Hey guys,
Well this started 3 days ago, everytime i start my car when it's cold the battery light will come no and stay on for a few mins (til the car is warmed up) and then go off. I know the battery light comes on when there is a problem with the alternator but this alternator is fairly new and so is the battery.
How does the battery light signal that the charging system is offline?
I know the voltage when car is cold is lower than when it is warm, does the battery light go off the voltage being too low?
Any help would be great :).

yes.

When your voltage is below a certain amount, isnt it like 8 volts? thats when the light comes on, thats how it diagnoses your charging system as being inadequate to hold the batteries charge.

yes.

When your voltage is below a certain amount, isnt it like 8 volts? thats when the light comes on, thats how it diagnoses your charging system as being inadequate to hold the batteries charge.
hmmm that's what i thought.
So when the car is cold the voltage is too low but then the voltage is upped when the car is warm. That's what i thought, now i just gotta work out WHY it's doing this.
Anyone know why it's not keeping voltage with a cold engine?

Thinking the most logical explanation is my battery is going flat, but it's still fairly new, how long are they suppose to last for?

this sounds like what happened with me yest on my way home from work, interesting stuff.

Thinking the most logical explanation is my battery is going flat, but it's still fairly new, how long are they suppose to last for?
Recommend a change every 3 years.

If you are with RACV, call one out and get them to test your battery for you.

Hmmm i think i'll take it into autobarn they have a free battery test in there. Also thinking of taking my car round to where i got the alternator and getting them to look at it (Auto elec).
The battery light is now staying on while the car is running and will not turn off, though the car does seem to still be running fine :doubt: .
I'd just like to get it sorted out before i run flat in the middle of nowhere :P.

Also i bought the alternator and battery nearly exactly a year ago.

I think its your alternator then, unable to charge your battery sufficiently during the course of your car running.

I have no ideas to add but..

when I was down at Mitsubishi getting the code for my stez I overheard a guy asking about the same prob :confused: and well they just brushed it off and said it'll be fine in summer :nuts:

Just got a battery test done but all they could tell me was that the battery was fine and that the charging system is faulty. I'm hoping it's just a worn regulator/brushes, will take the alternator back to where i got it :).
How easy is it to replace the brushes as this is a 3rd of the price for a new alternator?

Thanks for your help guys!

A relatively new alternator with worn brushes? You've been done dude :P

Brushes are simple to replace, just need some basic soldering skills. Although brushes shouldn't cost 1/3 of a new alternator, shouldn't be anymore then $30 for the set from Repco.

Ok guys it was the alternator but it wasn't worn brushes.
We took it back to the auto elec, he tested it, sure enough it was faulty, asked if we had 30 mins to spare, took old one out, whacked a new one in and now it's good as gold. The auto elec was surprised it didn't last as long as it should, still got another years warranty though so should be right :).
Dunno what was wrong with the alternator though.

Ive Got A Excel 98 Thats Beed Back To The Auto Elec 4 Times Because The Reg Keeps Failing There Must Of Been A Bad Batch Of Regulators It Keeps Over Charging At 18volts Then It Wont Charge At All Normaly Altinators Charge At 13.5 To 14.3 Volts Mine Was Hitting 18 Volts And Then Droping Down To 12volts When It Was Over Charging The Head Lights Were Brighter Than Normal And The Rpm Was Higher So It Must Of Been Confusing The Hell Out Of The Ecu It Also Used A **** Load Of Fuel.......anyways Im Hoping The 4th Reg Is A Good One Or Ill Take It Back Again And They Can Have A Nother Go At It ....goto Love Waranty