The windows are one thing that must be manually fixed when new battery is installed. Fix is easy.

Turn car on to ACC

lower window all the way down, release switch then push switch down for 3 seconds and release
raise window all the way up, release switch then pull switch up for 3 seconds and release
turn car off then back on, windows should work normally

 

That worked! Got everything sorted in 60 seconds. THANKS!

 

Advance Auto sells the Diehard Platnium 900CCA, 1000 CA, H8 , 160 minute reserve battery for my 2012.5 for 238.99 (with core exchange) less $10 Rebate (good through Feb ‘23) . The install is free so just showed the installer the above helpful instructions and let him do it (and had him install the CTEK hard wire connection looped through the plastic shield as shown earlier at the same time). $20 tip and I was in/out in 20 minutes.

 

Diehard makes great batteries. I ended up with Interstate this go around, because it was easier for me to source here, but I used Diehard for years in many other cars and they were surprisingly durable in a lot of extreme conditions.

 

I have used Diehard batteries for years and been pleased with them. But regardless of how they are branded, all car batteries in the US are made by one of three manufacturers: Exide, Delphi and Johnson Controls.

 

See attached image. Takes the guesswork of how much battery life is left. Also tests charging system.

 

My OEM battery in my 991.2 just died at exactly 4 years (without using a battery maintainer). I replaced it following these instructions. I also used the Duracell battery as in the OP, but the part number now is AGM49. The OP is for a 991.1, but everything is the same on the 991.2. I did the swap without using a battery maintainer and did not lose any data upon starting the car. Thanks to @daberlin for sharing these instructions. I don't think I would have attempted it without them.

 

died early, usually 5 years is time to do it,,,probably depends who made the battery,,not sure who makes Porsched OEM

 

BANNER battery in Austria.

 

And East Penn is another. A top quality battery. They have a web site with technical info.

I had a list of batteries showing who makes them for all of the chain stores and I am sure that changes from time to time.

 

That’s too general a timeframe Bob. Heat takes a toll on batteries and we have our fair share here in SoCal. My garage regularly registers 90 degrees F in the afternoons during the summer.

I replaced the battery on my 991.2 at the 4 year mark. It still had some life left in it, but why wait for a surprise?

DaveGee

 

U R correct..I didnt think of all the climate differences,,5 works for me here in N. CA

 

Yes, lots of people think that cold temps kill batteries without realizing that the heat is just as damaging.

 

FWIW, regardless of what I said earlier in this thread, I upgraded to an H6 40Ah Antigravity at the end of 2019. I didn’t think I needed the 60Ah because I daily drive my car and 911s don’t have high parasitic losses. Works great. It only sat on a lithium ion tender for long periods during the pandemic.
Tip for those who don’t like the idea of standing in the trunk. Get a strong broom handle, thread it into the plastic handles on the battery and with a friend, lift it out (unbolt the brackets first!). Putting in the lightweight Antigravity is a breeze you can do one-handed. Oh, and the lithium iron phosphate chemistry isn’t prone to ignite or explode. Losing 20+ lbs of lead weight up high just underneath the base of the windshield is a plus.

 

The general rule is for every 8C (14F) in temperature increase over the standard temperature of 25C (77F), your battery life is cut in half.

The other reason is possible overcharging IF your charging system does not reduce the charge voltage as the temperature increases. I know it works well at colder temps where I was at 14.8 to 15.0V at 6C (43F). And I know the charge voltage reduces as the temperature increases, just didn't take note of it.


I was a bit concerned that I was charging at 14.8V even at 6C (43F). At the time I didn't know my 991 came with an AGM battery.