Ac Delco Battery

1999 Tahoe 4x4 · December 16, 2007

Today I decided to change my 4 year old AC Delco Battery. I had the feeling it was getting weak and just wanted to be on the safe side. So I got a new one from the local pats store. However after I installed it, I needed to jump start the truck, since the new one seemed to have no life in it at all.

So my question is how do I decode the stamped in numbers in the battery? Since the numbers on the new one begin with 6A I suspect the battery could be of Jan 06. And would that be too bad? How is the shelf life of thise things? How much life should I expect out of my purchase?

Raymond Lowe · December 17, 2007

You got hosed. You are correct in reading that date code. Most battery manufacturers use a similiar code. I don't settle for anything over 3 months.

c4cruiser · December 17, 2007

Batteries do lose there charge while sitting on a shelf. If the battery you bought would not start the truck, you probably should have been on the phone to the parts store asking why you were sold a bad (dead) battery and wanting to know when they would be out with a new battery that works.

Is the AC Delco battery you bought labeled "Professional Grade"?? Some chain parts stores don't carry the Professional Grade battery line. The Professional Grade is sold and installed by reputable auto repair shops and dealers and is the top of the AC Delco lineup.

By any chance, did you do a load test on the battery to see if it was getting weak?

To find the build date: Year (0-9) Month (A-M,skipping I). 8C = 1998, March so you did get a January 06 battery. IMHO, that is beyond a reasonable date for a brand new battery.

I had the battery in my 99 Silverado replaced under warranty in May of 02. The one tht was installed is still working fine and showing no signs of reduced power.

Back in 1997, I bought a 92 Corvette. When I drove across country in 2003, I deceided to replace the original AC Delco battery simply as a precaution as I didn't want to risk a battery failure in some small town. When I took the old battery out, I gave it to a friend who put it in his work truck. It's still there, still starting the truck everyday. I did a load test on the battery; actually did threee in a row and it still had over 70% capacity left after the 3rd test.

1999 Tahoe 4x4 · December 17, 2007

Well, the Battery is not professional grade or at least it does not say so. Also it does not have the built in Hydrometer. The stamped-in info is 6AG11, the sticker says 046G. I got it from Pep Boys, a chain that is otherwise not my favourite, but according to AC Delco's website they were the only ones in my area that carry AC Delco Batteries.

I drove my truck there and bought and installed first a 78DT-72. That seemed to be brand new and wrapped in plastic on of many 78DT-72s that they had. But then when I was about to return the core I saw that they had a 78DT-84 on the shelf. I have the big CS144 alternator, so I got interested in that bigger battery and the parts guy was OK with me getting the newly installed ..-72 out of my truck returning it and buying and installing the ..-84. But with the ...-84 the truck would not start. Unfortunately this ..-84 was the only last one they had, so I agreed that they jump start me and I was ready to be out of there. It was luch time, I was hungry, I already spent over 1/2 hour at the store, so I easily convinced myself that everything would be OK. However after lunch and now with a clear head I started to worry. So what do you guys think. Will this one just work fine or should I go back and have them order a new one.

c4cruiser · December 17, 2007

I don't think any of the AC Delco batteries have the "Green Eye" anymore whether or not they are the retail-store battery or the Professional Grade versions. None of the Professional Grade Delco's that our shop installs have them.

The alternator is not designed to bring a battery to full charge from "dead" but if the truck was jumped started with no issues, you should be fine. If you have a battery charger, you might put it on for a few hours. Most chargers have the ability to lower the charge rate as the battery builds up to a full charge. Look for around 12.2 to 12.4v at the battery with the engine off, no key in the ignition and doors closed.

If you are concerned, let Pep Boys kinow that you are not convinced that the battery is good but drive for a week or so and check battery voltage with a DVM in the morning before you start the vehicle. If the voltage is showing the same value every time, you should be OK.

If you decide to get another battery from them, check the date code first; there's nothing to say that their warehouse wil have a battery that is any newer. It depends on how often that battery is sold against the last supply they got from AC Delco.

It is really up to you but I would not have accepted a battery that is going on 2 years old before it ever gets in my rig. Did they pop out the year and month on the warranty label?

1999 Tahoe 4x4 · December 17, 2007

Did they pop out the year and month on the warranty label?

No, they did not do anything. Surprisingly they did not even note anything on the reciept other than that it is a 78DT-84.

My point is; that let's say if you or you guys think that I have only "lost" let's say one year of the total life of the battery, than I won't make a big deal out of it. But if you think that this battery could be seriously damaged while sitting on the self for almost two years (probably most of the time discharged) then I would go back and try to persuade them to order a brand new one. (Like I said they don't have it on stock any more, I got the last one that they had)

BTW: I could not find any reference on the Internet in regards to differences in lifespan between AC Delco Professional and the Regular line. Does the Professional Grade perhaps have stronger terminals etc?

The OEM battery in the truck broke the positive terminal and spilled acid after 3 years. I got this last battery (the one that I just gave up to Pep Boys for a core charge) at the GM dealer about 4 years ago (could not find it in stores around where I live). I have just checked my reciept as I'm writing up all this right now. Man, I just see I paid $119.- for it and that was a Professional 78DT-72.

I guess this is one of the few times where I should have gone to the dealer to buy parts again.

redsled2007 · December 17, 2007

Put it on a "trickle" charge over night(at least 8-10 hrs) and then if it fails to start take it back. The warranty starts the month you purchased the battery, not when it was mfg'd.

silversport · December 17, 2007

aren't the Professional grade batteries AGM (Glass Mat)???...I know GM went to these around 2001 (My Corvette has one) and my 2000 Escalade I just picked up has one of these...I can check the date code now...coool!

Bill

c4cruiser · December 17, 2007

What you got out of the deal is a battery with a longer warranty period. The "-84" refers to the number of months of warranty. You got a 7-year warranty with this new battery. What you had was a 72-month or 6 year warranty. The Professional Grade batteries use a code like 5Y, 6Y, or 7Y at the end of the model number to show the warranty period. The "78" refers to the group size. Professional Grade batteries also get a 50 month free replacement, the other grades don't.

What's interesting is that when I used the AC-Delco parts lookup feature for batteries using your vehicle description was that your particular battery model number did not show up at least with the -84 numbers. The webpage showed 78DT-6YR and 78DT-7YR but also showed a 78D-xxx model. The "DT" refers to "Dual Terminal" Is that the type of battery you bought? AC Delco batteries are also available as either top post or side terminal types and have a slightly different model number.

It could be that AC Delco batteries made for sale through retail outlets have a different model designation. I don't think I have ever seen a Professional Grade AC Delco battery at local chain auto parts stores like Shuck's, AutoZone or such.

In any event, once the battery is fully charged, you should be OK. As long as you have the sales receipt, if you ever need another battery, just go back and then ask for one that has a date code within 3-4 months of the current date. IF they can't provide it, go to a reputable auto repair shop and get a Professional Grade version. You don't have to go to the dealer for that battery; they will charge a good $50 to $60 more than a independent shop.

c4cruiser · December 17, 2007

aren't the Professional grade batteries AGM (Glass Mat)???...I know GM went to these around 2001 (My Corvette has one) and my 2000 Escalade I just picked up has one of these...I can check the date code now...coool!
Bill

There are AGM versions of the Professional Grade batteries. I had one in my 02 Vette but it didn't last long. I had an electrical drain and it drained the battery to the point where it would not take a charge. The previous owner of the car had it installed under warranty and it was only 2 years old at the time it went south. So I went back to the standard PG battery for the replacement.

Strange, but I can't seem to find any information on AC Delco AGM batteries on their website

1999 Tahoe 4x4 · December 17, 2007

The "DT" refers to "Dual Terminal" Is that the type of battery you bought?

Yes, it is a Dual Terminal Battery. 78DT-84. I'm connecting it at the side terminals. I like the dual design for jump start purposes.

The prevoius battery was 4 years old and was working fine. Basically, I replaced it just to be sure. But now I'm wondering if I ended up with a more reliable result.

The 84=7Y / 72=6Y makes sense. I actually thought it might be AMP-Hour reading. Shows how great this forum is to get info.

silversport · December 18, 2007

c4cruiser...thanks for the info...

Bill

1999 Tahoe 4x4 · December 18, 2007

c4cruiser...thanks for the info...

Special thanx c4cruiser for the extensive and very professional information as well. Everybody else, also thanx!

Meanwhile I contacted AC-Delco and this is the response that I got:

"... To determine the manufacture date for your battery, look for one number followed by 2 letters that are melted into the black plastic at the top of the battery. These are usually located near the positive terminal.

The number indicates the year (i.e.: 6 = 2006, 7 = 2007), and the first letter corresponds with the months of the year. (A = Jan, B = Feb through M = Dec. Know that ‘I’ is skipped because it looks too much like the number one.). The last letter stands for the manufacturing plant ..."

They did not answer my question about shelflife of their batteries so I'm going to further bug them with a phone call. I realize my efforts might be a bit overkill, and therefore a bit silly, but I guess that's just part of my way of being an GM enthusiast.

silversport · December 21, 2007

I'm assuming I'm just missing it but two of my vehicles have "Professional" Grade Delcos but I cannot find the "stamped in plastic" numbers for the build dates...I see above should be near the positive terminal but I don't see it there...both replaced prior to my purchase of the vehicles...thanks for any help you care to share.

Bill

1999 Tahoe 4x4 · December 24, 2007

I'm assuming I'm just missing it but two of my vehicles have "Professional" Grade Delcos but I cannot find the "stamped in plastic" numbers for the build dates...I see above should be near the positive terminal but I don't see it there...both replaced prior to my purchase of the vehicles...thanks for any help you care to share.
Bill

It seems like not all batteries are stamped. There is also a code on the tag. On mine it says 046G. I belive 6 here is the year and G is the month. I belive this tag says when the battery is best to be used by. So in this case 2006 July.