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battery, starter motor, or the other wire bit...

michaelbbwalker

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Joined
23 Nov 2016
Messages
88
haven't really driven my 2005 997S much at all over winter, I've tried my best to take it out once a week or so just to keep it ticking over though... last few times the battery is nearly dead after a week, looking at other forums / posts on google, people saying they leave it for weeks without any issues?
is my battery likely to be knackered, or starter / other cable bit that needs replacing?
I had (well the car did) a hartech rebuild a couple of years ago, the starter was replaced then and also I can see on the invoice "wiring harness 99760701804" which I can see is the wiring harness for starter motor and alternator, but I read that the replacement part when this fails is thicker or something, does anyone who has had this replaced know the part number of the later (better) part?
I also have read countless mentions of Bosch s5 batteries being a great replacement, I don't know what's on the car at the moment but does it sound as though my battery may be on the way out?
 
I have to fit the Moll battery on my car for warranty reasons and I am on my 3rd in 8 years , they are rubbish especially if you lay the car up over winter.
If your Battery is the Porsche specific Moll battery and its 3 or 4 years old I would ditch it and change for a better make unless of course you subscribe to the Porsche warranty then you don't have that option. Check the earth strap as they have been known to go high resistance.
 
nope no warranty here!! I will check what type of battery it is in the morning, can't be arsed going out there this late :D
 
Just fitted a Bosch S4 80AH starts like a dream after years of will it wont it on a cold winters morning
money well spent
:thumb:
 
Anyone measured the volts on their battery.

Mine doesnt seem to be more than 12.2V after a long run when I would assume fully charged and more likely to be 12.6 volts.

If left for a week or two it shows 11.8v which should mean a dead battery but it starts first time without hesitation.

My volt meter doesnt need a calibration as I've tried it on the wifes car and the volts are where you would expect them when fully charged at 12.6 volts.

Seems very strange. Voltmeter suggestes the battery is finished but it starts first time???

Any suggestions I m not the best with electrickery :?:
 
@ michaelbbwalker

Get your local garage to do a battery test .. charge test and a discharge test .

It could be the battery or a drain and a drain will tend to kill a battery .. batterys dont like going totally flat and thats where the Moll fell over .. it didnt recover like some other makes .

Bosch S5 :thumb:

The most obvious is the battery but it makes sense to get all options checked .

You have had the starter motor and the main lead replaced .. thats the other place they can cause problems but mainly with hot start .

There is another but you have the wrong symptoms for a power dist fault so im discounting that .


@ Steve997

An alternator will never fully charge a battery .. only a trickle charger will .. i cant remember the exact specs but its something like 80% charged and it will rapidly fall off chargeing it much further .

11.8 will start a car no problem but is a little low , you have to remember its the amps that start the car .. the pushing power if you like thats stored in the battery .

A battery is Approx 2.1 volt per cell .. but that is new and fully charged .

One test i would suggest .. start the car and let it idle , turn on lights and main beam , heated seats , radio etc .. put a large load on it then measure the battery with your meter .. 13.2 or above its ok .. about 13 and your alternator is pretty tired .

Less than 12.5 and it needs to goto a garage !
 
Appreciate the help. Will carry out the suggested test. Thanks for the help.
 
I checked earlier, its an exide (premium!), never heard of them. .. where can I get a bosch s5 then, if anyone has a link to the correct one that would be handy... after I get a battery test of course...
 

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A local autocentre - Bosch, halfords or Quickfit etc might do a free battery test
 
Car Parts 4 Less or Tanya sell Bosch batteries
 
Thanks for the info guys will stick a new battery on the list! Wasn't sure which was the correct one to buy...
 
Halfords stock the Bosch S5 for the 997.

plenty of branches about so should be easy to get one
 
Ok... so while I've been on holiday I asked my dad to start the car every few days so it didn't go flat, I guess the cold weather has made things worse as apparently last time he tried it wouldn't start.
Should I ask him to pop the lid / frunk or whatever and leave it unlocked til I get home in a few days so I don't have to go through the crap to open the frunk with a battery etc.... the car is garaged anyway...
Also what is a suitable grounding point for when I do jump start it? Is there one near the battery as I have a starter pack so the cables aren't very long on those, think I've seen some metal bars near the battery? Or do people just connect to the negative battery terminal, it does mention that in the manual...
 
Well you learn something every day. Dermot, why is it that an alternator won't fully charge the battery?
 

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