Battery drains

paul lambers · 9th January 2020, 13:27

My battery drains within a couple of days. The battery is brand new, and I fully loaded it. There are no lights on anywhere in the car after closing the car, satnav shuts down properly etc. Testing with a voltmeter shows normal charging of the battery. My garage searched for leakage of currents and also did a 12 hrs measurement and couldn´t locate any unwanted, unusual currents.

I searched the forum and found that a failing alternator diode can drain the battery after shutting down the engine. I checked this with a voltmeter and when the car is running, it shows about 27 volts when put on AC. So now I think it is a failing diode. I also notice that the lights of my dashboard are and stay very dim when I put on the head lights while driving.

My garage doesn´t believe the alternator is the cause, as they didn´t measure any unwanted current and the alternator charges the battery properly.
So, can the alternator be broken (diode) and the current it draws back not being detectable the way they measure, does anyone know?

Paul

9th January 2020, 13:27	#1
paul lambers Regular poster rover 75 2.5 saloon Join Date: Nov 2007 Location: Gelderland Posts: 55 Thanks: 0 Thanked 1 Time in 1 Post	Battery drains My battery drains within a couple of days. The battery is brand new, and I fully loaded it. There are no lights on anywhere in the car after closing the car, satnav shuts down properly etc. Testing with a voltmeter shows normal charging of the battery. My garage searched for leakage of currents and also did a 12 hrs measurement and couldn´t locate any unwanted, unusual currents. I searched the forum and found that a failing alternator diode can drain the battery after shutting down the engine. I checked this with a voltmeter and when the car is running, it shows about 27 volts when put on AC. So now I think it is a failing diode. I also notice that the lights of my dashboard are and stay very dim when I put on the head lights while driving. My garage doesn´t believe the alternator is the cause, as they didn´t measure any unwanted current and the alternator charges the battery properly. So, can the alternator be broken (diode) and the current it draws back not being detectable the way they measure, does anyone know? Paul Last edited by paul lambers; 9th January 2020 at 14:06..