Of course I can swing by any local shop and have them test my battery, in which case most will tell my I need a new one, LOL! But, other than that, what are some basic warning signs? I know I am due for a new one, as I am at 51k miles and 5 years. Over the last month, the start-up growl has tamed significantly, and today, for the first time ever, it didn't start on the first crank.
CATTMAN

 

I live in South Florida, so if it isn't dead by the 3 year mark, I replace it. Period. Cheap insurance against a hassle later.

 

With 5 years and the symptoms you describe, you are very close to the end of the battery.

 

Alright, I am going to try to find an Interstate MTP-91, unless anyone tells me otherwise.
Specs:
700 CCA
85 months
$125-$150

Yeah?
CATTMAN

 

My car is a 2006 with a production date of 12/23/2005. Until early April the battery was the Moll factory original. When I went to start her up on April 10th in the morning it was "Anejo and lights a flashing". Every instrument gauge & light were going crazy so I quickly popped the hood & pulled the key out. The old Moll gave up her last bit of voltage.
Two hours later I installed a Sam's Club Energizer Battery group size 49 for $82.28. Since this battery was a little bit longer I had to install the clamp on the last hole in the tray. The hole is not threaded therefore I had to place a stainless steel washer and nut (m8 x 1.25 mm) (w/Blue Loctite) under the tray in order for the bolt & clamp to thread into.

When the car was restarted some of the instrument lights (ie: PASM, ABS) were still on & the clock & radio were wrong. I turned her off & restarted & drove around the block & everything was reset except for the driver's window. Driver's window reset was a simple, hold down the button for 10 seconds & she was as good as new.
Possibly my only warning of a potential battery failure was this past week when I would turn the lights out on the PCM unit it would come back on after 2-3 minutes. This would happen 3-4 times after I first turned out the lights. Now with the new battery in (and as in the past) when I turn off the PCM lights they stay off.

I've been an avid user of a battery maintainer & a distilled water re-filler so I can't complain about the five years that the Moll lasted.

 

Well, I installed an Interstate MTP-91. Cost $109 at batteries plus. The vent line had to be moved a bit, but it's in and working fine.

This is going to sound bizarre, but the car feels so much better now. Not just on startup, but driving, it feels peppier and more responsive. I can't fathom why, since not even the ECU reset as we maintained power to the vehicle throughout. Might the elec system somehow be responding faster to throttle, etc.? It's bizarre, as I said.

The AC blows stronger and colder, too, which is nice on these 95F days in ATL.
CATTMAN

 

Odssey also makes a group 49 gel cell which is 95AH and a group 94R which is 70AH. I haven't bought one yet, but Batteries Plus tells me that the terminals are on the correct side.

ChuckJ

 

It is funny how we sense other improvements when simple replacements or fixes are done. I thought my previous car ran a lot better when all that was done was a few leaking gaskets in the engine were replaced, but it felt more powerful and tighter. Hence placebos in studies, and why so many HP improvement claiming potions and tweeks sell so well.

 

Yes, and newly washed cars run faster too. The old battery might have required a higher alternator parasitic load.

 

This is exactly what i did too.

 

Mine dies in 3yrs and 4 mos. It was replaced under warranty with a technician actually coming out to my home and installing it with a PIWIS to reset everything and make it right...simply awesome.

As far as warning signs..it started to crank a little slower, and as you say John it didn't start on the first crank once and I knew maybe it was going bad...3 days later it was bad.

Dave

 

What the 997 needs is a volt meter. It's amazing how much health monitoring of the electrical system with one. During start you can monitor how low the battery is drawn down. In the Corvette, if you're getting down to 10.5 to 11 volts on startup, you're about to run into trouble. If you're only getting 13.5 volts when charging after a startup, you know your battery will not give you the full measure of its capacity. I've had 9 Porsches and always missed having one. I may add one to this one.

ChuckJ

 

Cayenne has volt meter on the dash.

 

I'll bet I can add a PLX Devices module to my OBDII/ and custom sensor Chrono Pod. This would be cool, allowing me to read volts on my version of the sport chrono.

I may test the viability of that by seeing what Durametric data is available on volts.
CATTMAN

 

Just bought this:
http://voltminder.com/buynow.htm
Plug it into the lighter socket and hopefully it will tell me battery voltage on start and charge voltage. I'll let you know if it's worth it.

ChuckJ