BTW, if you live in the deep southern part of the states...

Just completed the replacement of the OEM battery on SilverBox, a 2008 987. The OEM battery was about 5 1/2 years old and started showing dying signs this past weekend. If you have not done one on your Boxster you should know that the process is easy and straightforward. I selected an ACDelco 94R Profession Absorbed Glass Mat (AGM) battery as the replacement. Here are the steps I took:

1. connected a CTEK3300 battery maintainer via the cig lighter. The remaining steps were done while standing in the ftrunk
2. removed the battery compartment cover via the two twist knobs
3. removed the vent tube from the battery and move to the side
4. loosened and removed the battery retainer clip located on the lower left (passenger) side of the battery- it is bolted to the battery tray and holds the battery in place by the lower lip of the battery
5. loosened and removed the negative battery cable from the battery post; cleaned the inside of the cable connector with a wire battery brush and put the connector in a small plastic bag to keep it from contacting anything (remember I had the CTEK3300 on)
6. loosened and removed the positive battery cable from the battery post; cleaned the inside of the cable connector with a wire battery brush and put the connector in a small plastic bag to keep it from contacting anything
7. slid the now disconnected OEM battery slightly to the left and tilted slightly back so that you can get the lower lip of the battery out from the tray retainer edge and lift the battery up and out. I had positioned a step ladder next to the front of SilverBox so I could just rotate and put the battery on it rather than try to either step out of the trunk while holding the battery or bend over and place it on the floor.
8. checked the condition of the battery tray and found it to be in excellent shape, so nothing needed to be done
9. lifted the new battery into the battery tray, being careful to ensure the lower lip of the battery slid under the back retainer edge of the tray and slid the battery fully to the right to ensure it is up against the end of the tray
10. removed the bag from the positive cable and positioned it over the positive post on the battery, tightened it down
11. removed the bag from the negative cable and positioned it over the negative post on the battery, tightened it down
12. sprayed both the cable ends and posts with battery maintainer and sealant
13. repositioned the battery retainer clip- it needed to be in one hole to the left of the OEM location since the 94R AGM is about 1 inch longer (but the same height and depth as the OEM) . The tray is predrilled and threaded for larger batteries so this was no issue and did not require any special bracket, etc. Securely tightened it down and checked to ensure no battery movement.
14. Reconnected the vent tube to the battery.
15. Reinstalled the battery compartment cover and latched using the two twist knobs. [Got out of the ftrunk ]
16. Removed the CTEK3300 and started SilverBox. It turned over and started instantly. Because the CTEK3300 was connected throughout the entire exchange there were no codes on start up and nothing that had to be reset.

The entire process took less time than it is taking me to write it up . I saved about $136 over the cost of just the OEM battery replacement from the Porsche dealer (plus of course what ever the charge would have been to install the battery by them). The ACDelco 94R Profession AGM battery has 800CCA, 100RC, 400LTA, is 'nonspillable', 100% maintenance free and comes with a 36 month full free replacement. After firing her up I drove to a local auto store who took the OEM off my hands and gave me some store credit for the core even though I told them I did not purchase the battery from them.

If you have never replaced your own battery I hope this may be of some help.

Great write-up, Jeff. I agree, it's an easy DIY and saves you the equivalent of a few tanks of fuel in labour charges. Z

Guenter
2014 Boxster S
GT Silver, 6 Speed Manual, Bi-Xenons, Sports Suspension (lowers car 20mm), Porsche Sports Exhaust, Porsche Torque Vectoring, Auto Climate control, heated and vented seats, 20" Carrera S Wheels, Pedro's TechNoWind, Sport Design steering wheel, Roll bars in GT Silver
[www.cyberdesignconcepts.com]

Thanks Guenter

I live in S. FL and batteries have a typical lifespan of about 24 months b/c of the heat. In fact, that's what the battery testers @ Pepboys/Autozone/etc. will print out for you if you ask. I now buy Bosch-brand batteries... b/c they have a 36mos replacement warranty and a 96mos pro-rated warranty. I've had 2 batteries died on me (once in the Boxster (26mos) and the other in my Audi A4 (18mos)) and took them back to Pepboys, they look up my info, looked at the mfg date and gave me a brand new one at no charge. Just make sure you keep a copy of the receipt/scan it so the receipt ink doesn't fade on you after a year.

Interesting Cris. We have it pretty hot here in Vegas as well. It was my understanding that the AGM handle the heat better (as well as vibration) than flooded batteries. I was going to go with an Optima in SilverBox since I have had great success with them in other vehicles, but the Optima would require a special mounting kit. That is why I went with the 94R which required no special mounting and is an AGM. Then again my OEM got 5 1/2 years out here in the desert, probably helped by my use of the CTEK when not driving her.