Finally I had time and opportunity to perform some tests on the car. I will try to describe in as much detail as possible, what I do, since I think that will give you the most information to give me feedback.
This is the multimeter, I borrowed:
I attached the charger about 4 hours ago, and the battery was not flat, as I was able to open unlock the car doors with the remote when I got there. I did not measure the battery at that time.
Four hours later, I went to the car, started it up and measured with the voltmeter. It said 12.3v.
Then I put the red clamps around the thick black cable going to the negative pole (I am unsure if that is the correct term in English - but the minus thingy on the battery) and set the multimeter for amps. I recorded the screen of the multimeter, went into the car and used the throttle for a few seconds. The video can be seen here:
There is no sound, but it clearly increases in amps when I use the throttle and drop back down when I take my foot off.
Am I correct in understanding, that this actually means the alternator generates power and feeds it all the way to the battery? Or am I missing something?
I then proceeded to measure the voltage again and it said 12.1V. I then set the lights to parking, closed the doors and left the car idling.
30 minutes later, I went back to the car and measured the volts again. It was down to 11.0V.
I then kept the voltmeter on, put the camera on it and revved the engine. The volts increased a bit and then fell again when I took my foot off. Video: http://youtu.be/RoqR1uztuWU
Then I set it to amp-mode again, hooked it up to the negative side of the battery and did another video. http://youtu.be/0ZCmoYXdfRI Clear movement depending on throttle, not sure what to make of the numbers.
I then did a final reading of the battery, it was down to 10.4V. I turned off the car, removed the charger and came in to write this.
So to summarize the volt readings:
I am pretty confused. This is not my domain at all, but doing software development, I know how to think in logical troubleshooting and here is what it seems to me:
When the car is idling, the alternator produces less power than the car consumes (ie. the voltage drops). If the car is running at higher RPMs, it does seem to charge the battery (the amps change and the voltage increases, at least temporarily).
What do you make of all this?