2008 Saab 9-3 Sportwagon 1.9 Tid 150 Alternator charge

[Petemate]

Charge rate only 13.1-13.2 volts at the battery, both at idle and higher revs, with or without lights HRW aircon etc on.

Tomorrow I'm going to check for earth cable and other cable/connection problems, but if it turns out that the reg is defective, has anyone ever managed to replace the regulator with the alternator still in situ? Looks like it would just be possible with my slim hands. The alternator is around 3 years old and IMHO should be ok regarding windings, commutator etc.

TIA
Pete

[carrera]

I don't know about the access issues, but can you check the voltage at the alternator output - that will point to a wiring or alternator problem

[Petemate]

I don't know about the access issues, but can you check the voltage at the alternator output - that will point to a wiring or alternator problem

Thanbks carrera. Not checked the wiring earths etc yet but back from shopping had a good look again 'down there' and definitely insufficient room to wriggle the screws/tools/reg. So if, once I have stablished earthing etc good, there is still only 13.1v at the B+ on the alternator, I'll be putting a new one on.

[sgould]

Have you checked that your voltmeter is accurate?  These things can go off with time.  If it has an internal battery, it that OK?

[carrera]

That's a very good point. When the internal battery is getting weak the voltage readings start to drift. New battery in the meter first I think 

[Petemate]

Have you checked that your voltmeter is accurate?  These things can go off with time.  If it has an internal battery, it that OK?

Thanks Will - meter is OK. Found the problem - overheated positive post, resulting in voltage drop where the large lead enters beneath. I'll need to apply some heavy duty repair, fortunately my lad has a BIG electric iron. I found 14.2v at the alternator B+. Also 14.2v on the starter connection. So I prodded the cable and found 14.2v, but only 13.1 on the 3 way post fitting.

Thanks for all the input!

Pete

[carrera]

Nice cheap fix then, thanks for posting back with the solution.

Last time I did something like this I think I just used a butane torch to get heat into the cable core, the solder flowed well enough.

Just make sure it is the connector and not broken cores within the cable.

[sgould]

 

[Petemate]

Nice cheap fix then, thanks for posting back with the solution.

Last time I did something like this I think I just used a butane torch to get heat into the cable core, the solder flowed well enough

Cheers - I'll probably do something similar. We'll see what state the wiring is where it goes into the post 3-way connector - not sure I can pull the cable far enough to fit a large ring terminal. Hopefully I can repair it at the post (my lad also has a nice Max torch. Ideal for this sort of thing)

[Petemate]

All sorted now. Short heavy duty pos cable from Halfords, one end cut orf, spliced into the main cable (not enough to pull through to cut and refit)

Job's a good un.

[Petemate]

IMHO a crimp like this on the main cable from the positive terminal of the car battery is a very poor design. As well as for the current to the starter, it is also the path for the alternator to charge the battery. I think a very similar layout on a lot of cars.

As shown in a previous pic, that crimp was on the underneath of the terminal 3-way fitting. I suppose that the application of some anti-corrosion treatment by the harness manufacturer prior to crimping would have been too much to expect. 😡

[carrera]

I am reliably assured / educated that crimping cables gives a better electrical connection than soldering, the pressure creates micro welds between the cores and the increased wire surface area increases the current carrying capacity.

Other chemicals will no doubt interfere with the micro weld process, though of course the conditions when new do not remain constant through the service life. I haven't heard too many occurances of this type of failure, so suspect you were just unlucky.......... but at least you didn;t waste money on a new alternator 

[Petemate]

I am reliably assured / educated that crimping cables gives a better electrical connection than soldering, the pressure creates micro welds between the cores and the increased wire surface area increases the current carrying capacity.

Other chemicals will no doubt interfere with the micro weld process, though of course the conditions when new do not remain constant through the service life. I haven't heard too many occurances of this type of failure, so suspect you were just unlucky.......... but at least you didn;t waste money on a new alternator 

Thanks carrera. As you say, I was probably unlucky but I reckon there will be a few other cars out there with potential problems.

I am intending to eventually replace the ring terminal on the end ofHalfords finest piece of cable with something like the atached pic. IMO better to be OTT than stranded (no pun intended)

Thanks for all the inputs everyone.

Pete