I created this new post in hopes of helping someone else looking to do this easy DYI project. I spent more time looking for a guide online than the project took to complete. I’m not too handy but I could not see paying the dealer a crazy fee to do this. People have asked what year the car is- it is a 2011 but should be accurate for all 997.2 cars.

Total time to complete the project 15 minutes.

Battery used Interstate MTP-94R/H7. I paid $170.00 and it’s the same exact battery the Porsche dealer stocks.

Tools Required
Ratchet
10mm socket for battery terminal nuts
13mm socket for battery hold down bolt
10” extension used to get to hold down bolt
2 each zip lock slider bags I used the HD freezer type.
Optional- Small flat head screwdriver, Rubber Mallet


Install procedure
1. I attached the car to power to ensure memory setting are not lost. I used a Porsche battery maintainer that I keep the car attached to when not in use through the cigarette lighter.

2. Remove cover over battery held down with 2 thumb screws. Next I used the 10mm socket and removed the positive battery cable. I slipped the zip lock over the cable and slid the slide closed to keep the car from shorting out. (I was feeding power through the cig lighter)

3. Repeat same procedure on negative cable. I don’t think the zip lock was necessary here but I used it anyway.

4. Next I used the 13mm socket on the extension to remove the battery hold down bolt. Remove the bolt and plate from battery tray.

5. Pull the vent hose out of the side of the battery and tuck out of the way. Grab the battery, tip it back and at the same time slide 1/4” to the front and toward the passenger side of the car. That gets the lip on the battery free from the battery tray lip.

6. Lift the battery out of the car. This battery weights 42.9 lbs but because it’s removed while you are leaning over from a few feet away it’s very awkward. I removed all my junk front the frunk. Put one foot in the frunk and lifted as I exited and it worked out but is an awkward maneuver.

7. Lower new battery into the well. Be careful not to catch any wire’s and once it’s in the battery tray tip it back and slide to the rear of the car and slide to the driver side.

8. Next lower the battery hold down plate back into position. Be sure to look at its orientation when you remove it so it’s easier to put back. I did not but figured it out without too much wasted time. Use a light to line up the threaded hole and hand tighten the bolt. Follow up with the ratchet with the extension and the 13mm socket to snug it up. Re attach the vent hose to the battery (passenger side) and insert the plug into the vent on the side without the hose (driver side). The plug is in one of the 2 vent holes on this battery. I had to use a small flat head screwdriver to pry it out and insert it into the opposite side. Gentle tap with a rubber mallet seats it flush.

9. Next carefully remove the zip lock off the positive cable being careful so it does not come into contact any metal. Place over positive terminal and use the ratchet with 10mm socket to snug up. These are very soft terminals and be careful not to over tighten or you will bend the battery cable side terminal ends.

10. Repeat the same procedure with the negative side.

11. I dated the battery with the install date bc this one did not have a sticker visible from the top once installed.

12. Reinstall the battery cover and twist thumb screws.

13. Close Frunk

14. Remove battery maintainer and start the car. If all went well like it did for me the car fires right up-no warning lights or memory loss..

Side note :
I also purchased an interstate MTX-49/H8 (AGM Battery) which I ended up returning. The online selector said it would fit and it was a higher CCA so if I could fit it, I wanted to.. I tried installing it with the same procedure as is listed above and it did fit in the space provided. It’s about 1 inch wider left to right. The issue I had was that the battery tray hole corresponding to the wider battery was not threaded for the hold down bolt and as a result I could not use the larger battery.



Old dealer installed battery dated 6/16. Note battery was not dead but after 5 years I change them so I don’t get stuck. Cheap insurance.

Battery hold down plate and bolt.

Néw battery installed. Positive terminal to the passenger side. So the new one went in upside down.

See the vent hose in this picture. Just pull out of battery and tuck out of the way.

 

Great DIY guide. This will come in handy for sure

 

An even more important detail of this procedure is that having the battery maintainer on will protect OBDII readiness for your next smog check. Porsches have been known to have a very difficult readiness reset after a battery change and an inability to pass smog due to lack of same.

 

- Excellent 'Write Up' & Tips
- However, I also own a 997.2 Turbo S, and my Positive Cable is installed on the Passenger's Side. I note from your pictures that your's is on the Driver's Side.
- MY 2012 997.2, and I installed the AGM 80ah Battery [Banner] & it was the exact same dimensions as of old battery
- In fact, the Banner AGM Battery had Porsche's PN stamped on the top of the Battery, and was the OEM 'spec' battery.
- So, I was curious why you could not install a compatible size AGM battery

Just some observations. [And, I've never thought about using the Trickle Charger to retain all of the memory settings.]

 

I did mine last year as well.. totally agree, it’s a bit awkward lifting that thing out. I was like oof.

 

- Thanks for the reply. It's appreciated.
- Great to share information & tips with others. Your's was very good & the Pics were great. [Done this many times, but still learned something reviewing yours.]
- I really liked the 'tip' of having the Porsche Trickle Charger attached before removing the battery to avoid losing 'memory' items/settings. Never thought of that - Would always just do the 'Drive Cycles'.
- I just ordered another "Banner" 80ah "Porsche OEM" AGM Battery, but it was from Europe [i.e. www.design911.com]. Hence, a premium for shipping. So be it. I've had great experience with that battery.
- They are the only ones that I've found who carry the above referenced AGM Porsche battery. Sunset Porsche used to carry them, but I spoke with them, and they've stopped.
- If I'd gone to the 92ah battery [which is what I wanted], I'd have to remove the battery box in order to relocate the mounting nut for the wider battery. I didn't want the hassle of pulling the battery box.
- As you may know: There's no need for the 'Drain/Vent Tube/Plug' on an AGM battery.
- Personally, I am not a fan of "Interstate", but it appears that Porsche dealerships are. Don't 'get that' since they don't always 'fit' correctly.
-Take care.

Thanks.

 

If I were to do it all over again, I'd go with Antigravity or some other lightweight lithium battery

 

Why do you feel this way ? I get 5 years out of my interstate batteries and change them before they go bad. The antigravity are great and I have several of their jumpstartees and power courses. The batteries are super expensive and this light weight does not attract me bc it makes zero difference to performance.

the cost is 3-4 times and I just cannot justify it.

wondering if I missed a good point ?

Thanks

 

Some people spend tens of thousands of dollars on carbon fiber to save the same 40lbs. Mostly though, I just want the best for my Porsche and also want the smoothest startup and such with higher CCA rating the restart safety feature is nice too.

unfortunately I discovered lithium car batteries just after I installed a brand new, as heavy as can be, h8 lead acid battery in my 911, so now I have to shuffle batteries between my cars so I can put the lithium battery in my 911 down in Florida. It’s currently in my Audi allroad (the lead acid battery that was in it will go in my mom’s cayenne whose bad alternator drained the battery all the way) ready to drive down to Florida. Start up is nice.

 

‘in other words:
Do you need to reset the codes for PDK, heated seats etc for a pdk car if you change the battery while the car was attached to -power during the process? If yes, do you use a scan code for those?
will you need to register with a scan tool the new battery?
‘will the Icarsoft POR V2.0 work for the above on a 997.S pdk ?
thank you

 

If you use the trickle charger nothing needs to be reset. Perfect time saver hack.

 

Thank you I did and the car and all systems seem fine after replacement of the battery.
However I understand that the new battery must be registered with a car with a scan tool.
I got the icarsoft POR v2.0 but it seems it cannot do this for my car a 2011 Carrera S.
Any suggestions as to how I can do this and which scan tool will work for that?
I understand this is a necessary step so that the new battery is optimally charged by the car at all times.

 

By the way I replaced the original Interstate Mega Tron 94R with an Interstate H7 AGM just in case it makes any difference.
Would appreciate any feedback as to how I can properly register this with the car's system and with which scan tool.
Thanks again

 

You can’t register it because it doesn’t require it. I had same question when I replaced mine years ago so I called the local Porsche dealership and was told you don’t register it.

 

Thank you Sobrut911 - It is really helpful to know nothing else is needed. Best regards,