Probably electrical fault-turn lights on and batt dies! HELP

[TWSTD]

So last night I was driving around, my headlights on automatic as they always are, raining heavily, headlights on. I reach my destination, turn the car off, arm it and walk into the store. Upon my return 10 mins later i try to start the car and the alarm siren makes a few dying sounds as the batt completely drains of power and the batt backup siren chimes in (albeit rather sickly sounding too). Strange me thinks - how could my batt have gone flat? Lights were not left on or anything. So turn the headlights from auto to off, and get my jumper pack out the boot. Car jump starts fine. As soon as i turn the lights on she dies again instantly!

Now this to me sounds like a short in the lighting circuit right? Any ideas where i would start looking or how this could have occurred all of a sudden? Car is a 2001 Altezza Gita.

AL

[Bling]

Is the battery fine?
Does it crank the engine over fast or slow?
Check the voltage across the battery terminals when car is off and when car is running. Voltage will read 14-16v usually when running.

Just to eliminate the battery / alternator from the mix

[B1NZ]

Has the battery terminal/s come loose, corrosion between terminal and connector?

[darkwolf]

Check voltages and current at the fuse when the lights are on versus off.

[gepsk8]

Voltage will read 14-16v usually when running.
16volts ur cooking ur battery if its charging over 14.8volts
dies instantly, if u battery was bone flat, it would dies as alt working to hard to keen motor running, the battery charge and lights would just overload system.
charge battery, get battery checked, check charging system and current draw.

[darkwolf]

Voltage will read 14-16v usually when running.
16volts ur cooking ur battery if its charging over 14.8volts
dies instantly, if u battery was bone flat, it would dies as alt working to hard to keen motor running, the battery charge and lights would just overload system.
charge battery, get battery checked, check charging system and current draw.

That seems very strange. I've ran my battery flat countless times, always been a case of straight jump start, away I go, lights, subs, lock stock. Sounds more like a short of some kind. Though why it won't pop a fuse instead of turning off I'm not sure. Unless the fuse is too high.

[gepsk8]

if u battery was bone flat, on it way out as im guessing, u over load the system,
start with basic which is battery!

[matt dunn]

Wont be the battery.

A car will run on the alternator with no battery at all if it has to.
Not recommended but will work.

From factory the alternator will supply enough current to run all the electric's in the car turned on at once and still have current to charge the battery.

If you turn on the headlights and the engine stops,

either the battery is flat AND the alternator is not charging,
and there is not enough current left in the flat batt to run lights and ECU,


or have seen on a caldina where it was a stuffed ECU, and you turn on an electrical load and the car stopped.
Have only ever seen this once and highly unlikely but can be.

Make sure the alternator light comes on when you turn the key on before you start the engine, and go out when the engine does start.
(may need to jump start if it's flat)

[sergei]

Also I would like to add that if normal service free, heavy duty battery goes flat, even if you recharge it, it will not regain initial capacity. After a few those discharges it might not hold the charge at all.
Voltmeter will not show battery capacity. Closest thing is one of those load testers.

[TWSTD]

OK - so i charged the battery for approx 40 hours at which point it finally registered as fully charged. Back in the car and all seems to work fine - however I suspect the battery may be on its way out. I was just thrown by the way it killed the engine when the lights were turned on - it seemed very off behaviour to me - but i guess a dodgy battery can exhibit in many ways...

[Bling]

40 hours, what an effort!!

Might pay to pop into a battery shop and ask them to check it so that 2 weeks away you don't have same problems.

[gepsk8]

40hours, lol
hope u have good battery charger with voltage sense, and trickle charge.