I have a 2008 1LT coupe. I normally drive it every weekend, however, once I let it sit for about 3 weeks and the battery was dead, so dead I couldn't even jump start it (it wouldn't even try to turn over). I put a new battery in it, this was 3-4 months ago. Now once again I let it sit for 4 weeks (with a 4 month old battery that is beyond OEM specs) and once again the battery is dead. I am not leaving anything on in the car.

Is anyone else having these issues? I am afraid if I take it to the dealer they will mess around with it for a week or two and find nothing. I wanted to know if anyone else had this issue, found the cause and corrected it.

 

You can't let these things sit for 3 or 4 weeks with all the electronics.Get a battery tender for it and your issue will go away.There are very few people who let these sit that long that don't get dead batteries.Mine has been sitting for a couple of months on a tender with no issues at all.

 

Pretty much everyone with a C6 will have this issue. The OEM battery on average can go about 27 days on a charge without being driven. Some can go longer but without analyzing your driving habits for your weekend trips it is hard to predict. It can take nearly 30 minutes of driving to return the battery to a full charge just from having started it up with the radio and headlights on. You can theoretically end up with a dead battery driving every day for very short trips as you will use more than you will replace with each start up.

There are a lot of demands on the cars electrical systems even without any aftermarket electronics. If you are going to leave the car sit for that long you will need to get a battery tender, maintainer, priority start or keep buying new batteries.

 

As a average statement, no one should let a C-6 sit for more than 2 weeks without being started up and run to full temps and charge. You might get away with 3 weeks, but you are chancing it.

 

I have a 2008 C6 that I ordered new. Within three weeks, dead battery. It was a bad batch of "accessory computers" that Bowling Green got from their supplier. The drain was over 60mA and it should be below 12mA, if I remember correctly.
This was fixed easily via warranty. I kept the original battery. I have now had the car 13 months and drive it almost daily. No more battery issues, but I will probably buy a Optima soon, as we are in the AZ high desert and it is tough on batterys here.
I contacted the Bowling Green plant (I forgot the email address but I am sure someone on this forum has it), and stated my problem at the time.
To my surprise, I got a quick response (very nice email) and the tech dude said that (believe it or not) that I should probably get a battery tender if I leave it sit for more than a week at a time!
I do not have one, as I drive it often, but if GM says you should get a tender, perhaps we should thinkk about it!

Best of luck....these cars are pretty complex. I think I miss carbs, distributor caps, and the old stuff!

Desert Dog

 

Desertd. is correct; I contacted BG, too, after my 3 month old car/battery died after 21 days of non-use. BG recommended getting a battery maintainer, which I now have (and have never owned before), and use. It is on the car right now.

BG also said not to rely on "taking the car for a short spin, or letting it idle" to charge up the battery. It won't happen. The only way to get it really charged up is to go for a long drive, 30 minute minimum, at no less than about 1500 rpm.

It's a whole new world out there for our Corvettes and we just have to go with it---I don't always use my maintainer in the summer/spring, but I will put it on the car if I'm not going to use it for awhile.

Buy one; they're as little as $17, up to $80 or so. I just saw a Duracell one in Target for about $17. Walmart has the Schumacher for about $20, and all the parts stores have them, too, be it Battery Tender, Schumacher, etc.

 

I also have a 2008. Mine gets driven two or three times a week, but rarely long enough for a really good recharge after starting.

A good battery tender is you best investment. I use mine weekly. This is just my opinion, but I think you would be better severed with using a battery tender to maintain your battery rather than shelling out a lot more money for supposedly miracle battery.

 

It's an academic question but I'd like to know why some cars can sit without use for 2 or 3 times longer and start up. Mine as sat without using my battery tender for almost 6 weeks yet it started right up! What the hell is the electrical difference between identical C6's? It seems there MUST be some electrical issues that GM has never fully identified. BTW.. mine has every option except OnStar and NPP exhaust. It's a mystery to me what the REAL difference is between cars........ BTW.. mine still has the stock battery from 06!

 

You are NOT alone. This is a known issue on the C6. I did a search, and...there are over SIX HUNDRED threads (336+301+24) with "DBS", "dead battery", or “battery problem” in the title in the C6 section.

To prevent a dead battery in the future, you could get a PriorityStart. (www.PriorityStart.com) It's a small device that you wire-in near your battery. It monitors battery voltage and automatically disconnects the battery when it drops to 11.7 volts. It essentially is an automatic battery disconnect switch. A trickle charger is another way to go. However, if you forget to attach it...DBS.

Some C6s have a problem with how they handle the electrical circuitry during shutdown. The firmware in the BCM (Body Control Module) has a flaw that creates a "draw-down" (current leak) on the battery that results in a dead battery. There is a BCM "flash" that is available through the dealer or a good corvette shop that will eliminate this battery draw-down. Your local Chevy dealer should have a TSB (Technical Service Bulletin) on this issue. If your car is still under warranty, the BCM flash should be free.

My C6 used to go dead in one week. A Corvette shop in Dallas reflashed my BCM, and the problem went away. The BCM flash (if needed) will make the battery charge last longer…but…you will not be immune from DBS without either: 1. driving the car regularly, 2. a battery charger attached, or 3. a battery disconnect.

Good luck.

 

While your information is correct it would be important to note the the unexplained draw down which came to be known as DBS, was common to 2005 cars and affected only a handlful of 2006 cars. It was also most noteably on maual transmission cars. The BCM flash is specific to this issue, newer cars have it all ready.

While DBS results in a dead battery, a dead battery is most certainly not always DBS. DBS by the definition was the car that could be shutdown properly, left with no electronics (oem or aftermarket) on and with a fully charged battery and it would be found dead in 48 hours. Letting a battery fully discharge over a period of weeks does not meet the criteria for DBS.

 

I'll stay out of this one Haven't visited here in a while.

 

The owner's manual says: "If the vehicle is driven infrequently, remove the black, negative (-) cable from the battery. This helps keep the battery from running down."

"For extended storage of the vehicle, remove the black, negative (-) cable from the battery or use a battery trickle charger. This helps maintain the charge of the battery over an extended period of time."

My C6 is garaged, so it's easy to hook-up a battery tender (NOT a battery charger!). I also believe a good battery tender (like the CTEK 3300) will extend battery life. Of course, using a battery tender is difficult if you park outside away from an electrical outlet.

Does anyone know of a quick-disconnect for the negative terminal? Seems like that ought to be cheap insurance for infrequent use when a battery tender is not practical.

Of course, you'll have to re-index your windows if you disconnect the battery. But I think that's pretty easy.

 

I geuss I am the lucky one! I have an 08 that sits 4-5 weeks at a time and never a problem! Go figure!

 

If it going to sit for more than 2 weeks use a Battery Tender and you will have no issues.

 

I put a charger on mine every two weeks for a couple of hours since it's in winter storage. It gives me an excuse to take the cover off and admire the car, as well. I have a digital voltmeter whixh reads a battery voltage of 11.98 volts before I hook up the charger.

 

That makes me start to wonder, too, Craig. Mine HAS onstar and NPP. And while I don't have either of the remote controllers from vendors, maybe something is going on with one or both of these two options.

Otherwise, I have no explanation whatsoever for why one Corvette can sit for 6 weeks plus with no starting issues, and mine goes to the Big Kaplooey in 3 weeks. I just don't know.

 

Just buy a battery float charger from Harbor Freight.. List $9.95, on sale often for $6.

My 3 Vettes each have their own.... I really splurge.....

 

An acceptable parasitic drain is about 10 milliamps. It should be checked after the vehicle sit for at least 40 minutes. It's recommended that the negative side of the battery be used to check the amp drain. (never could understand why)

 

The OE auto manufacturers have a 45 stand test the battery has to meet. The theory is great, but look at all the issues that have shown up since 2005 and kill the batteries.

The ACDelco battery that comes in the car is as good as any OE battery and has to pass tests that aftermarket batteries don't, but it is the "unknown" issues that are the real problem.

I have an Optima Yellow Top with a battery tender, but have left my car for over a month without starting and without the tender and it still starts. It's not that I changed the battery to an Optima (yellow car, yellow battery), it is because in 2006, the issues were with auto trans cars (that a reflash fixed) and I have a manual.

Until April of this year I sold car batteries to the car companies and had a team of battery engineers that worked for me. The guy that called on BG sat right outside my office, so I do have clue.

 

Don't you think a lot of the battery issues start when the car is at the factory/dealer and not being started or driven. Once a battery is killed completely is is never ever right again. When I bought my new Corvettes I had the batteries changed to a SEARS Diehard Platinum to keep this dead battery syndrome from happening. They are guaranteed to hold a charge in the car for 2 years. No battery tender for me to burn my house down.