VQ Battery Going Flat

[VQ Stato]

Hoping someone has some adivce for me. My VQ's battery is going flat. It is a relatively new battery, tests like a new battery.
I can charge the battery overnight, start and drive it in the morning, and that night when trying to get home from work, it is flat. It is happening intermittently and when l have had it tested, with the engine off, and the car locked it is draining bugger all amperage.
A mate has suggested it could be a sticking diode in the Alternator?

[beckrey]

take it to an auto electrician
and get your alternator tested
could also be a faulty battery

[mwethereld]

sounds like the alternator,,, its intermittedly ****ed, cause when it works the batt does,,,, i really dont think its the bat...

[Tasmaniak]

I'm going to assume you have acess to a multimeter.....
With the engine off, your battery should read about 12.6 Volts....when the car starts, it shoulr read then about 14.4 Volts with only the motor running, no stereo no heater and all the new fangdangled stuff. If it doesn't then the alternator is the issue. Most likely the brushes need replacing. It's a relatively easy job but I would suggest getting it done by an autoelec. It should be less then $100. Don't quote me on that though

If it's the brushes...whats happening is as you drive short distances, the battery ISN'T being recharged by the alternator. But, over longer drives, there is a little charge getting in.

When you say "bugger all amperage" How much exactly? .01A is acceptable, .05 is pushing the limit...anything else and you have something switched on.

If the multimeter is showing well over 14.4Volts, THEN you have a fualty diode in the alternator. BTW a diode can't stick. It's a non-mechanical part and doesn't move, it either works or it doesn't. and no, for all you smart arses out there, they are not teflon coated to make them stick free

[VQ Stato]

It is drawing 0.04A when switched off, and locked up. It looks like the battery is discharging when turned off eg. charged at night, by the next morning, dead flat - which wouldn't do this with 0.04A when drawn l would guess.
My mate suggested a sticking diode supposedly because if faulty they can actually draw current at rest, and intermittently? It obviously wasn't doing it when we read 0.04A though.
Can an auto elec do a test on the alternator and diode pack while the alternator is still in the car?

Appreciate the advise and assistance fellas.

[Tasmaniak]

A diode cannot drawer power....

A quick explanation in what a diode does....

A diode is like a one way sign it will allow electricity to flow one way but not the other. If used in a configuration of four it is able to turn AC electricity into DC. It doesn't stick. It cannot stick. It won't stick and it sure as hell doesn't draw current.

Everything you have said screams alternator brushes at me. This would be the first thing I would check if your car came into my workshop.

[FXST01]

I would check your interior, glove box and boot light, see if they are turning off when they should.

[VQ Stato]

I am officially a d##khead!

The car was drawing 0.04A, but on retesting, was drawing 1.28A. The auto-elec opened the boot and disconnected the boot light. The multimeter went back to showing 0.02A - what do you know!

I was only driving on small trips, and with the car sitting there all day and night, this was enough to drop the charge in the battery over a couple of days.

Thanks everyone for their advice, most appreciated.

[Tasmaniak]

Just as a sidenote, even if the car is fine continous short trips can still drain a battery.

My father has an old Camira that he uses to drive to work fro and back. It's a 5minute drive. If he doesn't take it for at least a 10-15 minute drive once a week the battery will flatten itself.

Stuck boot light....good to see it was something simple, did you get the switch replaced?

[RVN 355]

Good you found the problem, could of been alot more serious than you first thought.

[G4orce]

i had the same problem in my vp calais. i found that the boot light is on all the time so try taking that out. You also could have a faulty battery. good luck

[Tasmaniak]

I'm guessing you failed to read the ENTIRE thread eh Vp Calais? The problem has been fixed! lol