944 Turbo battery charging issue

[atticlab]

Hi.
Just getting to grips with a newly purchased 1986 944 Turbo (which is generally in very nice condition). The car has an immobiliser device.
..
I was not sure if the battery was charging correctly so this morning with the car on my drive, I......
- measured volts on battery with engine not running (just over 12v)
- measured volts on battery with engine running (up to about 13.5v)
- measured current (with a DC clamp) into battery with engine running - started about 5A then settled down to about 2A after a few mins running

So...I though all was fine.

Car started fine and I went for a 20 mile drive and I noted that the dashboard voltmeter seemed closer to 12v at end of journey than at start - no fluctuation with revs.
Parked car for 15mins then it would not restart without a booster battery.
..

Any ideas/suggestions?

Many thanks

Keith
P.S. I also have a 924S that could be used for comparison experiments.

 

[JamesO]

New battery time I would have thought.

 

[DavidL]

For all the checks it sounds like the battery.
If the alternator voltage regulator gives up you would see less than 12v on the gauge and everything gradually stops as you go on further - been there!
The gauges are only a guide and not that reliable. I tend to see closer to 14 on the gauge most of the time.
Could be a mega drain but 15mins really isn't very long.
Could you borrow a battery to check or if its got a warrantee take it back!

 

[PSH]

I would also say new battery needed , my volt gauge only just reads over 12 volts and has been like that since I've owned the car which is over 14 years now.

Pete

 

[ukmastiff]

Not saying it isnt the battery because most likely it is BUT an alternator will usually put out just over 14 when charging a 12 volt battery. A knackered battery with maybe dead cells will effect that though as electricity is a strange beast. The average home multitester can be wildly inacurate anyway so it probbaly is putting out 14 plus for all we know.
I have a Professional Fluke for work which is good and a cheapo one I bought when I mislaid the Fluke , the cheapo Maplins one sucks [:'(]

A new battery will be your friend come the winter anyway so you cant lose by buying one. If you dont drive her regularly get a battery conditioner too , best money ever !

Mas

 

[bmnelsc]

The symptoms are much like my 91 S2 - battery was poor - although it would last about a week when parked. The symptoms for voltmeter, etc. are the same.

With a new battery - no more problems tho the gauges read low compared to before but system test shows everything is fine.

 

[atticlab]

Thanks for all the helpful advice.

The best bit is that I just discovered the battery is still in the guarantee period - so I am definitely going to try and exchange it

 

[944 man]

Keep the receipt to yourself and ask them to test the battery. When they declare it defective, as they certainly will, pull out your receipt with a flourish and an irrepressible smile!