Draining new battery

[mark anthony thomas]

I've owned my 2005 3.0 s type since 2007 now with 83,000mls. But lately the battery is losing charge. I changed the battery as the one that was on there was 6yrs old. But with the new battery its draining within 3 days. I've checked the boot light, the glove box light, the interior light and the door lights. None of them are staying lite up. I tested the charging and its about 14.9v on tick over and 12.3v with engine off. It must be a big drain to kill a new battery in 72hrs. Anybody got any ideas or had similar issues. Thanks

[N6 JMX]

Hi Mark, that does sound very unusual to get a battery drain that fast. Have you checked the lights in the vanity mirrors behind the sun visors? If fitted, these lights on the vanity mirror stay lit all of the time if the sliding cover is not closed over, even when the sun visor is flipped back upwards. Obviously try and view your car in a dark space to see if there is any glow that can be spotted, but otherwise it would seem you can rule out courtesy lights.

Do you have any other accessories installed that could be taking power when normally they should power down with the ignition off? Something like a dashcam?

Finding a power drain is not a simple task unfortunately, especially when there is nothing obvious like something illuminated. Hidden drain on the battery could be the battery itself, try charging up the old / removed battery if you have it and connect it to the car via suitable jump leads, whilst having the newly installed battery disconnected. If the old battery also discharges rapidly, then your issue lies within the car and not the battery.

N6 JMX

[Jimbov8]

16 hours ago, mark anthony thomas said:

I've owned my 2005 3.0 s type since 2007 now with 83,000mls. But lately the battery is losing charge. I changed the battery as the one that was on there was 6yrs old. But with the new battery its draining within 3 days. I've checked the boot light, the glove box light, the interior light and the door lights. None of them are staying lite up. I tested the charging and its about 14.9v on tick over and 12.3v with engine off. It must be a big drain to kill a new battery in 72hrs. Anybody got any ideas or had similar issues. Thanks

The most likely cause of a drain that large is the “alarm chirp sounder”. The internal batteries degrade over time and short out causing the drain. Disconnect it and then see what happens.