Battery discharging too fast

[Harker]

So if I leave my key on with the engine off to listen to the radio, they car won't start after about six minutes and will need a jump. Leave the headlights on and it will die after about 60 seconds.

I've tested the battery and the alternator and they are fine, putting on normal voltage.

Anyone have any idea where the problem is?

 

[1275]

so what voltage does it read after draining it?

 

[Harker]

so what voltage does it read after draining it?

I've never checked it after draining it, it's always died while I've been out.

 

[1275]

It sounds like the battery is shot, assuming you've been fully charging it after flattening it. If the radio goes off I imagine the battery will then show about 6 or 7 volts. But check it.

 

[pollyp]

assuming the alternators charging it at 14v, if you fully disconnect the battery after a long run (so begin with a fully charged battery and unplug it from any potential amp drain), leave it overnight, it should retain the same 12.4 - 12.6v for afew days.

if it goes below 12.4 or even drops out completely, the batterys dead & unable to hold charge. new battery.
if it holds charge fine but runs flat when connected to the car, there's a high amp load draining it.

check ur boot latch & light is proper shut off (easy to forget bout), all interior & exterior lights off.

 

[Harker]

It sounds like the battery is shot, assuming you've been fully charging it after flattening it. If the radio goes off I imagine the battery will then show about 6 or 7 volts. But check it.

The radio doesn't go off, it stays on but the car won't start, would need a jump. I checked battery with alternator when on and off and it was reading normal levels.

 

[infinity]

If the alternator is good and outputting 14v sounds like new battery time

 

[cdwood2010]

Yup, new battery time.

Batteries do strange things when they start to fail, I have had a couple recently that charged fine, tested fine on the bench, stood on the bench charged for days and the minute you open the bonnet they start to discharge. Fit them to a car, apply any sort of load, and they were suddenly at 6v.

Borrow a battery if you can to confirm, but that's likely your solution.

I've seen car batteries drain quicker with aftermarket stuff fitted (alarms, ice etc) but you really would need to be powering up a lot for it to drain that quickly.

Chris.