New battery and now the light is on :(

[titwonk]

Hi guys,
My 172 started loosing its charge after a couple of days, this problem got worse until the car would not even jump start! Dead battery I hear you say and the battery must of been well goosed. I bought a new battery and fitted it to the blue beast and she jumped straight into life, problem solved!

so I jump in the clio and take her for a spin and notice that the battery light and stop light was coming on when the revs were over 3500 rpm and would sometimes flicker below 3500 rpm. After 30 mins or so I pulled up and let the car just tick over for a bit only to find that the battery light is on at tick over now and will not go off at all! The light itself started off faded and is now fully illuminated!

Would we all say the old battery and my jump starting abuse has killed off my alternator? Just wanted to be sure really before I order a new one and take all the skin off my knuckles or is there a regulator or something I need to know about!

All this happened while I was taking my car to get a new sump fitted she's all good now with no oil leaks but a has got a bloody electrical fault instead! Damn clio, I can't wait till its perfect and I can get back out on track.

thanks all and I promise to document this problem here and I will hopefully post the solution for anyone else with these exact symptoms!

 

[Owen92]

You need to test it before anyone can tell you what's actually wrong. First of all check all the connections are secure and not covered in crap. Then use a multimeter to test the voltage from the battery. First with ignition off, then engine on idle - no load, fast idle (2500rpm) with no loads and finally fast idle with all loads turned on (lights, fans and radio etc)

 

[titwonk]

Ok thanks, I don't have a multimeter so I will go to maplins tomorrow and get one! I will report back with my findings although I do suspect the alternator to be at fault here!
The light is now on permanently due to the battery now having not enough charge having drove it for 30 mins? Does an engine need more electric the higher the revs?
What readings am I looking for on the multimeter?
Thanks again

 

[Adam G]

Try your local motor world/ATS etc. most offer free battery checks.

 

[Owen92]

Ok thanks, I don't have a multimeter so I will go to maplins tomorrow and get one! I will report back with my findings although I do suspect the alternator to be at fault here!
The light is now on permanently due to the battery now having not enough charge having drove it for 30 mins? Does an engine need more electric the higher the revs?
What readings am I looking for on the multimeter?
Thanks again

If the battery had enough charge to start with and after a drive (half hour should be ok) the battery is low again it sounds like you are looking at the alternator being at fault.
The readings you are looking for are around 12v for the engine off and then the other readings should be between 13.7 and 14.5v.
Where are you located anyway?

 

[titwonk]

Thanks for your help guys I'm in Kidderminster (worcstershire) I'm not sure I could get to and from the motor factors on battery power alone so think I need to get a multimeter! It doesn't help that my car resides at my moms so can't just nip out and check stuff
on the plus side I've got the car to a good standard other than this

 

[titwonk]

Sorry Owen can I just ask what reading would indicate a faulty alternator? Less than 13.7 at idle?
thanks again

 

[Owen92]

If the alternator isn't working correctly, the reading won't be higher or only very slightly above than the battery voltage at the start.

 

[titwonk]

Ok thanks, I will report back tomorrow

 

[titwonk]

Hi guys, just a quick update. Managed to get myself a multimeter and have some results for you to help with

the battery with out the engine on was putting out just under 12 volts, remember this battery was used on the car for 30 mins so I was expecting a slightly low reading.

the reading with the engine on was no different at all, still just under 12 volts and if I revved the car the voltage dropped further and when I revved it with the headlights on the voltage dropped as low as 5 volts.

After this i did use my battery charger on the battery for 10 mins and the battery soon picked up again from 5 volts to 12 volts so I think the battery is working as it should!

so do I go ahead and order a replacement alternator or could there be another fault?

Nothing has been touched on the wiring side at all and the car hasn't moved very far!

I do remember seeing the stop light flicker on when the old battery was installed and although I didn't notice the battery light at the time I'm beginning to wonder weather it started to show earlier than I first thought!

Anyway thanks for all your help

And I think the 172 cup has a different alternator to a full fat and a 182? Mine only needs to put out 75amps is this correct? I have found a 172 cup alternator but they did seem thin on the ground when trying to track one down.

 

[Owen92]

Sounds like the alternator definitely isn't working. Another idea would to just get a company like Halfords, Kwik Fit etc. to carry out one of their free battery checks aswell. That way you've got a new alternator and an answer on the battery itself.

 

[titwonk]

Ok thanks for all your help owen92 top stuff I will report back here once I've fitted a new alternator just to end the thread!

 

[titwonk]

Hi all, just going to end this thread because I fitted a new alternator and all is well again! Was a night mare getting the old one out the engine bay, had to unclip the fuel hose off the rail and even then it's a mega squeeze! Apparently my battery light was only coming on when being revved because it was the voltage regulator at fault. I'm glad I've got a cup as the alternator removal and refitting only took 40 mins
hope this thread may help someone else,
thanks again!