GradecEngineering

Just sharing my personal battery experience:

I normally drive my '08 D3 daily. After sitting for six days it was a no-go. I jumped it and went back to my daily grind. From what I've seen, it had an impressively long life. I can conclude that driving it daily keeps it charged enough to not notice any depletion.

For peace of mind, I purchased a Walmart $123 H8 battery. Not sure who manufactures it, but the body looks identical to the original Varta, including the handles and vent port. The only difference is that it's a full inch shorter in length. I have 90 days to return it so hopefully all goes well.

Any other members using this cheap battery?

Hannibalacp82

I've had Walmart batteries in 2 of my cars with no issues for 3+ years. Just keep the receipt in the owners manual so you can find it if you need to do a warranty claim.

MP4.2+6.0

You got the small boy instead of the big boy. H8, aka Group 49 is the small boy fitment for mid size or mid power type Audis. H9, aka Group 95R, is the big boy. Another 1 to 1-½" longer but otherwise the same and both bolt right in the same space. Negative is as new its down on the order of 15% on reserve capacity and CCA. Good news is for auto crossing it takes 5 pounds out of what might as well be 4 million pounds. Probably hurts drifting too...

Seriously, yes close enough for most folks. Even in the smaller size, depending on which exact one you got, the quoted specs can be higher than the OE ones for the same size/group. But, if you want the max juice, then the big boy in a given brand gets the nod. FWIW Audi actually seems to have spec'ed both for the A8/S8 in North America, and it seems to vary randomly with year and even motor from looking at battery parts tables a few times--as in, not an automatic the W12 or S8 is always the one w/ the big battery as OE like you might guess. If an Everstart Maxx flavor from Walmart FWIW, likely Johnson Controls underneath, and in turn Varta's are commonly Johnson Controls with their stickering. See my response 16 in this thread, and the link to a table of underlying real manufacturers: https://www.audiworld.com/forums/a8-...ttery-2891990/

Big picture, per the link it usually goes back to the same three suppliers, so even the corner parts store, or these days a Walmart or Home Depot (theirs are Exide from buying one for the Mini S, which was Exide as OE) or others have either the branded supplier ones sometimes or store or fake brand names that really go back to the handful of true manufacturers. Ditto with the long time player here too, Sears, or Interstate as more a dedicated battery brand sold by indy parts stores. And in turn sometimes things like case detailing can clue you in on which manufacturer it was if you know the physical details.

05SilverA8

Johnson Controls has been the battery supplier for Walmart. I have had very good luck with my battery from Walmart so far but I do keep the receipt handy just in case.

Shark_V8

Just did some quick research and here's what I have -
#1 not enough information on the Walmart battery.

#2 OEM is 110Ah, ( 850A EN, 520A SAE). Capacity @110ah is what Audi uses to size the battery to the car/options. Cranking power is not the prime concern. Actually my A8 took ~ 400Amps at 32DegF to start. Just a quick spike.

#3 Quality control, battery construction and guaranteed power. Based on the complexity of the car, power regulation (and this past week), I for sure want to minimize any electrical risk.

#4 Back to Ah : 110Ah is a top rating spec'd on the A8. If the power is solid, the car will have no trouble sitting for weeks in Sleep Mode, or supplying the 7 amps I need to listen to the radio on the ferry ride. In fact it will do the better part of a day at that consumption. So it's all about meeting spec run times for all the modules, before load shedding occurs. Anything less you are under design specification.

With any other car, hells bells... but with the A8 (or any other Audi with Module #61) I would stick with OEM rated and also supplied.