Battery warning light

[neil_1821]

Apologies if this has been answered before but I'm on my mobile at work and I have an exam today so haven't currently got the time to be searching!

My battery warning light came on as I was driving to work, turned the engine off when I got here and started it again and it comes back on.

I haven't yet had chance to check the belt, however I doubt this is the problem as the temp of the engine remained constant for the rest of my journey and all belts were replaced a few thousand miles ago.

I will check cable/plugs and earth straps on my dinner, but failing that will I have to goto seat? I'd be stranded in Birmingham otherwise and I've got a 40 mile trip back home, assuming the battery isn't dead by the time I leave work

 

[neil_1821]

Yeah I should be able to lay my hands on a voltmeter, we have an electrical section. In going to be struggling to get home if my alternator is dead!

 

[domin8or]

Same symptoms i had a while back,mine was Alternator,but do checks to confirm.

 

[neil_1821]

I've checked the battery voltage, on idle it's 11.73v, doesn't increase when you increase the revs so likely symptom is alternator gone up the creek!

That's probably why my headlights used to glow a bit

 

[domin8or]

That's low on idle,should be about 13.5 I think.
Does sound like regulator on Alternator goosed.
If you have access to an Auto Electrician,i believe regulator can be changed on it's own,i unfortunately didn't have access,so it was an alternator for me.
I got mine from TMS motor factors,was best price at time.

 

[BoostHard]

I've checked the battery voltage, on idle it's 11.73v, doesn't increase when you increase the revs so likely symptom is alternator gone up the creek!

That's probably why my headlights used to glow a bit

Voltage shouldn't increase with revs by much
The alternator should produce about 14v no matter how high the revs are

Check the Voltage at the alternator instead of the battery,

The wire that goes from the Alt to the battery is known for building up resistance,
Check the auxiliary fuse box on top of the battery as well,

They can often get hot and melt as a result of the bad cable.

The alternator fuse/wire is the 1st one on the left of the box,





Edit: My car produces 14.3 at idle or at high RPM

 

[neil_1821]

I've had a good check of all cables and nothing seems wrong.

Going to attempt to drive the 36 miles home with no heater on, radio or lights, being a diesel it should make it since it hasn't got to power any coil packs.

Got a friend whose a mechanic and he said he'll check tonight for me!

Cheers for the replies

 

[BoostHard]

I've had a good check of all cables and nothing seems wrong.

Going to attempt to drive the 36 miles home with no heater on, radio or lights, being a diesel it should make it since it hasn't got to power any coil packs.

Got a friend whose a mechanic and he said he'll check tonight for me!

Cheers for the replies

How have you checked the cable?


Check the power from the alternator 1st,
Then again at the battery to rule out a problem with the cable..

I'm sure your issue will be with the alternator,
The golf I see this on was putting out 14.2 at the Alt, but only 13. something at the battery, The cable was getting very hot aswell.

Wasn't low enough to bring on the battery light.