accessory on befote and it drained the battery. I found out the hard way that if you turn acc on, to roll down windows for example, the quickly try to turn acc back off.... it wont. You have to wait for gauges to go through all their sweeps, etc, before you can actually turn acc off.

Anyone else agree?

ratomicZ06

Ive left the accessory on before and it drained the battery. I found out the hard way that if you turn acc on, to roll down windows for example, the quickly try to turn acc back off.... it wont. You have to wait for gauges to go through all their sweeps, etc, before you can actually turn acc off. The acc will STAY on draining battery.

Anyone else agree?

rjacobs

In your case(OP that is), unless you pushed the off button after stalling, the car was still 100% on(ignition on mode), just the engine wasnt running. I believe in "ignition on" mode that the battery protection that is present(should be present) in "accessory on" mode, isnt present. I bet while you were gone the car was flashing "fob not detected" or something like that as you walked far enough away. However the car wont shut itself off(as you found out). Same as if you let the car idle and walked far enough away that your key was out of range.

You can force the car into "ignition on" mode for holding the start button down for 10 seconds without the clutch(or is it hold accessory down for 10 seconds). This is also the mode you need to get into if you ever need to "pop start" the car.

CrystalRedZ07

Went shopping at Lowe's and before I got out of the car I turned the ignition on to crack a window open and forgot to turn it back off. When I came back to the car an hour later, I had this message:


BATTERY SAVER ACTIVE
This message displays when the vehicle has detected that the battery voltage is dropping beyond a reasonable point. The battery saver
system starts reducing certain features of the vehicle that you may be able to notice. At the point that features are disabled, this message
is displayed. It means that the vehicle is trying to save the charge in the battery. Turn off unnecessary
accessories to allow the battery to recharge.

Everything started back up fine, but I learned a lesson!

Javvy

Im with ratomicZ06, I turned the acc on at a show on Sunday and left it on.
Car was so flat it wouldn't turn over but I could hear it clicking and trying.
Got the guys to push start me, it kicked off straight away, no probs since.

ratomicZ06

Hmmmm.... never saw that message. Wonder if diff years the programming was different? Im an 07.

Also.... i find it "difficult" to get the ign mode off. Even if i wait until it gets thru the boot up sequence i have to press the start button down multiple times to get it totally shut down.

I find myself doing this alot bc i want the windows up or down so i need to turn ign on in order to do that, iow......just reaching in the car, hit the ign button up, roll up/down windows, wait for boot up cycle (takes 10 - 15 seconds), turn ign off.
It doesnt always turn off!

Ever since i killed battery that one time im real careful now. (I also changed all the bulbs to leds).

Dan_the_C5_Man

Well, I won't profess to have tested every single scenario, so I can't challenge your assertions. And to your point, it is possible GM may have refined the code over the years (I have an '11).

dmuellenberg

Try this next time - press the lower part of the Start button and it should go into ACC mode (amber light on), hit the Start button again and it should go into RAP mode (red light on). Roll down/up your windows and then open the door. Everything should then shut down without having to hit the Start button to shut down.

ratomicZ06

I will, thanks. Pain inthe *** way ive been doing it.

80atez

Totally old thread, but I thank everyone who posted. I sort of forgot I started it..

The battery I had was new, and since that event in the spring, it is working fine. No issues at all.

So I assume the above posts were correct that stated that I had not shut the car down and it sat "on" for an hour in the heat. That was enough to drain it down, I suppose.

Too-Fast

Thanks for resurrecting it, I learned something.

C5 Hardtop

Wrong time of the month..too hot outside and leaving her alone for an hour after shutting her down like that. Yes, do fire her back up and give her some juice after killin' it.