Installed DieHard AGM Battery
 

Installed a Sears DieHard AGM battery today! Fits fine and has the required vent holes for the vent hose that is on the OEM battery! Yep AGM's can vent if overcharged and as with normal batteries it generates hydrogen. Prepared a PDF and quote a marine source warning that even AGM's must be vented!

As most shade tree mechanics there are often some tricks on the install. This has several! Had to check my 2014 Service Manual several times and as usual you sometimes get a clue but not an answer! To remove the large power block from the positive terminal, the Manual states: "Remove Clips!" No mention of where they are and looking around the confined area was no help nor was it obvious. Finally tried an approach with a screwdriver that worked! The PDF has many pics and one shows where to put the screwdriver!

This G48 size is Sears model number 50748. The OEM Delco conventional battery is model number 48PS. They both have recessed terminals needed to properly locate the power block. The CCA (Cold Cracking Amps) @ 0F for the Diehard AGM is 760 amps. The OEM Delco is 565.

Pricing was interesting. Received an email with a special discount price of $133 plus tax. Called the local store and it was $176 plus tax. The store could not match the price and told me to buy on the Net and pick it up there -which I did. Picked it up at the store in the afternoon!

The PDF with many pics of the install is: http://netwelding.com/Battery_Issues.pdf


https://cimg8.ibsrv.net/gimg/www.cor...5c71848420.jpg


DieHard G48 AGM Has 760 Amps CCA (Cold Cracking Amps) @ 0F. Note pic From Ad Shows 700. The Delco OEM Battery is 565,

Great post! Many thanks.

Excellent information... thanks for posting. :thumbs:

RE Sears Diehard AGM
 

OP,
I was price comparison shopping a couple years ago, and decided on the Sears Diehard AGM too. I was also pleased to see that I could buy it at a further discount of about $35.00 by paying for it online, then going to pick it up @ the Sears Auto Center near my home with the confirmation number. As I recall, the price was very good versus the equivalent dealer brand and the Interstate brand.

This very interesting. I just checked here in CA. My battery has been a dog and now is saying to replace. Looks like its now $106 and 115 out the door. :) Thank you

The price on this DieHard is much lower than comparable batteries at AutoZone and Advance Auto. Just checked and their AGM that fits the C7 is close to $200.

I just ordered for the hell of it. Since I bought my car I have always felt the battery was a bit weak. Here is a screen shot of what I paid. :)

My battery has had a low voltage, ~12.4, since I have had my C7, which will be 3 years in October. It has always started the car even after 2 1/2 week vacations but thought I'd replace before winter. I do not use a charger. More difficult to replace than anticipated so would not want just anyone trying! Glad I did when I had the time and it was not dead! :lol:

AGM batteries like Optima (which won't fit because the top configuration will not accept the large power fuse block) and Odyessy may have more CCA power but the Diehard has significantly more than the OEM Delco. The CCA (Cold Cracking Amps) @ 0F for the Diehard AGM is 760 amps. The OEM conventional lead acid Delco is 565.

I was looking at one from AutoZone but that was $176 for about the same CCA as the Diehard. AutoZone has an Odyessy but it has only 723 CCA, weights more at 48 pounds and cost $249. Less CCA for more weight and money! After looking at the Diehard and OEM today the pic looks like the Odyessy should fit as it has the required recessed terminals. The hold down will fit its flat top but not sure if the power fuse block will snap in place to secure properly as it does on the OEM and the Diehard.

Nice writeup, thanks.

Nice homework! Be sure to use AGM charger if needed. They behave differently than a standard charger.

Thanks. Used my CTEK 3300 on AGM setting to fully charge the new battery. It was on about 20 hrs when I installed it and indicated a full charge.

Bought the CTEK 3300 when I first got my C7 to see if it just wasn't fully charging the battery and causing the a low voltage. It was no help and still read low when the surface charge was depleted. Probably a weak cell. But it has started the car fine for almost 3 years. I just didn't want to take a chance before this winter and was waiting for a sale on an AGM battery.

Had an Optima in my C6 and have a Yellow Top Optima in my Street Rod (which does stay on a charger.) However as I noted, the Optima top post configuration will not hold the large power block that connects to the positive terminal.

I had not used the CTEK charger on the C7 since that one time in 2013. It is a DD and although I don't use it every day, when I do it is typically a ~40/50 mile drive so it gets fully charged.

OP, thanks for the thread.
I picked up the same Die Hard battery about two years ago for my C5. That solved any battery issues I had with the C5. When I replace the battery on the C7 I too will go with a AGM, Die Hard.

Battery Replacement
 

Jerry,

Great write-up. :thumbs:

That's the most complete description I've seen and certainly one I've saved.

Thanks,

Rich

Jerry- I agree with you, it is alittle more involved then I anticipated as well. With my car down as I do my SC install I figured I might as well upgrade. Here is an interesting fact. While in the car I tried to charge it and the charger came back with a "replace battery" message. Last night after I pulled it out I put it on the bench to charge and it looks like it is fine. Damn car. LOL

Just an update on the DieHard performance. Drove the Vette yesterday (~50 miles round trip) to go to the store. Checked this morning (after the surface charge was depleted) and the battery, for the first time in ~3 years, read 12.85 volts!

The Delco, which I have not returned yet (they did not charge me a exchange fee but said I would return it and will when driving the wife's SUV into town) was still reading 12.47 volts sitting on the garage floor!

I noticed the dash voltmeter when driving finally was just below 13.5 volts, lower than it has ever read, it was usually ~14 volts. Assume the altenator control system was trying to get the weak cell(s) to fully charge, an unachievable task!

Total time to change the battery was just under an hour (including time to take pics for the PDF.) Expected I would have to index the windows as I did when replacing the battery in my C6 . Did not, they are fine. About the only thing it did not "remember" was the car was left in Sport, as always, so had to change from Touring where it started. Also had to reset the radio to play my SD card in shuffle mode when the car starts.

Interesting thread...Jerry, what's the significance of your findings? I'm not quite seeing what you're findings are. Was the Delco not taking/holding a charge?

My C7 battery has always read an OCV of ~12.4 volts from when I got it in October 2013, well under the 12.8 to 12.9 volts it should be. Had the dealer check the one time I was there responding to a GM notice to have the diff fluid level checked. The diff was fine and they said, as expected, the battery was OK. They did not remove it and run a load test etc, but expect they don't have the equipment. Also considering removing the battery is a PIA would expect if they knew that, they would not be eager to do it! Mine was the 1st C7 my local dealer had seen! They had just had a mechanic C7 certified when I went for the diff fluid check. I bought the car from a large dealer with a sizable allocation.

In fairness the car has started fine for ~3 years even after several 2 1/2 week vacations. I don't use a charger (although I have the equivalent of the GM charger I bought early on to see if that would help the voltage-it did not!) Probably a weak cell(s.)

Since it was ~3 years old and before it might fail this winter, decided for $133 sale, getting a better AGM battery was a prudent. Much better to replace when I had the time and NOT when it failed.

Jerry,

I'm guessing you're going to see similar resting voltages (around 12.4) on your DieHard in a few weeks or months. Many modern cars have "battery management software" that don't allow the alternator to constantly charge the battery while running, but only when it's depleted to a specified level. I suspect its both for fuel economy reasons (reducing the alternator's parasitic effect) and to protect all the electronic systems in today's vehicles.

I traded a Jaguar F-Type to purchase my C7 last June, and the Fs, all had AGM batteries, which showed the same 12.2-4 resting voltage levels. It was a constant topic of conversation on the F-Type forum. I did a lot of testing by driving around w/ a voltmeter connected, and the readings would only spike to 13v + sporadically, w/ occasional brief spikes to 14v or so.

Jaguars explanation was always that's the way the "battery management software" is intended to work. I'm guessing the C7 is similar, and your Delco was normal.

I went to test drive a C7 a month ago, it had been on the dealers floor, and the battery was dead.

I just wonder how many batteries get ruined on the dealers lot prior to purchase, these batteries are not the deep discharge types.

Did you get a car off the lot?

Great write-up Jerry. Saved the PDF file for future reference. :thumbs: