New battery, light still on dash

[rayraymundo]

13 plate seat ibiza 1.2 petrol. Car died, battery light came on. Jump started fine, light went off and then wouldn't turn over later that day and light back on. Replaced the battery, car turned over fine but battery light still on and window switches are sluggish, radio and interior lighting still works, no dimming of the headlights but feels sluggish to drive too. Google and car forums point me to it being the alternator but could it maybe just be the fuse? None of the local garages have any space before new year to even look at it so trying my luck here to see if anyone can advise me any further. Changed a minor fuse (rear wiper) the day before this started happening, but it's an old car so could just be a coincidence. The car starts and drives (not using it, just had it up and down my street), but light just won't go away and electrics seem a bit off and now just noticed the dipped and high beam dash light not showing when lights are on and high beam is switching the headlights off. The battery light comes on about 10s after engine goes on. I don't have a multimeter and seen a lot about parasitic draw tests but they mean nothing to me. I'm willing to learn within DIY capabilities if anyone has suggestions? Thanks.

 

[RUM4MO]

One thing that you could do is, buy a cheapish digital volt meter, set it to read DC Volts and on range that safely includes 12V, then open the bonnet and measure the battery voltage with the ignition switched off, record it. Now, start the engine and switch the head lights on, then measure the battery voltage, record it..

Next, if you can get someone to sit in the car and press down on the accelerator pedal until the engine is running at a fast tick over 1500+RPM, then measure the battery voltage and record it.

Report back with your measured results.

Note, you can measure the battery voltage by pressing the red(+ve) lead's probe on/into the battery's +ve terminal, press the black -ve lead's probe into the alloy material of the engine as that is connected to the car's body ie earth return.

 

[rayraymundo]

One thing that you could do is, buy a cheapish digital volt meter, set it to read DC Volts and on range that safely includes 12V, then open the bonnet and measure the battery voltage with the ignition switched off, record it. Now, start the engine and switch the head lights on, then measure the battery voltage, record it..

Next, if you can get someone to sit in the car and press down on the accelerator pedal until the engine is running at a fast tick over 1500+RPM, then measure the battery voltage and record it.

Report back with your measured results.

Note, you can measure the battery voltage by pressing the red(+ve) lead's probe on/into the battery's +ve terminal, press the black -ve lead's probe into the alloy material of the engine as that is connected to the car's body ie earth return.

Thank you, just had a friend along with his multimeter and its reading at 1.12 I think he said. So it's definitely not doing what it should be. So it sounds like a new alternator is needed, he only measured it on idle but I know it should be around 14v is that right?

 

[RUM4MO]

Yes it should be around 14V at least at fast idle.

 

[RUM4MO]

Yes it should be around 14V at least at fast idle.

I suppose that I should add extra detail or conditions to that posting, ie as long as the battery is needing recharged and/or the car is requiring "quite a bit" of electrical power - as it will if the headlights have been switched on, then what I wrote stands.
The alternator will react/adjust to the electrical demands being placed on it, so if, and only if, the battery is now charged or recharged to its correct level, and the electrical demands from the car systems are extremely low, the alternator's output voltage will fall back towards 12.4V or near that.

In other words, what your friend found when he checked your car indicates that the alternator, or at least the charging system, is not working as needed, and with a working alternator, or at least a working charging system, at fast idle, with the headlights switched on, the expected alternator output voltage should be as your friend suggested.

I was looking after my older daughter's 2009 SEAT Ibiza 1.4 16V SC back in 2016, one day I started it, reversed back up my driveway, then drove off to work, within 50 meters, the charge warning light came on, so I turned round and drove back home and grabbed my car. That was the first time that I had ever had an alternator fail on me. After work I checked it over and it looked like the alternator was dead, ie not charging, I fitted a new alternator and that sorted out problem completely.