Battery / Alternator Issue...

[Charles89]

Well the problem isn't just at idle sometimes... My car could be in gear and at about 2000rpm and it still happens...

I'm thinking a bad connection somewhere? Like a bad earth?

[89CAL]

Ah ok.

Yeah it could be. Check the connections to the alternator. There should be a 2 pin (from memory) connector thats for the activation of the altenator. Check all the earths etc as well. My Girlfriends mum has a similar problem with her mazda 3. Sometimes the battery light comes on and theres no charge from the alternator.

See what you can find. Just trace as many wires as you can. If you've got a multi meter to test stuff as well probably a good idea

[jrm]

It was already pointing at an alternator problem, changing the battery pretty much proves it.

Could be the wiring to the alternator, could be the alternator itself. Taking it to an auto-electrician will be the quickest way to tell.

[Charles89]

I've just done a test with a multi meter. Here's the results.

Car off 12.25v

Car on 13.9-14.1v

Revving the car 14.1v

All high and low beam with ac on full 13.8-13.9v

After 5mins 13.75v

Car off again 12.5v

From the readings above it seems like the alternator is doing what it's meant to be doing.

But for some reasons. I can't seem to do a battery drain test... I'm not getting any readings at all. Just a negative sign and I set it on 10A on the meter.

[Charles89]

I think I've just completed a battery drain test. It reads about 0.20, but once I took out the LED globe in boot, it reads about 0.17-0.18. Pic below, did I do it right? lol

Anyway, I cleaned up all my terminals and fixed up my earth kit (which one of the bolt was a little loose (could be the problem)) and cleaned up a couple of the earth points.

And now the car seem to run fine and starts fine again.

It is idling at about 900 and the voltage reading on the MFD is much much more straighter than before (was spiking up and down), and when I turn highbeam on while idling, the car still runs pretty smooth without wanting to stall.

So I think I might have fixed the problem. Will keep you updated

[Missileman]

I don't like like that reading 12.25v to me that indicates a flat battery. Any reading below 12.65v is an indication of less than full charge, I like to see mine between 12.80 and 13.10v after resting over night. and there in lies the problem with measuring state of charge by using a multi meter to test open circuit voltage, to get the best accuracy the battery needs to rest up to 24h after charging/ discharging for the cells to equalize.

Pull the battery and put it on a charger over night then take it to an Auto Electrician to test.

[Charles89]

Well my old battery reads 12.66....

[Missileman]

12.66 is just OK

I have two standard 330 CCA batteries, one is a little bit sus and one is 6 months old and is in great condition, both are the same brand and model, the sus one is in my car which hasn't been driven in two days and reads 12.84v the other came off the charger about two weeks ago and reads 12.95v

so the 12.66v reading is here nor there, what the sparky will do is connect it up to a heavy load for a couple of seconds and watch how the low the voltage drops and how it rebounds as the load is removed, this will give a good indication on the health of your battery.

Edited January 3, 2012 by Missileman

[89CAL]

A 6 cell battery at 2.1v per cell = 12.6v. with car off this is a good reading.

You need to get a carbon pile test done to tell you the health of your battery. mine had 12ish volts but was wrecked. only load testing would show this. Or checking voltage while cranking

OP have you checked the alternator wiring yet?

[Charles89]

Yeah I checked the alternator wiring and it seems all good.

But yeah, I think the car is performing pretty well at the moment, so far so good!

[Charles89]

After thinking the problems is fixed, it is back again....

What else can I check?...

I've got an earth kit in the car, which connects the battery's neg, engine earth, chassis together and I've checked each of those groundings and don't seem to be a problem.

As for the alternator, it seem to be putting put 13.8-14.3v so...

HELP! :S

[89CAL]

Ok so the alternator is charging fine but your battery is still going flat yes?

So after turning the car off it starts ok but if left overnight or so the battery is flat? sorry if I've misunderstood just making sure I know where your coming from

[Charles89]

Yes, the alternator seem to be charging fine. And no I don't think the battery is flat.. Most of the times it starts the car, but might take a couple of tries.

Because when I last checked the battery today, it was about 12.45v.

And the problems still occurred tonight; when I turn highbeam on, the voltage would drop from 14v to 12.5v and rev would drop to about 500, headunit will restart, MFD will restart but the car will eventually recover.

I'm really thinking I have bad grounding somewhere...

But I can't seem to find anymore earth points... there is one that I can't really get to and that's underneath the engine and it connects straight to the battery's neg.

[89CAL]

hmmm yeah sounds like a bit of a wiring problem. Does it only do it with high beams or any high electrical load?

If its only your high beams then there must be a problem with the wiring for the high beams, like you said the earth for the high beams may be dodgy. The 34's had Xenons that get removed during compliance yeah? Maybe they did something dodgy when that happened and its showing up now?

Just guesses but if it is ONLY your high beams causing the problem then Id work backwards from there

[Charles89]

Well.. nah, it's not only highbeam, it's foglights too (they are factory but I've added them myself). As for xenons, I sourced a pair of headlights that's still got the factory ballast. But yes, my old headlights were converted to H1's.

So since it's any high electrical load that causes it, it has to be a connection somewhere...

But I do remember me dropping my AFM while taking the intakes pipes and stuff of to replace my blown gasket...

[89CAL]

it just seems a bit odd that its causing the revs to drop and your head unit to restart. So was anything changed/broken/swapped/touched before this started happening?

So high beams and foglights? Check for a shared earth I guess.

so when you say the car recovers, does that mean the revs drop etc then slowly the revs pick back up and voltage returns to normal (14ish volts)?

Ill have to have a think about that one

[Charles89]

Hmmm... It all started when my battery went flat after leaving music on for a few hours. We jump started the car (something coulda possibly happened there).

And yeah, the car would be idling at 800-900, then if I turn either of those lights on, my revs would drop to 500 for a few seconds, voltage drops to 12 or something, headunit restarts, MFD restarts, airbag light would come on (like normally when you start the car), then a few seconds later, everything will return to normal.

Revs would go back to 800-900, voltage will go back to 14 or so.

Also, another symptom of this is, when I'm idling at the lights with my indicators on, the whole dash light will dim with the indicators, which means even the indicators are causing problems, but I guess the load isn't as much as highbeam, so headunit and MFD stays on :S

[t_revz]

have you checked all the positive connections also? maybe see what the difference in voltage is when loaded up between the battery and the fuse panel

[89CAL]

you can check your earths if you have a multimeter by putting the negative on the chassis (at a good earth point or on the battery negative would work) and then probing the earth wires at your headlight circuits checking for resistance. If you get a high resistance on your earth circuits then that might be your problem. Basically if you know a thing or two about using a multimeter I would just go around checking as much as you can.

If you want some help doing this I can tell you what to check for, but really it sounds like your drawing a hell of alot of current which might not be so easy to check for, unless you know someone with one of these: Linky

Measuring the current draw will help alot when putting the high beams on

[Charles89]

I went through the engine bay again today, I found another 2 earths, one on left fender, one on right fender. I cleaned them both, sanded it back and the car seems to be back to normal again... So I don't know lol

What are those 2 earths for? I think the driver's side might be for headlights and something else.

Guess I'll just have to see how it goes again.