Battery replacement

Hi I only use my car (996 X50 Turbo 2003 model) at weekends. I noticed a few months ago the starter seemed to be running slower each weekend but still without any problems starting. Now I have been put on a project abroad and am away from home for two weeks stints so now my weekend car is twice-monthly car. After the first two weeks away - you guessed it - car won't start although the alarm etc. still runs. I am back again day after tomorrow and want to buy a battery on way home from airport. My questions are: 1) When I change batteries should I keep power to the leads by using jump leads - i.e. will anything suffer from momentarily the car having no battery at all? 2) There is a pipe off the side of the original Porsche battery which I think is for acid leaks or something? I have never seen this on any other car and I am not intending to buy a Porsche replacement battery for various reasons. Okay just to leave this off the new one? 3) What do forum readers recommend for AH value (80?), start up power in Amps, reserve etc. 4) Looking at car from front facing windscreen is positive/plus left or right (this is important as I am buying the battery before I next see the car!!) 5) Which dimensions? The car lives in Spain but is UK reg/RHD if this makes any difference. On a general note with a new battery should I be okay leaving the car two weeks at a time without use? Many thanks Sam.

Hi, I replaced my battery a few weeks back. You need to switch the ignition on before you disconnect it or the alarm will go off. I just went to Halfords and bought the one they recommended. It was slightly shorter (left to right) but the clamp simply bolted into the next hole in the battery tray. No idea about the numbers, but do warn that your battery will suddenly die with no warning, like mine did. I paid about £110. Cheers

My battery went last week too, with no warning (thought it may be something else at first, as even after charging it all night it still wouldn't start, but no - definitely dead battery). I went to OPC Wilmslow for a new one, £177. Very easy to fit; the overflow pipe on the side connects to the battery but the bit of the battery it connects to doesn't seem to actually allow anything to flow out (i.e. you could leave the pipe off if you want, it doesn't seem to do anything useful). Keep the ignition on while you swap it to stop the alarm going off, and other than having to reset the clock and the trip computer resetting itself, there will be no ill effects at all from momentarily having no battery. It's an easy job to fit as well, only one bolt on the left holding the battery in. :thumb:

Insert key in ignition and turn to position 1 before disconnecting old battery, otherwise alarm likely to go off and since you are right next to it your ears will bleed!! Personally I would also leave the drivers door open, and the window down, so there is NO chance of some freak occurrence locking your keys inside, but I'm a bit of a saddo like that. My battery also came from Halfords - HCB096 (google that and you will find it) fits fine, from memory has higher Ah and higher CCA than the OEM item had. 4 year "no quibble" guarantee, cost £100 in Dec 08. My car is a Targa, non Turbo, but assume they take same battery?? Suspect the tube you refer to is a breather tube - if the new battery is fully sealed and does not have a breather hole just ignore the tube. Hope that helps

No battery is ever "sealed" in that sense. It means maintenance free (do not need to check or modify the electrolyte). All acid batteries will outgas, that is the chemistry of recharging, however "sealed" units are designed to react the released oxygen and hydrogen back to water. Excessive hot or cold may require the unit to breath also (via escape valve). In a "normal" car this is not usually an issue, the battery vents into the engine space. In the 996/997 etc the battery is mounted on top of the fuel tank and various electronics and mechanicals that would not appreciate acid. Additioanlly, although not airtight, the space under the front bonnet is not ventilated and hence a build up of either poisonous or explosive gases may dwell. A decent battery will probably have tiny little stoppers in the side (if the holes are already apparent), just pull out the one on the driver's side (RHD) and connect the overflow pipe. Note: if a plate fails and shorts internally the battery will boil. With no escape valve it will explode. Without a pipe, this boiling acid and vapour will vent into the battery space and not safely to ground.

Dont waste your time getting a Porsche over priced replacement, they are for want of a better word Shite, my car has had 2 fail in 3 yrs, im about to take the last failure back for a refund as it lasted 7 mnths ! I replaced mine with Varta Silver F18 Heavy Duty Car Battery 85AH SIZE 019 800 CCA Cold Cranking Amps / 5 Year Warranty , 99 squid delivered off ebay, you cant beat that price .. item 230423391317

Unless you need an "official" battery for warranty etc, don't bother with a Mol (the Porsche brand). Very expensive and not really very good. Plus only 2 years guarantee. Get a Varta (it is a rebadged Bosch, but cheaper) 315*175*175 mm 85 Ah and 800 CCA FIVE year warrany Varta Silver 585 200 080 (short code F18) = Bosch Silver 0092 S5 010 (short code S5 010) Go to somewhere like ManBat = approx £80 http://www.manbat.co.uk/

Crikey! Just when you think you've spotted a thread that your tiny brain and single figure IQ can actually contribute to, along comes GT4 and makes you feel about 6 inches tall... :floor: :floor: uh: PS Just kidding, don't stop, place would be poorer and less interesting without. ETA - just off outside to check my breather tube is correctly fitted!

Yeah, but no, but ...

Seriously though, if the unit does have overflow holes on both sides, the hole opposite the overflow pipe MUST be stoppered (else there is little point in the pipe - the overflow will just vent and spit and dribble out of the other open hole!)

When you all refer to battery failure, are you referring to an actual dead battery ie no power at all? I seem to have a central locking problem after leaving it standing for nearly three weeks. It locks, then immediately unlocks and beeps twice. The manual identifies this as a central locking fault. I took it on a long run two weeks ago and the central locking worked fine immediately after, but then failed again afterwards. With the ignition off the voltmeter is reading just below 12v and when running it reads 14v. The 'test' lens on the top of the battery is nearly all black, which indicates the battery should be checked, but I can still start the car fine, not even any noticeable drop in power.

+1 best 996 battery for the money, performance and warranty, this would be my first choice. (Varta Silver F18).

Thanks everyone for all the replies - very useful. I am definitely going to go for Varta - the reason being the easiest place to buy batteries in Spain is Carrefour which stock their own brand, an economy brand and Varta! By the way it was definitely a battery failure not central locking - the starter noise I could actually here turning over slower and slower each week. Finally when it wouldn't start the dash showed only 9-10v as did my charger. Even with battery recondition mode, charge mode, trickle mode etc. nothing would get it over 10v so its knackered I think is the technical term!! However the only thing nobody replied on is which side, left or right, should I buy the battery with the positive on - I had this issue on my Mondeo ages ago, I bough the wrong handed battery and the positive lead wouldn't reach to the positive terminal - or with the Porsche doesn't this matter?

Bonnet up, standing in front of car looking at battery, terminals on mine are on the two corners nearest to me and the +ve terminal is on right.

Have a look at the battery fitted to your carand buy one with the same form then you know it will fit. Oh and to look at the battery its just a job of lifting the bonnet and lifting up the bit of plastic at the back between the boot and the windscreen