mgordon18

Has anyone replaced a 991 battery without "programming" it and had any weirdness?

If it only reduces the battery life, I could buy 4 aftermarket batteries for the cost of a single dealer-installed battery. So even if the life is reduced to 2 years, I'd still get 8 years from $800 rather than the 5 I'd get from a dealer-installed battery...

Sidvicious7

Porsche_nuts

Sounds like he was trying to do you a favor by charging you about $800 for a freaking battery. Crazy. Buy an AMG battery and put it in yourself. Save about $550. Take the wife out to an expensive dinner and then buy her a gift too for being such a good wife. Or buy the kids a nice holiday present. This programming stuff is just a scare tactic to separate you from your hard earned money.

Your SA sounds like a grinch wannabe.

CSK 911 C4S

On the reprogramming thing.

The only comment made when I asked about this subject was if you replace with the same TYPE of battery .... reprogramming is not necessary.

When you change types then you have to tell the car so it will not over/under charge.

I changed mine when the time came last year w/o reprogramming and everything has been fine.

Sidvicious7

eagle1960

2013 C4S. Replaced battery DIY about 8 months ago. No "programming ", no issues.

SeymourButts

LexVan

No. But they have bonus programs based on profitability and high customer survey scores. In general. I'm sure there's exceptions.

Dkk16

In reference to commissions, I don't know about the Porsche model, however Toyota does. In most if not ALL dealerships, service is by far the biggest revenue generating branch of the dealership, parts is second.

I snuck in once on a impromptu Toyota service advisor meeting. They were getting reamed out for not hitting Monthly goals...seriously. I feel bad for the uneducated person, even my wife, who say would go into a Honda or Toyota place for service and totally get taken advantage of. I guarantee it happens every day. I can't imaging Porsche is much different. I can tell this just by reading posts on Rennlist. They (try) put the fear of god into you and your wallet.

Having said all that, I'm sure not all are like that. They are there to provide quality service to the Porsche owner with oem parts.

Sorry for the rant.

rporzio

AGM is a new term for me, is that battery standard equipment in a 2014 C2? Thanks, R.

LexVan

Yes. All 991s have the new AGM battery technology.

eagle1960

Just to clarify. AGM batteries have been in commercial use for about 20 years. A big reason they are seeing use in passenger cars now is their deep cycling ability which makes them a better choice for auto stop starting vs a flooded cell type.

john45in

Got the AGM noted in #4 above about 10 months ago and put in in myself. No issues, no required programming, no lost settings. The hardest part is standing in the frunk (bent over) and lifting that 55 pound chunk from between the feet into the well.

myrr

Another option for the money saved.... lithium perhaps? Benefits abound....

BlueNorther

from battery university (not making that up):

Absorbent Glass Mat (AGM)

AGM technology became popular in the early 1980s as a sealed lead acid battery for military aircraft, vehicles and UPS to reduce weight and improve reliability. The sulfuric acid is absorbed by a very fine fiberglass mat, making the battery spill-proof. This enables shipment without hazardous material restrictions. The plates can be made flat to resemble a standard flooded lead acid pack in a rectangular case; they can also be wound into a cylindrical cell.

AGM has very low internal resistance, is capable to deliver high currents on demand and offers a relatively long service life, even when deep cycled. AGM is maintenance free, provides good electrical reliability and is lighter than the flooded lead acid type. While regular lead acid batteries need a topping charge every six months to prevent the buildup of sulfation, AGM batteries are less prone to sulfation and can sit in storage for longer before a charge becomes necessary. The battery stands up well to low temperatures and has a low self-discharge.

The leading advantages of AGM are a charge that is up to five times faster than the flooded version, and the ability to deep cycle. AGM offers a depth-of-discharge of 80 percent; the flooded, on the other hand, is specified at 50 percent DoD to attain the same cycle life. The negatives are slightly lower specific energy and higher manufacturing costs than the flooded, but cheaper than the gel battery.

Most AGM batteries are mid-sized and range from 30 to 100Ah. They can also be found in UPS, big and small for stationary and deep cycle use. They are commonly built to size and are found in high-end vehicles to run power-hungry accessories such as heated seats, steering wheels, mirrors and windshields. NASCAR and other auto racing leagues choose AGM products because they are vibration resistant.

...

AGM is making inroads into the start-stop function of cars. The classic flooded type is simply not robust enough and repeated cycling causes a sharp capacity fade after only two years of use. (See BU-806a: Heat, Loading and Battery Life.)

As with all gelled and sealed units, AGM batteries are sensitive to overcharging. A charge to 2.40V/cell (and higher) is fine; however, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages). Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell); a direct replacement with a sealed unit could overcharge the battery on a long drive.