Battery life

[roygarth]

Put new Porsche battery in exactly 2 years ago. For last few months I've not used car but started it up for 15/20 minutes every 2/3 weeks. This weekend not enough juice to turn engine over.

Is it:
1) It just needs a proper charge and all will be well again?
2) Battery is fu#@ed and I need a new one?

Thanks
Piers

[muzaa]

I have a 993 and if i leave it in the garage for a couple of weeks it wont start, and I had a new battery less than 4 months ago. So I bought a battery charger to get round the problem, not ideal but it works.

[Steve_T]

Suggest you drive it more often - problem solved

[muzaa]

I cant aford the petrol

[leeme3]

Had a similar problem myself with a 3.2. Got a battery conditioner from Halfords for about £20 which connects really easily and just keeps it topped up enough to mean you can start it. Really recommend it, and cheaper than a new battery if it works!

[roygarth]

Thanks guys, but is my battery too far gone ie will it hold a charge? I know it's difficult to be sure.

[ian_dorrian]

2 weeks in cold weather and the finest of Varta's batteries was unable to generate anything more than an alarm siren and a clicking solenoid.

As my 993 lives in a storage yard while we are in rented accomodation this means no mains power for the optimate so I now recommend the £20 12V solar panel and diodes from Maplin hardwired to the batttery combined with seriously crossed fingers for sunny days.

Alternatively disconnect the battery so the current hungry PA1000/2000 alarm can't drain it.

[nel]

roygarth said:

Thanks guys, but is my battery too far gone ie will it hold a charge? I know it's difficult to be sure.

Only way to know is to charge it. Give it an overnight trickle charge then see if it'll still start the car a couple of days later. Yes - you're OK, no - it's shagged.

[ian_dorrian]

P.S. battery almost certainly shot.

[cyberface]

Funnily enough my 993 (the Battery Slayer of Sevenoaks) killed another battery two weeks ago. Having got through a few, my bet is that it's a combination of cold weather and the drain from the OEM alarm gear. Unless it's a daily driver, batteries will become consumables.... I've normally had good luck driving at least twice a week (even if it's just Saturday and Sunday) but if you leave it a couple of weeks then the battery will be drained slightly.

In cold conditions, this is enough to knacker the battery - you're more likely to get away with 2 weeks disuse in summer.

Once the battery is completely deep-discharged, it's normally scrap. Once the plates get sulphated the cells become useless anyway. It's easy enough to tell - whip the battery out and put it on an automatic 'intelligent' charger - if the charger reckons the battery is full after 10 mins of charging, then it has sod-all capacity and is useless.

Another tip is to buy big good batteries. I tried a Halfords '3 year guarantee' 'calcium technology' special (of the right size and capacity for the 993) last summer and it died two weeks ago. I've now got a Bosch Silverline battery, more or less the same price anyway (80 quid inc VAT)

I have a solar powered trickle charger for the dashboard, but it appears that the 993 disconnects the cigar lighter when the ignition is off - therefore presumably my solar charger is worthless? Anyone here know how to mod the 993 so I can trickle-charge the car through the cigar lighter without leaving the car insecure??? (parked on the street you see)

[Andy_Clap]

I think if you charge it properly it will be fine.
I'd recommend using something like an Optimate, they're a fantastic bit of kit and don't just charge and maintain the battery, but will desulphate and recover badly abused ones. I've used my Optimate to recover batteries which have sat in the corner of the garage for years.
I've also got the Halfords trickle charger, and whilst a neat little tool I'm not sure it will "service" the battery like the Optimate does.
If you've got any friends who are bikers it's odds on one of them will have an Optimate they can lend you, or better still just buy one and leave it connected to your car.

Cheers
Andy

993 Targa

[muzaa]

So if the battery manages to run dow all the way that will knacker it, is taht right? So if I leave mine for period of two or three weeks I would be better disconnecting the battery.

[cyberface]

muzaa said:

So if the battery manages to run dow all the way that will knacker it, is taht right? So if I leave mine for period of two or three weeks I would be better disconnecting the battery.

Probably - the above point about Optimate battery conditioners reckons you can bring these sorts of discharged batteries 'back from the dead' - however you may find it more aggro than it's worth if you have to leave the car parked outside for a few weeks in between drives.

Definitely drive more often if possible! There used to be a product called 'Discarnect' which was a hand-operated connector between the battery positive terminal and the car's positive loom connector - a simple twist removes the connector and isolates the battery. It was sold as a supplementary security device - you can take it off the car.

One thing to note with this - third party alarm systems and some car radios may dislike being repeatedly connected and disconnected to the battery, though I can claim that the Hamilton & Palmer OEM systems on the 993 don't have a problem (having had many battery discharges in my 993s).

Secondly, if the car is left off-battery for more than a small amount of time, any adaptive settings in the ECU will be lost and the car will run very roughly when you reconnect and next fire it up. If you leave the car for more than a month then the tappets may drain and the car will run with a loud tappety ticking noise. It will sound like the car is shagged - however it takes around 5 minutes idling to refill the tappets with oil and the noise should go away. Don't rev it before the engine sounds smooth! Once the oil is fully warm, then take it on a full-load run (e.g. 4th from just above 1200 rpm to redline) to give the ECU some data on ignition timing, etc.

If you're going to leave the car for more than a month, then I'd suggest the more sympathetic method of turning the engine on the starter with no spark until you've got some oil pressure before firing the engine up properly.

[aceparts_com]

I'd recommend one of those dis-car-nect things

[superlightr]

you know the radio/torches that you have a handle to turn to recharge/top up on the battery - could a similar thing be used for a car battery emergency top up to get you going?

[cyberface]

superlightr said:

you know the radio/torches that you have a handle to turn to recharge/top up on the battery - could a similar thing be used for a car battery emergency top up to get you going?

Theoretically possible, but you'd have to be bloody fit to provide the necessary energy

[roygarth]

cyberface said:

Definitely drive more often if possible! There used to be a product called 'Discarnect' which was a hand-operated connector between the battery positive terminal and the car's positive loom connector - a simple twist removes the connector and isolates the battery. It was sold as a supplementary security device - you can take it off the car.

Correction! There is a product called Discarnect. I started my company, Richbrook, with this brilliant product many moons ago!

www.richbrook.co.uk/pages/batterycutoffswitches.html

Best way to buy is mail order from Demon tweeks 01978 664466 or online at www.speeding.co.uk
Price is £9.95.

Shameless plug over!

[ian_dorrian]

just ordered one....

[nel]

roygarth said:

Correction! There is a product called Discarnect.

Excellent little device - I have one on my occasional-use Golf. However, one caveat. If you use this on your porker (or anything else of significant value), then technically the alarm is disabled and theoretically the insurance could bitch. In practice the immobiliser would still stop the car being nicked if the crooks reconnect the battery, but the alarm wouldn't sound when they entered the car.

[Andy_Clap]

nel said:

the alarm is disabled

Does anybody know if Tracker works with the alarm disconnected? If Mr.Baddy just towed it away would Tracker be able to raise the alarm?