Battery Light On. Why?

[Asad.C]

Hi Guys,

Just upgraded the turbo on my car and intercooler etc. Started the car a few times on different days and same problem each time.

The battery light comes on after 10 mins of it running. My friend who is a mechsnic Ccecked the alternator with a multimeter and said the battery is charging correctly and the alternator was giving out 13.9v and was working correctly. He said he could not see anything wrong with the alternator.

Anyone know why the battery light keeps coming on after 10 mins and stays on.

Thanks

[Nuts]

Dumb question: Did Measure it when the light is on?



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[Asad.C]

Yes. Same results.

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[pointz]

Is it not meant to charge at 14.5v ~

I would check the amps not just voltage and check the grounds are clean and making good contact.

[Dastardly]

13.9 volt is still enough to take the light off, plus he may of had something running like blowers or something.

[Dastardly]

Does the battery light come on when you first turn the ignition on and go off when you start it as normal?

[Asad.C]

Does the battery light come on when you first turn the ignition on and go off when you start it as normal?

Yes it does.

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[Dastardly]

What is your idle rpm when it's warmed up? If it's too low that could cause the battery light to come on and the alternator to not charge properly.

When the light comes on is the engine idling or are you driving it down the road?

[skyshack]

How many miles has it done?

Alternator brushes last a long time but not forever. I've got 2 in the shed that need new brushes. Page EL-27, I'm trying to work out a way to safely heat the end bearing box without buying a 200W soldering iron. Service manual says "Do not use a heat gun, as it can damage the the diode assembly".

[Asad.C]

What is your idle rpm when it's warmed up? If it's too low that could cause the battery light to come on and the alternator to not charge properly.

When the light comes on is the engine idling or are you driving it down the road?

idling at the moment at 900 ish. Only checked whilst idling, need to get it insured, taxed, MOT etc before i can drive it and check it out.

[Asad.C]

85000 miles.

Thanks.

[Asad.C]

Hi Guys. So I took the car round the block for a sneaky spin.

Battery light is no longer coming on. I had the car on stationary for 30 mins and it didn't come on. So looks like problem is sorted.

I did a few tests using a multimeter today whilst I was working on the car over a period of 4 hours. I'm not sure of what figures I should be looking for but the figures I am getting are not consistent.

Ran car for 30 mins. No battery Light.

Test 1. Ran for 10 mins
Car Running: 13.50 - 13.58
Full Beams on : 13.56
Heater on No.1 and Full Beams on: 13.53
Heater on No.4 and Full Beams on: 13.29 - 13.37
Battery after turning car off: 12.88

Test 2: 20 mins after test 1. Ran for 20 mins.
Car Running: 13.90
Full Beams on : 13.76
Heater on No.1 and Full Beams on: 13.70
Heater on No.4 and Full Beams on: 13.55 - 13.60
Battery after turning car off: 12.99

Test 3: 2 hrs after test 2. Ran for 10 mins.
Battery with car off: 12.75
Car Running: 14.19
Full Beams on : 14.05
Heater on No.1 and Full Beams on: 14.0
Heater on No.4 and Full Beams on: 13.5 - 13.8

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[auz200sx]

Good car it told you what it needed.

[Asad.C]

This thread can be deleted. Thanks