Z06Vette.com - Corvette Z06 Forum

**jub jub** · 08-28-2008, 02:11 PM

I've noticed that if I don't park the Z with it in reverse, the battery goes dead in a couple of days.

I was told on another forum that there is a PCM update that will take care of the problem but I will loose my tune. I can always flash the PCM with my current tune but then I wonder if I'll overwrite the update for reverse.

Anyone know if this is the case?

dmuellenberg · 08-28-2008, 03:57 PM

Quote:

Originally Posted by jub jub

I've noticed that if I don't park the Z with it in reverse, the battery goes dead in a couple of days.

I was told on another forum that there is a PCM update that will take care of the problem but I will loose my tune. I can always flash the PCM with my current tune but then I wonder if I'll overwrite the update for reverse.

Anyone know if this is the case?

Don't know about the tune, and I'm not sure which one of your cars you are referring to, but if you are referring to your 2007, then something else is causing your battery to drain because that issue was fixed with the C6.

**PerforminNorman** · 08-28-2008, 04:03 PM

That was a glitch known in the 05s but not the 06s and up. I think you have something else going on.

maxib · 08-28-2008, 05:01 PM

The easy answer to the problem is park in reverse! That's what I do.

briann510 · 08-28-2008, 05:29 PM

Not sure if its only C6's the if not in reverse battery goes dead affects but I've never parked in reverse in my 03. Its always 1st.

pauln64 · 08-28-2008, 05:59 PM

I don't have any problems with mine. You may want to check if you have the "zero" drain hook for for the mild to wild switch. That's what I did with mine. Sent ya a PM since I can't post the website here.

**wvphoto** · 08-29-2008, 06:06 AM

i had a saab many years ago.. you couldn't take the key out unless you were in reverse..

that trained you to always park that way.. and you knew what gear you were in when you started the car..

Top Cog · 08-29-2008, 10:37 AM

Hey jub,
My guess is the previous owner had a few deep discharges and now you have limited charge-holding capability. I suggest a new battery and a Battery Tender. Mine didn't sit much for first 6 months but first time it sat for 3 weeks I barely had enough jiuce to start. Bought my tender and plug it in anytime it'll be down for 2 weeks or more. After 26 months and 14,000 miles absolutely no issues or problems. If you get a tender, do yourself a favor and order the cigarette plug adapter too...really makes it convenient to use. Good luck and enjoy that beast.

**dsinned** · 08-29-2008, 10:24 PM

Here's something to add regarding a Battery Tender . . .

I just put my 08Z on a Tender this morning after the car sat in the garage for a couple of days. Of course, as expected, the Tender's red LED came ON indicating it is charging the battery. Almost 10 hours later the red LED was still ON. I'm going to check again tomorrow morning (24hrs later) and see if that red LED is still ON. It shouldn't take any longer than that to recharge a healthy battery.

I also took a voltage reading at the fuse box under the hood where the positive side of the battery connects to and it read 12.54VDC. That's about right for a battery under a maintenance (float) charge. Yet, the Tender's charging mode is still active. I don't what to make of that (yet).

Maybe the C6 has more "sleep mode" drain current on the battery than earlier generations. The Battery Tender will automatically switch to an active charging mode when there is maybe 100mA or more of load on it. If a parked C6 is draining its battery with that much "sleep mode" load current on it, it is conceivable an otherwise healthy battery will be dead in less than a few weeks time. But, if that were true, Chevy would have a lot of pissed off customer so I doubt that is an issue with these cars.

Tony Skarbic · 08-30-2008, 06:37 AM

The Battery Tender is designed to maintain a fully charged battery. It does not function as a battery charger.

**jub jub** · 08-30-2008, 06:57 AM

I haven't been having the problem as of late and I've checked the drain current with the car in 1st. No more than .03 amps or 30 milliamps which I beleive is acceptable.

So I don't know, maybe I left something on.

I agree though, a battery tender is a good idea for this car.

**dsinned** · 08-30-2008, 11:35 AM

Yes, right you are but they do actually have a charging mode of operation too. My Battery Tender is capable of "trckle" charging at 1.25A. (There's a smaller, AC wall socket plug-in model that can only output 750mA of charging current.) I realize that's not very much, but it still qualifies as a (trickle) battery charger. Unlike a heavy duty charger, with a much higher charging rate - maybe as much as a 100A, a Battery Tender will never be harmful to a car battery even if it is "charging" or maintaining it for a long period of time. I have a working knowledge of how this product works. After a generally short initial charging period (in most cases you are correct in assuming the battery is already fully charged, so this period is sometimes extremely short) the battery terminal voltage returns to nominal (about 12.5V), and the Unitrode Controller IC inside the Tender automatically switches to a "float" or maintenance mode. The LED should turn (and remain) green almost continuously at this point. However, if you unlock the car while it is in this mode, it will immediately switch back to charging mode until the battery's nominal terminal voltage is restored.

I agree. A Battery Tender is cheap insurance while garaging any vehicle. I generally use them on motorcycles but they work just as well on any so-called "maintence" free car battery.

Dev · 08-30-2008, 12:40 PM

Quote:

Originally Posted by dsinned

Here's something to add regarding a Battery Tender . . .

I just put my 08Z on a Tender this morning after the car sat in the garage for a couple of days. Of course, as expected, the Tender's red LED came ON indicating it is charging the battery. Almost 10 hours later the red LED was still ON. I'm going to check again tomorrow morning (24hrs later) and see if that red LED is still ON. It shouldn't take any longer than that to recharge a healthy battery.

I also took a voltage reading at the fuse box under the hood where the positive side of the battery connects to and it read 12.54VDC. That's about right for a battery under a maintenance (float) charge. Yet, the Tender's charging mode is still active. I don't what to make of that (yet).

It might help to take the battery off the car and put an initial charge on it. That way you don't have the car draining it while you're trying to charge it.

**dsinned** · 08-30-2008, 08:00 PM

That's not the point I'm trying to make . . . if the Tender will not come out of charging mode, that means there is a relatively "high" drain current load on the battery. If so, this could explain why some owners are reporting that they are having problems with dead batteries (w/o a Tender) after only a few weeks in storage.

***UPDATE***
Since I put the Tender on mine, it eventually did go in to float charge mode (green LED), so like someone posted earlier, the Z06's sleep mode drain current on the battery must be fairly insignificant, and I don't think it has anything to do with what gear you're parked in.

Dev · 08-30-2008, 08:16 PM

Quote:

Originally Posted by dsinned

That's not the point I'm trying to make . . . if the Tender will not come out of charging mode, that means there is a relatively "high" drain current load on the battery. If so, this could explain why some owners are reporting that they are having problems with dead batteries (w/o a Tender) after only a few weeks in storage.

I realize that wasn't the point. I only suggested it to help get the battery charged and maybe help diagnose the problem....