Waggin

I've been connecting my 750mA battery tender to the car to make up with all the playing around I've been doing in the garage, but it won't top it off overnight, (it did on my 2006 A3)
I suspected the car's standby current draw was the same, or more than the tender could supply, so I used my bench power supply / charger.. Matched the battery voltage, connected it, then disconnected the car battery ground cable.. This way, the power supply was supporting the car, which was completely asleep by that time.
Result: Around 0.5A, which means the trickle charger was only pumping about 1/4 amp into the battery, explaining why it couldn't top it off overnight.
Just something else to know, for whatever it's worth. If you're going to buy a maintenance charger for this car, you want one that can supply at least a couple of amps.

Left display is current, right: voltage.

synergize

I have the same Fluke MultiMeter, topnotch tool!

Waggin

Yep.. Second one, replaced my 8024A. I also picked up the power supply cheap when some local electronic hobbyists store closed up (forgot the name) Came in handy when my cheapo battery charger died. I just set the voltage to 14, current limit in the 4-6 range and it works perfectly. (A bit heavy though.)

heisnuts

I think it must have a progressive shut down procedure because I left mine in the garage for 2 weeks when we were on a trip and it fired right up when we got back with no tender or charger hooked up for the 16 days it sat in the garage.