Hi guys and girls I just brought a vl berlina for $250 lol and funny enuff it is a great car but I am having a problem finding out why my battery keeps dying now the charge off the battery when connected and car running is around 13.50 with lights on its around 12.90 pretty good for an old alt . Ok so knowing that if the alt was stuffed the battery would last longer then 4 hours having to disconnect the battery every time I park up So I'm thinking I have a open circuit like a light still on eating the power I have checked the boot light , glove box both turn off when closed so I'm open to any other ideas ????? Being a $250 I had to hot wire the car now done up to a push button switch And if your thinking ohhh that's it, the previous owner had the same problem but the ignition worked with a alarm so it's def not that Let me know guys n girls Thanks all have a good weekend Ps I'm on the jacks haven't spell checked lol don't give me crap Some original photos have not been recovered yet.

So the battery only lasts 4 hours? Try changing over the alternator, as it is the most likely reason, but if it doesnt fix it, at least you can rule that off the list, Second thing it could be, is your battery itself could be old and stuffed, if your battery has gone completely flat on multiple occasions, its life expectantcy has been dramatically reduced

Looks like ill be changing the alternator then , the battery was brand new lol yeh 4 or 5 hours then dead, does a alt draw power when a car is turned off ?

Do the terminals spark alot when you connect them to the battery? Like more than any other cars you may have had? If so it would suggest a short circuit, otherwise if you have a multimeter have a look at the amps being drawn when the ignition is off and try to isolate where the power is going

Probably start with replacing the alternator and load test the battery. If your still having issues after that, put an amp meter on it as Gab said and check If there is any parasitic draw. If there is, start pulling fuses until you find the circuit that is causing the issue.

With the ignition off it should be reading 0 ohm?

switch the multimeter to amp resistance is not going to show you current draw

The only way to check whether there is a parasitic drain on the battery is to get a clamp meter and take the current reading while the ignition switch is off, then start pulling out fuses 1 by 1 until you isolate which circuit is causing the problem. There are accessories in the car which do drain the power such as the clock in the automatic models while the ignition switch is turned off. If the battery is not a sealed unit, check the cell levels, top up and charge the battery if necessary, check the cell gravity with a hydrometer , check to see if it reads a minimum of 1.200, I know 2 of the cells in mine read 1.150 but that doesn't cause me any problems, a couple of nights of below zero temperature actually froze the battery acid I think and I nearly couldn't start the car. Check all the earths for cleanliness & tightness, if the battery terminals are old or still have the factory terminals on them, replace them (factory terminals are crap), clean the battery posts and fit & tighten the terminals. Fully charge the battery or take it for a bit of a drive, turn the ignition off and turn the high beams on for 10 minutes, after that, try to start the car, if the battery gravity was o.k. but the starter won't crank the engine over, then the plates are stuffed - replace the battery, you should still be able to start the car after 10 minutes. I know in my car I intermittantly have a slow cranking problem in my VY , I'm putting that down to either worn alternator &/or starter motor brushes, I'm looking to replace the alternator & wiring as I'm looking to upgrade the charging system by fitting a 230 amp Silverado alternator into it, they use them on the older Chev engines but they are a straight bolt up fit to the LS1 engine, the only thing I have to change on it is the plug.

I had this problem, alternator was fine, battery was fine, traced to a relay that was open, wasnt a faulty relay, I had to pull it every time I parked it up, sent it to auto elec, ended up being the computer, not sure if water damaged or not but changed that over and fixed the problem.

Hi people Thanks for the help in the end the alternator was working but it was also taking 5 to 6 amps of power back just placed a spanner on the pulley bolt and it was magnetized simple but bloody annoying all fixed now thanks again