Alternator not charging?

[Schm565]

Hoping someone can help with this... Slightly puzzled - car (1.4 tdi) not used for a couple of weeks , started fine but alternator light came on and stayed on. On way back from short trip, steering packed up, clearly not enough power to run the power steering. Never had issue with it charging before. I’ve charged the battery and tested it with the engine on, no increase in volts suggesting it is indeed not charging (alternator light still on). 
 

It just seems a real coincidence that this has happened after not using the car for a while. Could the battery be the problem? It is quite old but then even so surely it would show as charging when tested with the engine on(?) 

 

thanks in advance for any suggestions!

[mrgf]

Very difficult to say whether it is or is not the battery as the Fabia hates worn batteries anyway so replacement is most likely desirable. 

If it IS the alternator, the battery will run flat in no time if the car is used with lights etc. You will also most likely get other glitches/faults pop up as it dips too low. A bad alternator will probably have killed the battery anyway, if overcharging but if undercharging, it might still be salvageable but still, best to replace it!

 

Is it possible to try one of those little alternator test things? They are usually cheap and have lights suggesting if the alternator is faulty, how much charge the battery has, etc.

Below, is one you will find on eBay (Copy and paste it in eBay search). but they are found anywhere, really. Lidl or Aldi sometimes do one, as should Halfords, etc.

 

AccuSpark LED 12 volt Battery and Alternator Tester

[Breezy_Pete]

Presence of auxiliary belt confirmed?

 

[mrgf]

That would kind of present issues!  😀 Funny, I didn't even think of things from that perspective... Thinking mainly about the battery and alternator.

[Schm565]

Yes the belt is there. I’m thinking it must be the battery because all was fine 2 weeks ago when it was last driven. Surely the alternator couldn’t have packed up whilst the car was parked for 2 weeks? 🤔
I wonder if the battery is worn, could that cause it not to accept charge (?) And  presumably cause the light to come on, steering to fail etc

[Breezy_Pete]

What is the voltage between the battery posts?

 

Best bet is to borrow a known good battery that will fit (any that physically fit, with the terminals the right way round). If that doesn't show an increase in voltage when the car is started, you can be fairly confident that it's not the battery that's at fault.

 

What year is this car? Have you looked at the alternator fuse?  Generally the leftmost stripfuse in the battery-top fuseholder.

[Schm565]

The battery is showing 12.31 volts. It’s a 57 plate, the fuses (no 1 on top of the battery as you say) looks ok.
 

I’ll try swapping with the battery out of a little Agila , it’s recently been changed so I know that’s a good one., although it is a smaller capacity than the one in the skoda, hopefully that won’t cause any issues

[Breezy_Pete]

Battery voltage is a little low, but not hideous.

 

Thinking of ways the alternator could fail whilst standing for two weeks, all I can come up with is that the carbon brushes have stuck in their holders, rather than being sprung onto the sliprings, so may not be making sufficient contact to energise the windings.  If you're feeling 'experimental' try giving the alternator body (towards back/non-pulley end) a few taps with a rubber or wooden mallet, to try to shock them free?

 

[Schm565]

Just tried tapping it with a rubber mallet, no difference on the multimeter. Think I’ll have to accept defeat and have it looked at ! Thanks for the suggestions though 👍

[mrgf]

On 14/08/2020 at 16:01, Schm565 said:

 

I’ll try swapping with the battery out of a little Agila , it’s recently been changed so I know that’s a good one., hopefully that won’t cause any issues

No luck with that battery, then?

[Schm565]

5 hours ago, mrgf said:

No luck with that battery, then?

No, just tried it, no change. So it’s definitely not the battery. Also tested the fuse which is ok. So I suppose either the alternator has somehow seized up as you suggested or there is a loose cable or connection somewhere between it and the battery(?) which occurred whilst the car was parked. Or i wonder if there is a sensor/switch which turns the alternator on which might have broken? 
So it’s  looking  like like I need to find a mobile mechanic...

[rum4mo]

Time will tell, it could just be an electronics failure in the alternator's regulator/control pack, they tend to "go" without any warning.  For example I started my daughter's late 2009 Ibiza up, reversed back up the driveway and as I stopped at a give way 300 meters later the charge (failure) warning came on, I turned round and took another car. Checking that car out proved the alternator was not charging so with like little chose of buying parts locally, I bought an exchange Bosch same rating one at a good price from ECP, and that sorted that out. The plan was for that daughter to keep that car for a while, so I just wanted it sorted out as best I could,  that alternator when removed looked as good as new - but it was faulty, the ECP guy had never seen a "good looking" clean Bosch alternator fail before, always a first time.