Dimly lit battery warning, flickering headlights

Khranok · Mar 13, 2013

My battery warning light stays on when I turn the ignition. Giving it a few revs makes it turn to a dimly lit state. The headlights won't come on properly either, they just flicker. They are a HID kit though and have always required a few revs to get them to come on to full brightness once turning them on. The alternator seems to all be wired up properly and there are no other electrical problems so I can see, spot lamps work fine, central locking etc. Checked all the fuses too.

Any suggestions? Dieing alternator?

DEFENDER90-DAZ · Mar 13, 2013

Check the voltage you are getting at the battery using a multimeter set to volts you should be getting 13v+ at idle

But if the warning light is on/dim with the engine running it looks like your alternator is on its way out !

Khranok · Mar 13, 2013

DEFENDER90-DAZ said:
Check the voltage you are getting at the battery using a multimeter set to volts you should be getting 13v+ at idle
But if the warning light is on/dim with the engine running it looks like your alternator is on its way out !

I think the battery has been having a slight drain for a while too. Could that also be the alternator perhaps?

storm99 · Mar 13, 2013

Yes, your battery isnt being re-charged after starting. Once the alternator kicks in your battery isn't used. It will not last long if you're using battery power for lights etc.

Khranok · Mar 13, 2013

storm99 said:
Yes, your battery isnt being re-charged after starting. Once the alternator kicks in your battery isn't used. It will not last long if you're using battery power for lights etc.

It does give it some charge, maybe not enough though. On fairly long journeys my headlights have always stayed on, although lately they have been struggling to come on a little more than normal but once they are on they do stay on. I understand them ballasts need a significant charge to come on however.

Khranok · Mar 13, 2013

Read that a shorted diode in the alternator can cause a parasitic drain when the engine is off?

storm99 · Mar 13, 2013

Khranok said:
Read that a shorted diode in the alternator can cause a parasitic drain when the engine is off?

Hmm...interesting theory, sounds theoretically plausible dependant on the perceived collatoral impact viability.

Could be bollox though.

Khranok · Mar 13, 2013

Haha, guess I will have to borrow a multimeter from the parents and check it tomorrow or Friday

The Mad Hat Man · Mar 13, 2013

take it to halfrauds. they will test it foc

Khranok · Mar 14, 2013

The Mad Hat Man said:
take it to halfrauds. they will test it foc

Take the car or take the alternator out and bring it to them?

storm99 · Mar 14, 2013

Car with alternator in situ.

Khranok · Mar 14, 2013

Right booked it into Halfords for a battery and alternator test on Saturday. Think I may buy the 100amp alternator while i'm at it if this one is shot. The engine always dips a little when I put my spot lamps on as well as the HID headlights, plus I wanna put a subwoofer and amp in the back soon too

Khranok · Mar 14, 2013

Also I have a 200tdi disco engine in mine, do I take the old alternator out and remove the front pulley

and remove and replace this one with the old one

As they obviously use different types of belts?

the_wolf · Mar 14, 2013

Didn't the disco 200tdi's have 100 amp alternators anyway?

Khranok · Mar 14, 2013

the_wolf said:
Didn't the disco 200tdi's have 100 amp alternators anyway?

I think they are 65 amp, dunno if my old alternator was used or the disco one.

storm99 · Mar 14, 2013

Khranok said:
I think they are 65 amp, dunno if my old alternator was used or the disco one.

Correct.

Khranok · Mar 16, 2013

Yeah as thought it was the alternator not giving a charge. So if I order the 100amp one its just a case of taking off the old one, taking off the 200tdi style pulling spool and replacing the newer 'serpentine' style one on the 100amp alternator with that?

Then just slap the new one on and good to go right?

DEFENDER90-DAZ · Mar 16, 2013

I'd use heavier cable from the alternator to the common live on the starter motor to cope with the possible 100amp output of the alternator

Khranok · Mar 19, 2013

Fitting my alternator tomorrow, the wiring I currently have looks similar to this...

With the two thicker brown ones connected to the same point. It also has a green wire attached to there that goes somewhere down by the headlights, I dunno what that is, I will just slap it back on where I found it.

Will I need to upgrade these two wires to a higher gauge before fitting the 100amp alternator? These ones were connected to the 65amp prior. If so where can I find them (Halfords?) and what gauge should I get?

Thanks

Station House · Mar 20, 2013

Would deffo upgrade the brown wires back to the starter - might just be the piccy, but looks like one of your brown wires might have an insulation crack anyway (one with the yellow ring connector), so well worth swapping out

Halfrauds should sell or any decent motor factors - there are charts for the cble gauge, but they are usually current rated anyway - just look for 100 amps +

EDIT: Had a quick google for you - 2 gauge should do but personally I'd over spec and go 1/0

Dimly lit battery warning, flickering headlights

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