Twice, in the past three months I've had my battery go dead after sitting in the garage for five or six days without running (bad weather). I had the battery and alternator checked and they're OK. The car is an 09 3lt.
Is there some electronic thing not turning off? Or what?
Any help would be greatly appreciated. Wally

 

These cars need a battery tender, buy one and use it often when not driving the car.

 

Most likely you have something not turning off. If you have a multi-meter, wait 20 minutes or so after you shut off the car. This will assure all the auto shut off components are off.
The reading in milliamps should be no higher than 7-14 Ma.
If it's higher than that, then you have a parasitic draw that you have to find.
Some of the common areas are:
1) 2005 Manual transmission, you must leave the transmission in Reverse when you shut it down, or it will drain the battery. This does not pertain to 2006-2013 vehicles
2) OnStar Module has been known to get a glitch and start drawing current even with the car off. If you suspect the VCIM (onstar module) then unplug all the connectors but the one in the pic, and the parasitic draw will go away.



3) Do you leave I-pod or such plugged in to your accessory plugs? Even if the IPOD devise has been unplugged, this device must be removed from the vehicle completely. The devise triggers the Bus to maintain power even when the devise is not powered.

4) Pull the fuse for Courtesy lamps. One of the culprits is the under hood lamp, if your car has one. Unplug the connector (right side of radiator)

5) 2005-2013. Are the headlamp or day time running lamps lit? With the key off there should not be any lamps lit. Perhaps the headlamp switch has been inadvertently turned on. Remember the only time the headlamps are turned off are in the off position or automatic. If the customer has turned the stalk to parking lamps or headlamps the headlamps will be lit when the ignition is off. There should be a chime to remind the driver the lamps are lit but often times the chime is ignored. These are on the 20 minute battery saver circuits but it does not take many short start and stop trips to draw the battery down to a voltage that will not allow the car to start 2005-2013.

6) 2005-2013. Is the radio still on? There have been reported cases where the radio stays powered up after the vehicle is shut down. This has been an intermittent complaint and it only occurs on cars equipped with the Bose systems which is the multi-disc player and the Nav radio. Only service the radio if this concern can be identified. 2005-2013.

7) 2005-2013. Close both doors. After 2 minutes are there any interior lamps on? Visually check the map lamps on the rear view mirror and vanity lamps. Often these lamps can be bumped and if the car is only driven during the day it will not be noticed. Under dash lamps are controlled by the courtesy lamp switch. Many customers do not realize that the switch has been bumped and they have been turned on. The old switch (C5 cars) used to push in and you could tell it was off. The new switch (C6 cars) does not press in. It can be bumped and turned on and go unnoticed. There should not be any lamps on in the interior of the car after 3 minutes if the ignition has not been turned on, including the cluster. Note anything that is on.

This should give you a starting point on what to check.

Good Luck, and report back if you find the culprit.
And...a battery tender is a must if the car sits for long periods of time. That will assure that when you go to start it, it will.

 

keep it on a tender if it sits for more then a couple days.

 

Lead Acid batteries do not like to go below End Point Voltage, 20 volts for a 24 volt battery and 10 volts for a 12 volt battery. Corvettes have a 12 volt battery. If your battery has gone 'dead' (starter will not engage just the chatter from the start relay) twice in three months then it has gone well below the End Point Voltage threshold and most likely has no capacitance and is no longer good. It should be replaced very soon.

 

Thanks for the quick responses, I now have a Battery Tender on order and I will try to find the culprit - I'll reply if and when I find the problem.
Wally

 

Car should start after only 5 days. After two weeks is a different story.

 

hmmmn maybe I'm just lucky, but I can park my 2013 427 Convertible for longer than 2 weeks without hooking up battery tender and it will still start, and it's now over 3 years old(built MAY '12, and purchased July '12).....in addition, I ran the battery down accidently (left ignition / radio on) during 2013 Vettes 4 Vets road trip to Talladega, and had to get jump start, and I know that's not good for the battery, but I'm still using the OEM battery. Now during winter storage, I do have it hooked up to my CTEK battery tender.

 

Battery tender is the way to go! If you live in the colder areas, than most certainly always put the trickle charge on it when its cold out or if it's going to be parked for more than a week!

 

I have had the same experience with the original battery on my 2010 coupe. Have NEVER used a tender. On my last visit to the dealer, had the battery checked and it was still good; but, I plan on getting a new battery this spring. Guess I've been lucky, too.....