997 Alternator or Battery issue

[aia]

Hi,

Started up and displayed "battery generator" warning light.

So dropped on the battery charger and after it finished disconnected it.

Used a voltmeter whilst the car was running and measured 13.7 volts.

Checked the belts all tight

Display didn't reappear.

So I either have a alternator on the way out,  or the battery is rubber ducked.

Question is; is there an age where the alternator gives up around the 10+ year mark.

If so any idea of the cost.

Any other clues or things to check.

Thanks

 

 

[Raven]

Is the car slow cranking when the engine is warmed up and you go to start it ....? like the car has low battery voltage 

 

[aia]

Hi,

Nope cranks well, my thoughts were the battery might be on the way out which triggered the light.

Otherwise, wait for an event to happen, would be interesting what fault is registered internally.

Thanks

[GC9911]

4 minutes ago, AIA said:

Hi,

Nope cranks well, my thoughts were the battery might be on the way out which triggered the light.

Otherwise, wait for an event to happen, would be interesting what fault is registered internally.

Thanks

Might be worth load testing the battery, most auto electricians will have a load bank to put on your battery, see if it collapses under load. In my experience alternators/generators are like all other machinery, they have a finite running life, how many kms on your car?

[aia]

Ok,

Its 88k, which is mainly country driving, car is only used every second day or sometimes sits in the garage for a week on a trickle charger when I am away for work.

Yes, probably load test is the way to go, or just sub out the battery given its at least 4+ years old.

I was more concerned if its the alternator give PCB will charge be more than a battery and a battery is easier to get where I live.

[GC9911]

Be surprised if it’s the alternator, definitely go the battery test first.  I did extensive battery testing for Optus as they have approx 35,000 batteries across australia to work out battery life & the economics of maintainance v replace on failure. We came to the conclusion that after 4 years just replace, especially if the batteries are in a constant/regular high ambient scenario. The higher the normal ambient/operationg temperature the shorter the battery life.

[Raven]

common fault on 997 gen one is the starter alternator cable failure  ........generally the first sign of it going is problems with hot starting ie slow cranking of the starter when the car is at temperature  .............I would give the rennlist forum a good search if it is a alternator then some one on there would have had it before also.... and generally there is a detail thread on the issue ...

[Zelrik911]

This Site has pictures. Replace 2 cables - Job from Hell.

https://www.6speedonline.com/forums/997/289189-3-8s-how-replace-alternator-cable.html

[aia]

Ok, I am curious whether others who have 997.1 on this forum have had the same issue.

Not an easy job, from looking at the URL.

Battery is over due for replacement, so that's step 1

[Raven]

The Alt and starter Cables are around $180 ,,,,but give every thing a good check before you purchase one ...

Another voltage drop issue can occur with the rust on the current bolt that runs through the fire wall ,,,if the bolt dose not have full contact you can get a degree of voltage drop from battery to the rear of the car eg Battery at 13,7 but large voltage drop to alt and starter  ....have a look at this thread some info on this issue ...

 

https://rennlist.com/forums/997-forum/986396-997-1-c2s-hot-start-slow-crank-finally-resolved.html

 

 

 

 

 

[Pokiou]

car batteries should be replaced every 5 years. Maybe your battery is loosing voltage over night?

[aia]

Yep, agree the battery needs changing out for sure.  Overnight not sure, when I am away it goes on the trickle charge so thats at least 2 out of 4 weeks per month.

Plan - put in new battery, drop in to Porsche and ask them to read the error code that would have been generated.

After then its a wiring job as suggested by you guys.

Thanks for the advice

[Francois]

Hi AIA,

I had the sluggish warm starts and replaced the starter motor and Alternator/Starter B+ cable. If you don't have these ignition issues, you're probably safe.

I can't recall seeing the fault you mention, so hopefully you don't have the same issue.

Hopefully the new battery will solve it

Cheers

[dan_189]

Starter/alternator cable wouldn't charge my battery on my 996. Often went dead before I replaced it (cable)  and got a trickle charger because if infrequent use. 

Battery is a good place to start.