Using ISTA+D: Power Supply Not Adequate

[dregan]

I was planning on a quick look at the car's data using ISTA+ D. Initially, I didn't connect car to a power supply, because I thought a few minutes wouldn't kill the battery/system.
Steps I took:
1. I installed EDIABAS, ISTA+ on my laptop; both seemed fine.
2. I connected to the car K DCAN USB cable, turned on ignition on with engine off.
3. ISTA+D connection was good, pulled data from the car.
4. Battery warning light came on after ten minutes. I disconnected ISTA+D, turned off car and plugged into a trickle charger and charged battery over night.
5. Next day after battery was fully charged, I disconnected the trickle-charger, connected to the car with ISTA, hit start button from outside the car. (My computer setup was outside the car).
6. ISTA didn't want to connect, so I checked the OBD connection and noticed that the instrument panel in the car was dark even though it came on when I hit the start button before.
7. I disconnected from car, connected the trickle charger (my monumental FU) and re-connected to the car with ISTA+D, hit the ignition button then read the car. I immediately noticed that the basic information about the car was wrong (examples: had more than twice the mileage, had AWD listed when it's actually RWD etc). When the the reading of the control tree finished, almost of the modules had errors. I shut down everything except the trickle-charger.
8. An hour later, I tired to start the car - nothing - dead.
8. At this point, I stopped everything, I left the car back the trickle-charger thinking I'd charge the battery, then take it to my BWM mechanic to handle the ride-height adjustment I was planning on doing.
9. I checked on the car a couple of hours later and it was clicking, the lights were flashing and I panicked. I quickly disconnected the charger, then the car battery which stopped the clicking etc.
10. I checked the charge on the battery ... around 12 volts.
11. Reconnected the battery to the car - same as before - the car was clicking, lights coming on and off etc. Disconnected the battery.
I don't know enough to troubleshoot this problem, but it seems like I fried the ECU. Not sure what to do, but I am afraid to touch the car given that I'm a confirmed idiot.
If anyone has any ideas I would be extremely grateful given that I just got this car three weeks ago.

[flyfishvt]

I really doubt you fried anything. You're ignoring the obvious. Your battery is dying or dead. Remove the battery and take it to any parts store to have it load tested. Voltage reading on your test meter is useless. I can string a bunch of D batteries together and get 12 volts. It won't start the car though. The load test will test the Amp output.