jimcabc

I've got a 2012 base Boxter which I bought new about 2 years ago. It now has 8k miles on it so I don't drive it everyday. I've has zero problems with it until last weekend. Last weekend I tried to start it up and you would have thought the ECU blew up. Ratcheting noise from back of car, ABS and PSM fault alerts in the dash, the radio turned itself on and the rear spoiler went up. A couple more attempts to start and the electrics totally died. So here I have a dead car with the top down in the garage and 2 1/2 hours to the nearest dealer.

Phone call to Porsche roadside assistance who arranged a flatbed tow to the dealer. The dealer calls at the end of the day and explains the entire problem was a dead battery and the drama and light show on the dash when I tried to start the car was a usual symtom of a very low battery.

Apparently no warranty on the battery but at least the tow was free! The dealer actually recommended replacing the original battery with an Interstate MTP 91 which has a two year replacement warranty and then prorated the year after that. Picked up the car on Tuesday and have driven it another 200 miles with no problems.

A couple of questions:
1) Is the experience I had (fault lights, accessories turning themselves on) really typical of a low battery on these cars? If I heard just the ratcheting sound, I would have quickly concluded it was just a low battery
2) I failed to ask the power rating of the battery that came out of the car. The Intersate has 700 CCA and 875 CA, which would seem more than sufficient for the car, but is it more powerful than the battery that came out? The manual is not helpful here as I couldn't find any reference to the battery power rating.

Thanks for any insight here!

Jim

2012 Boxster
Dark blue metalic/black

Gone
1987 Porsche 911 Cabrio
3X black

tinman

I had the battery on my 06 987S die, I had left the trickle charger off for a while, so I got a Porsche battery from the dealership, again, I did not drive the car and after about a month that battery was dead, I didn't want to hassle with trying to recharge it, even though I have a Craftsman battery charger, I did happen to have a Sears Diehard which I had purchased for my friends 2001 BMW 330i, I didn't scrutinize the details of it, it was exactly the same size and the same vent tube positioned in same place so I went ahead and put it in, it has worked fine since, and I am more diligent on using the trickle charger (Porsche)....the DieHard battery was pricier, it was "International", as I suppose it was aimed for foreign cars. I'm not saying what I did was right, but I've been ok with it for years now. Now if I can only decide what to do about my IMS situation, as my car has less than 8K miles on it.....

jimcabc

Tinman - Neglected to say I bought the Porsche battery tender with the new battery!
Die Hard batteries are good in my experience - years ago I used to build them at the factory... They are still made by Johnson Controls.
Sorry about your IMS problem, that's a bigger problem.

its about time...

I got my '08 987S in January, 2012 and bought the CTEK Multi US 3300 right away, but the (I believe original) battery died a little more than a month later. The local dealer actually stocks the Interstate battery. I put it in and no issues since. The CTEC looks identical to the Porsche charger; there are some that believe Porsche buys them from CTEC.

LexVan

This.

jimcabc

its about time: The Porsche Multi-charger I bought was made by CTEC.

ClintonM3

I have this plugged into my car whenever it is parked.



Any modern automobile can have the same problem. 8,000miles in 730 days is about 11 miles per day on average. I was told 20+ miles per day is needed to keep the battery sufficiently charged. Modern cars all now have at least 30 to 40 control modules in the car (something like a 7 series or S class can have double that), many with internal clocks, or is drawing power one way or another. Once the battery level drops to a certain level too many times, no matter what you do, drive it or charge it, sometimes the battery level just won't climb back up.

I've had similar experience with BMW's, check engine light, ABS, 4WD, DSC, xmas lights, etc. With the Porsche, I had issues with the keys.

After reading some posts, most people find that the first symptoms are generally with the keys and frunk malfunctions.

jimcabc

I may have had one warning a couple of weeks before the battery failure. After a highway drive of almost 100 miles, when I got home the rear spoiler was up. I finally was able to get it to retract by pressing the dash spoiler button a couple of times and shutting the car off and restarting it ( I forget the sequence).

tayls77

I have a new to me 07S, are you saying that if I only drive it a few times a week I need to keep it on a charger? Most weekends it will get out for a 50-100km, yesterday I put 450km on it? The 328is it replaced only had two batteries over 15 years under the same circumstances?
Thanks for the help!

07 Boxster S
97 BMW 328is
12 Acura MDX
12 GMC Sierra

Macster

No direct experience with the newer model cars but I've heard from the techs the newer cars can act like they are possessed and do everything but vomit split pea soup if the battery is real weak. (Or if when the engine is running the alternator is not working properly.)

Makes sense. All those subsystem controllers need juice to work and many are designed to monitor battery voltage to ensure they have proper voltage to operate correctly. Since some of these subsystem controllers are safety related they'll log an error and turn on their warning light if they detect battery voltage below some threshold that can possibly affect their proper operation.

As for your question about battery specs for the battery for your car, my advise is you should check with your local Porsche parts department regarding what is currently the capacity of the battery specified for your car. When my Boxster battery finally died I went to buy a replacement at the dealer parts department. The SM looked up the part number based on my car's VIN and found the factory had issued a new part # and the new part # referenced a larger battery, Physically larger -- longer -- and with more AH and CCA that the original OE battery.

I bought the battery and it fit very nicely though I had to move the hold down out one hole to accommodate the longer battery.

the_vetman

No.

Battery maintainer (do not use a charger as they can fry batteries if left on too long) should be used if the car will be left alone for 2 or more weeks. 1 week of inaction can kill batteries if they're already weak, though it should be fine if the battery is up to snuff.

One very important note: our stock Moll batteries have these cells that should be checked and replenished (i.e. they're not sealed shut) ~yearly. Pull the sticker off at the top and you'll see these Philips head plastic screw caps. Remove them, check the fluid level, and add distilled water as needed. This is something that only a few do unless they know about it, and is a significant source of premature battery deaths.

lee88

Good tip. I keep mine on a tender given it's stored in winter and even during other 3 seasons I drive it occasionally. I didn't realize these weren't sealed, maintenance-free batteries.

terbiumactivated

+1 vetman, a lot of people think batteries are sealed when upon closer inspection one sees almost all of them allow access to the cells. Charge a battery with even a tiny bit of plate above the acid and you'll fry it dead every time. Non maintenance of battery cells will kill a battery quickly and using a tender IMO is going to exacerbate internal acid fluid loss.

tayls77

Great thanks for the advice and tip!

Alan Smithee

This may be a dumb question - do those using a CTEK keep the frunk closed and the car covered? The CTEK instructions warn of the need for adequate battery ventilation; for medium-term storage I would rather have my battery expire a year earlier than provide an easy nesting place for rodents.

Thoughts?