Porsche Enthusiasts Club Forum

Car had a new battery around November last year so 13months ago. Never seen higher then 13v on the dash but never had a problem with low power so I just assumed the dash gague isn't working like it should.

Battery is under a 3 year warranty with the rac.
Car has immobiliser which I think prevents the car attempting to turn over if there's less then 10v, I can have power 2 lights e.c.t but it won't turn over. No rev bounce just a dud noise and block when turning the key.

Car was with barks for a few months and they had a few issues with the battery needing charging.
When iv been out in the car sense at night iv been getting 13.8v with headlights on e.c.t read from android app which is linked to the ecu.

Other week when setting up the laptop in the car to do some data logging and update ecu I had power on but not the engine running as I didn't want to piss off the nabours. The car wouldn't start after about 10 mins. This is with no lights on just key turned to far right, a quick jump start got the car running.

On route to London weekend b4 xmass on the m2 my abs light came on and the Apexi revs started getting a bit crazy over 3k rpm.

I tried to turn the Igintion on and off see If it would get ride off abs and ! Warring light. Couldn't turn the car back on. So I pull on to the hard shoulder turn on the hazards couldn't get the car to start again. Evenly I tryed without the hazards on and pop ups down. Still no luck. AA couldn't come out for around 3 hours so I got my dad to meet me and give me a jump. By the time he got there I had no lights nothing. A jump and everything was on and read 12.9v which it stayed at for the rest off the journey to London.

I got the rac to come out the next day and test the battery. They came to the conclusion it could be the autonator

I got halfords to check the battery as well and they think the battery is fine.

However iv checked the connections everything seems tight and clean.
So thinking it could be the voltage regulator I found that there the same part on vw golf at half the price and a cheap one is £12 and as a ford part there £6!

The autonator has a plastic heat sheld which requires getting under the car and in the weather we been having iv chose not to. So dispite remove everything above I put it all back.

Now hears the thing iv been mointer the voltage a lot more closely and iv only got 10.4 v b4 start up day time driving at motor way speeds iv been get 14.2v /13.9 with lights on

At town speeds I'm getting a mix between 12.9/13.8 after every drive I check the voltage at the battery and it 10.4 or 10.6v

So would I be right in thinking that this to low ? And should be 12v autonator is in fact working as the voltage increase with the engine running.

There's been two times where once started iv seen the voltage drop from 13.8/14v down to 10/11 pulled over and started the car again the voltage has then gone back to 13.8v

Battery is a Bosch 4 star 60ah

My car is a turbo looking in halfords is should be higher 74ah

Is it worth swapping out the battery, ? Could there be a lose connection that's not letting the battery get back up to charge, or a battery not been able to hold more then 11v charge?

Car was checked for a drain with doors shut and alarm on we had a reading off 0.04 which I believe is very good so no drain issue

Sorry for the long post and rabble

My Alternator started playing some time ago, just loosing voltage randomly, and one Sunday evening just died totaly i went with reconditioning old unit with new bits inside. As far as i'v been told, mine had inner bits worned out, not the regulator.
Other thing - check negative cable going from battery to body, if it's old, it might have dodgy connection between claps and cable itself.

Changed the negative cable just cas I had a spear, wound it up tight and wound it round as I placed it as well.

I think Battery should be 12v before start up?

How much was your recon cost

i meant connection from cable to cable clamp, mine was copper, and it oxidized inside.
Battery voltage before cranking should be just over 12v, while cranking it will be lower.
My local company got it sorted for £60 at friends/neighbours rate. They sent it to a company located in Markyate, don't know which one.

I had the same problem some years ago with a Montego Turbo and the battery was new but a shorter Amp hour.An electrician at the garage told me to try a bigger ah battery...this cured my problem.

Just had a look in the owners manual and it states 63Ah for both standard 944 and Turbo, so you are a bit down on cranking current there. Perhaps a beefier battery would help...especially in this cold weather.

I'm thinking off Bosch s5 100 74ah a lot more crank should fit with battery on the outside clip. It's 3kg more
£80 of eBay via euro car parts

It would seem like the current battery not taking charge

Check carparts for less website probably cheaper, they are the same company I think.

There's a few pences in it via eBay which seems a cheap outlet for Boths website. But I think direct from euro would prob make it Easyer to get the warranty honoured.

Ordered a battery from euro parts on eBay £80
Went with s5 100 so if its not battery at least it's a larger one which should help at some point.

What sort of distances are you driving as short distances will soon discharge a battery, especially with the lights, HRW, heater etc on in this weather

Manly 60 miles from home to London

With a few short journeys in between. Battery turned up today at my home. Ordered it yesterday so 24h which is pretty good.

Won't be able to fit till Monday or so next week

Battery is fitted now getting 11.8 via autoronic app. On start up getting 14v

Iv only been on two short 10mile trips and the voltage works its way down to around 12.8/13.1
If I turn off lights it will jump by 0.3/0.5 turn them on again it will reduce by the same amount

On the dash I don't see anything more then 13v and most off the time it's just over 12v dispite the app reading much higher. It's always been this way. Iv not had any more issues with starting or abs light coming on and iv covered around 300 miles.

Do I have a problem? Or do these cars run fine around 13v I'm not getting any issues. So I will keep an eye on it and swap out the voltage reg when I change the turbo

Seems the battery hasn't solved the issue. Today I had 11.8v then 14v running which dropped to 10.7v and abs light came on, pulled over and turn the engine on and off. 11.8v then 14v but this time it stayed at 14.2 v the whole 10 mile journey and was 13.5/13.8v on the way back.

This was day time driving so no lights on. Seem the autonater works then don't and puts out slightly differnt out put at times. Would this most like = voltage regulator ?

I had no trouble starting the car this time as the battery it self hadn't dropped just autonator output.

I think I may just put a re built unit in when the turbo is out however £15 voltage regulator MIT just fix it, still could just be temperamental connection

Hi Terry

I recently had similar charging problems. In the end I had to replace the alternator. Tried a new voltage regulator but no joy. So I have a new voltage regulator here I can post to you to see if it fixes yours.

Just PM me your address if you want to give it a try.