ok, I'm kind of giving up.
2005 MN6. Ran well for 1-1/2 years, then repeated dead battery syndrome. Here are some details.

1. ECM flash done at dealer 3 months ago.
2. because it had been totally discharged several times, threw out stock battery
3. replaced with Optima Yellow top D34/78
4. installed Priority Start module.
5. yes, this is the model that requires transmission to be left in "R" or else battery drain. But I check religiously each time the car is stopped.

Battery demands:

1. window valet installed.
2. otherwise totally stock
3. daily drive - only 1.2 miles each way to work and back, so no real time to recharge during normal driving.
4. Often ride motorcycle, so car can sit for 2 or 3 days at a time without being started.

So, after the dealer telling me that they can find no problem, then me getting new battery, priority start -- and now a few months later dead battery (again).

If there were a battery drain, shouldn't Priority Start have detected it and cut off the battery connection?

the big question: should I just expect that my demands on the battery are too great (sits for days, then taken for very short drives), and just accept that I have to put a "battery tender" on her each night in the garage?


Does anyone think there is an good to come from repeated trips to the dealer? I'm there about every 3 weeks with some problem or another.

Well, wanted to post a note to see if any of you who have garage queens (rarely driven and then for short drives) find you have to use a battery tender all the time? Sure didn't have this trouble with my 10-year old Mitsubishi with the same demands placed on her. Thanks for any opinions you guys can offer.

 

I think you should go with the top of the line Delco Profession series battery and that you are the perfect candidate for a battery tender.

 

Bugman, I have used many suggestions on your site...thanks...

Priority Start SHOULD have shut down the battery drain at the preset voltage. I just read it recently but have forgotten....Anyway, sounds like some other situation, though I agree with the poster above that 1.2 miles each way probably won't keep the battery charged....again though, Priority Start should have shut down the loss. It works for me.


anothercrisis

 

Remember.... Just because a battery is new doesn't mean it can't be bad. I had 3 bad Die hards in a row a few years back. A bad battery can lead to a lot of unnecessary and frustrating trouble shooting.

 

You might not be recharging the battery full enough each time you drive it, if your only driving 1 1/2 miles. When starting a car you are discharging the battery quite a lot, and this depends on the time of year, temperature, and other factors. But after the car is started then the alternator must replace that same amount of energy that was removed from your battery when you started the car. If your headlamp are on along with other electrical devices then it will take longer to recharge your battery. Maybe your 1 1/2 mile drive is just not long enough to do the job of recharging the battery. If the battery is not fully charged then after every restart it depletes your battery a little every time until the car wouldn't start. I'm assuming (cause I don't know) that the start sequence goes thru the computer. Depending on the computers design there is a threshold where the computer will not respond due to the fact that the battery voltage is to low. I don't know what that value is but your battery might not be dead but low enough to disable the computer start circuit. It sounds like you need a battery tender. I use them on my car and motorcycle and have no problems with batteries. Good luck, let us know how you make our.

 

i suspect it's simply due to the 'short commute', maybe every other day take the 'long way' (add 15-20 minutes to the drive) home.

is the 'priority start' tripped each time?

i too have a very short commmute, by the third day my 'running' volts will dip down into the 12's. when that happens, i just take a short cruise to get a 'recharge' in.

 

If the flash didn't help, I don't think repeated trips to the dealer will do anything other than aggravate both of you. And your site has helped me as well.

 

I guess you could consider my 05 mn6 coupe a "semi-garage queen" with only about 9k miles since 8/04. I drive it to work 2-3 times a week (20 miles total), seldom on weekends, and have garage stored (never <40 deg) from late Dec to late Apr the last 3 years on a tender. I'm in the mode of hooking up the tender if it's to sit longer than 2-3 days. I religously follow the required shutdown procedure and always leave it in reverse at the end. I never return to nuetral as others seem to do. I used to always leave my manual cars in first gear anyway, so this is not an issue with me. No DBS to date and we'll see if the battery can last until this fall.

One thing is strange though. I use another tender to keep two 12 volt Marine batteries (each 2 years old) charged over winter and during the week for my boat. I rotate the tender between each about once a week. When switching to the next battery, both the red and green light will blink for about 1/2 hour before turning solid green only. With the C6 it's different. If I immediately hook up the tender to it after driving 10 miles home from work, the red light only comes on. About 1/2hour later both red and green lights are on. Then after about another hour it will finally turn to solid green only. Weak battery or C6 charging rate not enough? Voltage guage does indicate >13.5 while on the road. Comments welcome

 

It sounds like the dealership did everything. The question is: did they?

When you say they checked everything, I assume they came back to you and told you there were no shorts in the system, no drains other than the usual and that the complete charging system including the alternator, was working within specs, correct?

I don't know this for a fact but if what they did was check for codes, reflash and say all done, that may not be enough. You should know, is there a better dealership with more knowledge and ability, or have you already gone that route? What does the regional warranty rep say about your car, if you've called him/her in?

I wouldn't mention the distance of your commute when talking with them. Granted, it's short but I still think that's not the issue.

 

bugman, is there an "Auto Electric Shop" in your area, you need to have the battery, alternator and the entire electrical system checked for any drains, not just with a test light but with a digital VOM and someone who knows how to use them. This should not be happening, the Corvette is no different than your 10 year old car, just a few more electrical devices. My 05 will sit for weeks and is somtimes driven on very short trips, never a problem. I think part of your problem is that GM's warranty's pay program does not benefit the technician in more complex problems and sometimes we always "think" it's a computer issue when you need to check the basics first. I just had a similar problem that a small animal ate the wiring on a car that was sitting for only 3 hours in the driveway.

 

I have left my 05 in the garage without starting for as long as 8 weeks during the winter, and the battery has never let me down. It's weird how some cars have all these problems, then others are perfectly fine.

 

I JUST THROW ON THE BATTERY TENDER WHEN IT'S PARKED for more than a day or two just to be on the safe side.I have heard of bad OPTIMA batteries too,so check that out.

 

Bugman I have the same scenario as you. I have had my car in 3 times in the past year for DBS. My dealership has done all the necessary flashes, etc... they have tested the battery, etc... the latest GM bulletin on DBS flashes is two+ pages long and is a checklist for the dealership on what to look out for. In my case, I have it because I do not drive the car enough. With Chicago winters it only adds to the problem. I keep mine on a battery tender when I am not driving it. I don't like hooking it up and unhooking it, but that is a small sacrifice compared to going out there and having no battery power at all. If it makes you feel any better I was at a exotic car dealer over the weekend where they sell Vets, Vipers, etc.... the guy with the wheeled battery charger was very busy jump starting cars. Good luck to you

 

Have you actually tested the Priority Start to see that its working? I tested mine and it does as advertised. Pushed the cig lighter then started car.

 

If you go the battery tender route (and I would have the entire electrical system checked by a competent shop first, as suggested by slow ride) you may want to use the aux power plug in the console as the entry point. I have been using that for several years now and it makes the hook up a snap.

 

I have a '07 that 3 times the battery died in my garage. The second time it died I put in a Priortity Start (tested successfully) and Battery Minder Tender. Just recently (with the car sitting for the last 2 months with the tender running) it died again and the Priority Start FAILED. I think that Priority Start is a drain on the battery so I wound up getting myself a Optima Yellow Top D35 from AutoZone (and got $8.00 credit for my 8 month old Delco battery core return!). I skipped putting the PS in this time and put jumper cables in the trunk. At least the Yellow Top can be recharged 100+ times and whenever my car sits for more than a few days I will still be using the Battery Minder tender which also de-sulphates the battery.

Bugman...your Yellow Top Deep Cycle can be recharged 100+ times without any problems. I would remove the PS and get yourself a Batttery Minder Tender. http://www.batterymart.com/p-battery...y-charger.html

 

I work for a battery manufatuerer and my engineers would agree with what he says. You are stepping the battery down by not driving enough.

 

That is the exact tender that I use.

 

Sort have just been through simlar but I do drive mine. 05 MN6 that I had 1 DBS about 6 months in and put in Priority Start. For the next 18 months priority has "saved" me about 4 times (including letting car sit outside in Winter for more than a month. Last week -dead and priority start didn't give it enough to start the car. I jump started - ran 20 miles - shut it off and next morning dead.
Took it to dealer (after removing PS since I didn't want it blamed) - they said battery had dead cell, replaced it and did a couple of software upgrades. Before the upgrades the said drain after shutting off was about 100 milliamps - after upgrade 17. Not that I totally believe all that I'm told but I think after 2 years the battery just finally died.
I'm going to run for a while without priority start and see what happens - maybe they really did fix something.

 

bugman, I didn't realize that you put in a deep cycle battery, if you want to try and fix this yourself I would suggest you;
1.) Buy a Delco battery (starting battery), checking the date code to obtain the newest one available (The warranty date code is located on the top label of the battery. The first character is either a P or S. The next two digits determine the month, the third digit is year and the fourth digit indicates the manufacturing plant. For example, P 094N means the battery was made in September 2004 in the New Brunswick factory.)
2.) Since you did not list exactly when ths started, remove the Priority Start and the Window Valet.
3.) Try it for a while, if all is OK then reinstall the Window Valet and try it for awhile again then, reinstall the Priority Start if you want. Just make sure you only do one thing at a time to isolate the problem. Rich