I'm trying to work out if my car has a fault that's draining the battery excessively, or perhaps that the battery itself is knackered (car is a 2010 TDCi Titanium).
If I leave a SatNav plugged into the interior 12V socket to charge (unit turned off), should this cause the battery to go flat within a couple of days ?
The battery has gone flat a few times lately while parked, preventing the car from starting the next morning. There are no lights left on, it's double locked and alarmed etc..the only thing I can think of that's using power is the SatNav.
It was flat again this morning. I'd driven about 50 miles on Sunday, and my wife about 10 miles yesterday. The SatNav had been plugged in since Sunday.
I actually took the car to Halfords on Sunday after the 50 mile drive, for a battery diagnostic test, and they found nothing wrong with the battery and charging voltages. The only thing he noticed was that the overall battery voltage was low, which suggested it wasn't getting fully charged. He suggested our problem could be because we only do short journeys with the lights on etc.. but I replied saying that could represent almost all drivers ! Besides, 60 miles in 2 days isn't exactly short journeys, and my battery was dead this morning.
While the battery was flat, I checked it with a voltmeter. It read 8.5V with the car unlocked, door open. It read 9.0V with the doors locked and car alarmed. With the wiring disconnected from the battery it read 10.5V
So it's still on charge now - something I'm getting used to.
Anyone else had any similar experiences ?
Also - just curious to know - I always disconnect the wiring from the battery before charging it. Is this necessary ?